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Water vapour loss measurements on human skin.Valk, Petrus Gerardus Maria van der

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WATER VAPOUR LOSS MEASUREMENTS ON HUMAN S K I N

WATERDAMPVERL I E SMET I NGEN VAN DE HU I D

STELLI NGEN

Bij produkten bes temd voor h u i dapp l i kati e d i ent het effekt van deze

produkten op de hui dbarri ere bestudeerd te worden ( d i t proefschr ift ) .

I I

Het i rr i terend vermogen van rei n i g i ngsmi ddel en op de hu i d wordt voor

een bel angri j k gedeel te bepaal d door het effekt van deze mi dde l en op

de barri erefun kti e van de huid ( d i t proefschr i ft ) .

I I I

Het gebru i k van de predi katen baby zeep en med i ci nal e zeep d i ent

vermeden te worden , daar gesugg ereerd wordt dat respekti evel i j k

baby zeep mi l der i s en dat med i ci na l e zeep hui dafwi j k i ngen voorkomt

of geneest . Sei de i s i n a l gemene z i n n i e t j u i s t ( d i t proefschri ft ) .

I V

Het verwijderen v a n de vern i x caseosa b i j d e pasgeborene met water en

zeep d i ent vermeden te worden .

v De eendimens i ona l e i ndel i ng van i ndrogend tot hydrerend zoa l s veel a l

toegepas t b i j h e t beschri j ven v a n h e t veh i cu l um gaat voorb i j a a n de

compl exe i n teract ie tu ssen de bestanddel en van het veh i cu l um en de

hoorn l aa g .

V I

Acetosal ( asp i ri neR) kan een dodel i j k geneesmi ddel z i j n voor pat i enten

met urt i car i a ( ga l bu l ten ) .

V I I

Voor de behandel i ng van scab i es met gammexaan 1% kan met een

appl i kati eduur van 6 uur worden vol staan ( J . Am . Acad . Dermatol . 9 :

546-550, 1983 ) .

V I I I

Het gebrui k van komb i nati epreparaten i n de dermatol ogi e d i ent beperkt

te worden tot s l echts enkel e i nd i katies .

I X

Epidemio l ogi sche gegevens omtrent het v66rkomen van hu idz i ekten di enen

mede de i nhoud van het onderw i j s te bepal en .

X

' Genet i c counsel i ng ' d i en t een bel angr i j k onderdeel van de dermato l og i e

te worden ( Dermato l og i ca 167 : 197-203 , 1983 ) .

X I

B i j d e i nterpretat i e van de bepa l i ng van het speci fi ek I g E d i en t d e

gevoel i ghei d van het shoc korgaan betrokken te worden (Am . Rev . Respi r .

D i s . 120 : 1053- 1058 , 1979 ) .

X I I

Met behul p van reg i onal e transcutane oximetri e kan een betrouwbare

i ndruk worden verkregen omtrent de oxygena ti e van de hu id ter pl aatse

en de onderl i ggende weefsel s ( D i abetes 33: 527-531 , 1984 ) .

X I I I

Marathonl opers zi j n , mi ts goed voorbereid , geen dood l opers .

Stel l i ngen behorende b i j het proefschri ft

' Water vapour l oss measurements on human sk i n ' .

P i eter G . M . van der Va l k , Groni ngen 18 december 1984 .

R I J KSUN I VERS ITE IT TE GRON INGEN

WATER VAPOUR LOSS MEASUREMENTS ON HUMAN SK IN

WATERDAMPV ERL I ESMET INGEN VAN DE HU I D

PROEFSCHR IFT

ter verkri j g i ng van het doctoraat i n de Geneesku nde

aan de R i j ksu n i vers i te i t te Groni ngen

op gezag van de Rector Magn i f i cus dr . E. Bl eum i n k

i n het openbaar te verded igen op d i nsdag

18 december 1 984 des nam iddags te 4 uur

door

Petrus Gerardus Mar i a van der Val k

geboren te Haa r l em

Promotor : Prof . Dr . E . Bl eum i n k

Referent : Dr . J . P . Nater

{ Thes i s , State Un i vers i ty of Gron i ngen , the Netherl ands , 1984 )

Aan m i j n vader

Th i s study was carri ed out i n the Occu pat i onal Dermatol ogy U n i t ( Head : dr . J . P . Nater ) o f the Department o f Dermatol ogy (D i rector: prof . d r . A . H . Kl okke ) , Un i vers i ty Hos p ita l , State Uni vers i ty of Groni ngen , the Netherl and s . I t was made pos s i b l e by grants from the Jan Korne l i s de Cock S t i c ht i ng and the Research Fund , Department of Derma tol ogy .

Stati s t i ca l man i pu l at i ons were performed on the Cyber 1 70/760 computer of the State Un i vers i ty Groni ngen , the Netherl and s , u s i ng MSUED I T , WESP and SPSS program packages .

3

Determi nat i on of water va pour l oss throug h s k i n by the Servo Med

Evaporimeter .

4

Contents

I ntroducti on .

Chapter 1 : The barri er funct i on of the s k i n aga i nst d i ffus i onal 8 wa ter l os s .

Barr i er funct i on of the s k i n and i ts rel a t i on wi th 28 i rr i tant and a l lerg i c contact dermati ti s .

Water vapour loss as i nd i cator for barri er funct i on 36 impa i rmen t .

Personal and envi ronmental vari ables i nfluenc i ng s k i n 40

wa ter vapour l os s .

Methods o f measuri ng the evapora ti ve water l os s of 46

huma n s k i n .

Cha pter 2 : S k i n i rri tancy of surfactants a s assessed by water 68 vapour loss meas urements .

Chapter 3: The vu l nerabili ty of the sk i n to surfactants i n

d i fferent groups o f eczema pati ents and control s

as determi ned by water vapour l oss .

81

Chapter 4 : The i nfluence of repeated s k i n exposure to surface 9 1

acti ve agents on water barri er a n d morpholog i c

pa rameters .

Chapter 5: Eczematous ( i rr i tant and a l l ergi c ) reacti ons of the 104

s k i n and barri er fu ncti on as determi ned by water

va pour l os s .

Chapter 6 : The i nfluence of l ow concentrati ons of i rr i tants on 121 sk i n barr i er function as determi ned by water vapour

l os s .

Chapter 7 : S k i n i rr i tancy of commerc i ally ava i l abl e soap and 1 29

detergent bars as measured by water vapour los s .

Cha pter 8: Summary and conc l us i on s .

Samenvatt i ng en conclu s i es .

Acknowledgement .

5

142

157

I ntroduction

I n severa l epidem i o l og i ca l stud i es on s k i n d i seases , eczema was found

to be the most important d i agnos t i c ca tegory .

Eczema can be c l as s i f i ed i nto ma ny types . These c l a s s i f i cati ons are

based on combi nat i ons of morphol og i ca l , eti ol og i ca l and consti tuti onal

features . In contact derma titi s externa l factors are ass umed to p l ay

a domi nant rol e i n the etio l ogy and can be c l a ss i fi ed as fol l ows :

- Acute tox i c contact derma t i t i s

- I rri tant contact dermati ti s

- Al l erg i c contact dermati ti s

- Phototoxi c contact dermati t i s

- Photoa l l erg i c contact dermat it i s .

Al l erg i c contact dermati t i s i s based on an immunol og i ca l phenomenon i n

wh i c h the s k i n reacts hypererg i ca l ly to a substance after prev i ous con­

tact wi th that substance .

I rr i tant contact dermati ti s i s a term used to descri be a non- immunol o­

gi ca l i nfl ammat ion of the sk i n , whi ch i s due to the i nfl uence of one

or more externa l factors .

The data ava i l ab l e at date i nd i cate that i n the major i ty of the cases

of contact dermati t i s i rr i tant factors p l ay a promi nent rol e .

I rri tant contact dermati t i s may show a n acute , subacute or chron i c

course . I n the chron i c type , the eczema i s mostly not caused by one

i rri tant factor but is cons i dered to be the resu l t of many damag i ng

factors . These factors may be of chemi ca l , phys i ca l or b i o l ogi cal ori g i n .

I rri tant factors may i mpai r the s k i n barr i er wi thout c l i n i ca l ( vi s i b l e )

effects upon the ski n . These effects o n the s k i n barrier have been shown

to be cumu l a t i v e .

I t i s hypothes i zed that s k i n barri er i mpai rment may pl ay a cruci a l rol e

i n the devel opment of chron i c i rr i tant contact dermat i ti s .

Among other methods , s k i n wa ter vapour l oss measurements have been used

to eva l uate s k i n barr i er funct i on i mpa i rmen t . Wi th thi s method the i n­

crease i n s k i n wa ter vapour l os s i s cons i dered as an i nd i cati on of s k i n

barr i er defi c i ency .

The method of s k i n wa ter vapour l oss measurements may be appl i ed i n the

6

fo l l owing ways :

- For the assessment of the effect of i rri tants upon s k i n barri er func­

t ion . Th i s is espec i a l ly rel evant for surface acti ve agents wh i ch are

known to have a profou nd effect upon the s k i n barr i er , wh i ch to a

grea t extent may para l l e l the s k i n i rri tancy of these substances .

Cumu l ati ve effects of repeated exposure upon the s k i n barr i er and the

course of barr i er repa i r in t ime can be eva l ua ted .

- After s tandardi zed exposure of the s k i n to one or more i rri tant fac­

tors, i n ter i nd i v i dua l d i fferences in i mpa i rment of the barri er func­

t ion may be as sessed . I f barr i er functi on is i ndeed dec i s i ve in the

deve l opment of chron i c i rri tant contact dermat i ti s , these d i fferences

may pl ay a cruci a l rol e i n i nteri nd i v i dua l d i fferences i n suscepti b i ­

l i ty t o i rr i tants and consequent ly i n suscepti b i l i ty to deve l o p

chron i c i rr i tant contact dermati ti s .

- The course of s k i n d i seases wi th concomi tant d i s turbances of barri er

functi on can be mon i tored by s k i n water va pour l os s measurements .

I n the seri es of s tudi es , presented i n thi s thes i s , an attempt was made

to contri bute to the f i r st two a ppl i cati ons .

7

CHAPTER 1

THE BARRIER FUNCTION OF THE SKIN AGAINST DIFFUSIONAL WATER LOSS

8

The barr i er functi on of the s k i n aga i nst d i ffu s i onal water l oss

Tota l water l oss

Di ffus i onal water l os s

cutaneou s l oss o f water ( vapour and dropl ets )

v i a pas s i ve d i ffu s i on through the epi derm i s

and by sweat g l and act i v i ty ;

water l os s through the s k i n by d i ffu s i on ,

emphas i z i ng the pas s i ve nature of th i s

process;

Transepi derma l water l os s water l os s through the s k i n by d i ffus i on ,

emphas i z i ng the l ocati on of the barr i er ( a

more prec i se but not frequently used term

wou l d be transcornea l water l os s ) .

An important func t i on of the s k i n i s i ts barr ier nature wh i ch protects

the body aga i nst the entry of fore i gn matters a nd prevents the l os s of

essent i a l substances l i ke water . Th i s protect i v e fu nct i on has been known

for centu r i es . Unti l the twent i eth century , the s k i n was genera l l y

regarded as bei ng impermeab l e to a l l substances , except perhaps for

vol ati l e substances and gases (1 , 2 ) . Ma i n ly through work done by

Schwenkenbecher at the turn of the century , the fa l l acy of the compl ete

impermeab i l i ty of the s k i n was gradua l l y d i spel l ed ( 1 , 3 ) .

H i s exper iments revea l ed that the s k i n i s permeabl e to substances wh i c h

are sol ub l e i n l i p i ds and to those i n t he gaseous state , b ut i s

pract i ca l l y impermeab l e to water and e l ectro l ytes . S i n ce that t ime , the

barri er fu nct i on of the s k i n has not been cons i dered to be absol ute ,

a l though i t can norma l l y be rel i ed on to protect agai nst mu l t i pl e

env i ronmenta l s tresses ( 4 ) .

The anatomi ca l bas i s of the barr i er agai nst cuta neous d i ffus i onal water

l oss

The preci se l ocat ion of the s k i n l ayer const i tuti ng the mai n barri er has

been a prob l em for many years . Based on t,i s experi ments , Rei n concl uded

i n 1924 that an el ectri cal dou b l e l ayer s i tuated between the stratum

corneum and the Ma l pi gh i an l ayer i s respons i b l e for the l ow permeabi l i ty

9

of the s k i n to i ons ( 5 ) . Others i dent i f i ed the stratum l u ci dum as the

ma i n barri er ( 6 ) .

The stratum l uc i dum , however , was not a l ways present i n the i nvesti gated

s k i n ( 2 ) . Th i s l ayer was detected w ith certa i nty only i n the s k i n of the

pa l ms of the hands and sol es of the feet . For th i s reason , Rothman i n

1932 proposed that the trans i t i onal l ayers between corni f i ed and noncor­

ni f i ed epi dermi s shoul d be rega rded as the s i tes of impermeabi l i ty for

el ectrol ytes and water , wi thout spec i fying the h i sto log i ca l nature of

the trans i t i onal l ayers ( 2 ) .

As early as 1944 , Wi nsor and Burch p i npoi nted the stratum corneum as the

barri er aga i nst d i ffu s i onal water l oss ( 7 ) . This conc l u s i on was hard l y

accepted a t that t ime . Rothman ( 1 954 ) draw attenti on t o the great avi ­

d i ty w ith wh i ch the human horny l ayer takes up water from ei ther s i de ( 8 ) .

The horny l ayer was cons i dered as a porous membrane through wh i ch i ons

and l arge mol ecul es move rapi d l y . Th i s theory arose from the c l i n i ca l

p i cture o f many s k i n d i seases . The cus tomary h i stol og i ca l techni que of

prepar i ng and vi ewi ng the s k i n i n transverse secti on a l so contri buted

to th i s fau l ty i dea ( 1 ) . Ma l i ( 1 955 ) cons i d ered the stratum corneum as

a porous structure on ly s l i ght ly imped i ng the passage of water mo l ecul es

and concl uded that the l ayer wh i ch determi nes the barr i er for water i s

the barri er zone between the l i v i ng cel l s o f the stratum spi nosum and

the dead corn i f i ed stratum corneum ( 9 ) .

The adhes i ve stri pp i ng technique u s i ng cel l ophane tape to remove th i n

l ayers of stratum corneum offered a way to l ocate the barri er zone more

prec i sely ( 1 , 10 , 1 1 ) .

Us i ng th i s method , Bl ank ( 1952 ) concl uded that the stra tum corneum i s

the rate l i mi t i n g barri er for transepi dermal water l oss ( 12 ) . I n a

seri es of i nvesti gati ons , he made i t c l ear that repeated stri ppi ng i n­

creased water di ffu s i on very l i ttl e unti l the base of the stra tum corneum

was reached . Al though he was aware of the defi c i ences of the stri ppi ng

method , he came to the concl us i on that not the enti re corn i fi ed epi the­

l i um but a very th i n l ayer near the base of the stratum corneum formed

the maj or barr i er aga i ns t d i ffu s i ona l water l oss ( 13 ) .

Th i s l ayer , the stratum corneum conj unctum o r Szaka l l l ayer ( 14 ) , was

thought to be the rea l barr i er of the s k i n aga i nst water l os s for many

10

years . Monash and B l a n k ( 1 958 ) , al so us i ng the s tri ppi ng tech n i que wi th

cel l ophane adhes i ve tape , found that the water barri er cons i sted of the

i nner two-t h i rds of the s tratum corneum ( 1 5 ) . In 1 965 , B l a n k recons i dered

h i s resu l ts and came to the conc l u s i on that h i s data cou l d equa l l y we l l

be i nterpreted as implyi ng that the bu l k of the horny l ayer was u n i form ly

impermeab l e ( 1 , 4 ) . The concept of a un i form horny l ayer as the ma i n sk i n

barri er has been confi rmed by stud i es on the l ocation of substa nces

wi th i n the t i ssue some t ime after appl i cati on . The l a rgest amount has

a l ways been fou nd i n the outer l ayers and to decrease proporti onate ly

towards t he base ( 1 ) .

E l ectron mi croscopy has revea l ed the structure of the stratum corneum to

be a compact mu l t i l ayered ti ssue i n wh i ch the cel l s are i nterd i g i tated

and the i nterce l l u l ar spaces are fi l l ed . The el ectron mi crogra phs suggest

that a l l strata of the horny l ayer are equa l ly effect i ve , perhaps w i th

the excepti on of the one adj acent to the granu l ar l ayer , which may be

s l i ght ly more permeab l e because it is not yet fu l l y corn i f i ed , and the

outermost l ayers whi ch may be break i ng up and bei ng s hed ( 4 ) .

Al though not genera l l y accepted , t h i s v i ew has been acknowl edged by many

authors ( 1 4 , 1 6 -2 1 ) . The horny l ayer however i s not the s o l e obstac l e to

i nward passage . The skin can be cons i dered as a sys tem of mu l ti pl e com­

pa rtments , a l l wi th the i r rate l im it i ng propert i es . I n heal thy s k i n ,

the stratum corneum i s deci s i ve for the tota l permeabi l i ty ( 17 , 22 ) .

For some substances , especi a l ly i f the horny l ayer i s defi c i ent , other

barri ers may pl ay a part ( 23 , 24 ) . Thi s has no impl i cati ons for the

i nvest i gati on of water l os s , because the horny l ayer prov i des the only

barri er for thi s .

The water l oss from stri pped s k i n ( horny l ayer removed ) i s about the same

as the water vapou r l oss at a water surface ( 1 3 , 25 ) .

11

Tab l e 1 . Rates of water vapour l oss from the surface of the forea rms as

reported by d i fferent i nvest igators .

Authors Method Cutaneous water vapour l os s ( g;m2h )

Gasse l t & V i erhout venti l ated chamber (dr i ed a i r ) ( 1963 ) ( 2 6 ) not standardi zed

Ohara & Ono ( 1963 ) ( 2 7 )

Spru i t & Ma l ten ( 1965 ) ( 2 5 )

Th i e l e & Senden ( 1966 ) ( 2 8 )

Ba ker & Kl i gman ( 1967 ) ( 2 2 )

Shah i du l l ah e t a l . ( 1 967 ) ( 2 9 )

Johnson & Shuster ( 1 969 ) ( 30 )

S ha h i du l l ah et a l . ( 1 969 ) ( 3 1 )

Lamke & Wed i n ( 197 1 ) ( 3 2 )

Lamke et a l . ( 197 6 ) ( 33 )

d e Jongh ( 1981 ) ( 3 4 )

u nventi l ated chamber neutral therma l cond i t i ons

venti l ated chamber ( d r i ed N2 ) not standard i zed

venti l a ted chamber (dr i ed N ) d i fferent envi ronmental con3 i t i ons

venti l ated chamber ( dri ed a i r ) ant icho l i nerg i c suppres s ion

unventi l a ted chamber not sta ndard i zed

venti l ated chamber ( d r i ed N2 ) anti chol i nerg i c suppress i on

venti l a ted chamber (dr i ed N2 ) a nti chol i nergi c suppres s i on

venti l ated chamber (moi s tened a i r ) neutral amb i ent cond i ti o ns

gradi ent estimat i on not s tandard i zed

venti l ated chamber ( dr i ed gas ) not s ta ndard i zed

12

4 , 8 - 9 , 0 ( ra nge )

12 , 7 (mea n )

8 , 8 � 3 , 7 (mea n and S . E . )

1 , 8 - 15 ( ra nge )

3 , 1 � 0 , 6 (mean a nd S . E . )

0 ,84 - 4 ,65 ( range )

3 , 5 � 0 , 4 (mean a nd S . E . )

1 , 9 - 6 , 4 ( ra nge )

1 2 , 3 � 1 , 4 (mea n and S . E . ) "

3 - 11 ( range )

+ 4 , 6 - 1 , 5 (mean and S . E . )

The bi ochem i cal bas i s of the s k i n barri er aga i nst cutaneous d i ffus i onal

water l oss

Probabl y , a l l major bi ochem i cal cons ti tu ents of the horny l ayer con­

tri bute to the i ntegri ty of the s k i n barr i er aga i nst transepi derma l

water l oss ( 3 5 ) . The rel at i ve importance of l i p i ds , prote i ns and carbo­

hydrates i n l i m i t i ng water l os s by evaporati on has , however , been debated

( 3 5 , 36 ) . The importance of kerat i n , i ntracel l u l ar and i ntercel l u l ar

l i p i ds and water sol u b l e substances has been emp ha s i zed ( 9 ,36-41 ) . I t

has a l so been postu l ated that not the absol ute quant i t i es o f horny l ayer

components but the compl ex i nterrel ati ons h i p between them i s i mportant

for the s k i n barr i er capac i ty ( 42 ) .

Primari l y prote i n , the ma i n component of the horny l ayer ( Tabl e 2 ) , was

cons idered as bei ng ch i efly i nvol ved i n l i m i t i ng evaporative water l os s ,

espec i a l l y the t i ght network of kerati n f ibres ( 38 , 40 ) . However , kerat i ­

nolyt i c agents were found to have n o or onl y s l i ght effects o n the water

barri er of the s k i n ( 43 , 44 ) . If the barri er was mos tly prov ided by the

kerat i n mo i ety , one wou l d expect a d i rect correl at ion between the th i ck­

ness of the horny l ayer and transepi dermal water l os s ( 41 ) . However , the

thi ckness of the horny l ayer and d i ffu s i onal water l os s correl ate poorly

( 45 ) . The t h i c kness and water d i ffu s i veness seem to compl ement each other

l ead i ng to rather constant permeabi l i ty ( Tab l e 3 ) . These reg i onal d i ffe­

rences i n permeabi l i ty cannot be expl a i ned on the bas i s of d i fferences

i n the chemi cal nature of the kerat i n mol ecu l e1 ( 40 ) . Al though there i s

ev i dence that the structural protei ns of the cytopl asm and the cel l

envel ope p l ay a part i n the barri er funct i on . The rol e i n l i m it i ng

transepi derma l water l os s i s rel at i vely sma l l ( 36 ) .

The centra l rol e of l i p i d s i n regu l at i ng transepi derma l water l oss has

been demons trated by many i nvesti gators ( 13 , 3 6 , 3 9 , 41 -44 ,46 ,47 ) . The

greatest i ncrease in d i ffus i ve water l os s was found after treat i ng the

1 . Reg i onal var i at i on in horny l ayer l i pi ds i s more l i kely to be respon­s i b l e for d i fferences in permeab i l i ty ( Tab l e 4, p . 20 ) .

1 3

Tab l e 2 . Consti tuents of human dry corn i f i ed epithel i um . _[ro� Mato l tsy

& Bal samo (1955) ( 93) .

So l ub l e epi derma l kerati n :t 10 %

D i a lyzab l e substances !" 10 %

Epi derma l kerati n :t 65 %

L i p ids 7 -9 C{ ,,

Res i stant cel l membranes :!; 5 %

Tab l e 3 . Regi onal var i at i on i n water permeabi l i ty

p l ei n & B l a n k ( 1 9 7 1 � (45).

S k i n reg i on Js c5 om

Abdomen 0 . 34 15 . 0 6 . 0

Vol ar forearm 0 . 3 1 1 6 . 0 5 . 9

Back 0 . 29 10 . 5 3 . 5

Forehead 0 . 85 13 . 0 12 . 9

Scrotum 1 . 70 5 . 0 7 . 4

Back of hand 0 . 56 49 . 0 32 . 3

Pa lm 1 . 14 400 535 . 0

P l antar so l e 3 . 90 600 930 . 0

Js steady state f l ux of water (mg cm- 2hr- 1 )

o th i c kness of the horny l ayer (em x 10-4 )

D = d i ffus i on constant ( cm2sec- 1 x 10- 1 0 ) m

14

at 30°C . From Scheu------

s k i n w i th del i p i d i z i ng sol vents . Other exper imenters cou l d not confi rm

the importa nce of l i p i d extract i on for barr i er function ( 38 ) . Th i s

d i screpancy may be exp l a i ned by the fact that b r i ef immers i on i n or

appl i cat i on of l i p i d sol vents only removes superfi c i a l l i p i d s , proba b ly

un i mporta nt for barr i er funct ion ( 38 ) . Moreover , l i p i ds compl exed w i th

prote in s and carbohydrates and protected by a hydroph i l i c zone prevent i ng

the so l vents from reach i ng the l i p i d s are not sol u b l e i n very nonpo l a r

sol vents ( 39 ) . These compl ex l i p i ds c a n be extracted more effecti vely by

a combi nat ion of pol ar and nonpo l a r sol vents ( 45 ) . I t i s a l so sugges ted

that water extract i on after del i p i d i zati on removes pol ar substances i m­

portant for barr i e r funct i on i f unprotected by l i p i d s { 1 3 ) .

Not a l l horny l ayer l i pi ds are equa l ly i mportant for barr i er capaci ty

( 3 5 ) . Recent s tud i es i nd i cate that essenti a l fatty ac id s may be part i cu­

l a r ly i nvol ved i n the i nteg r i ty of the water barri er of the s k i n ( v i de

i nfra ) .

The rol e of stratum corneum hydrat ion i s a l so emphas i zed ( 2 1 , 3 7 , 38 , 48-

50 ) . The water b i nd i ng capac i ty of the corneocyte i s attri buted to

fi brou s protei n and water sol u b l e substances wi t h i n the cel l i n add i t i on

to the osmoti c funct ion of the cel l membrane ( 2 1 , 38 , 48 , 49 ) . I t i s sugges­

ted that bou nd water mol ecu l es form a barr i er aga i n st d i ffus i ng free wa­

ter mol ecu l es ( 49 ) .

I f the horny l ayer cel l s have a defi c i ent water b i nd i ng capa c i ty , e . g . ,

due to damage to the cel l membranes , th i s may l ead to both hydrat i on and

i ncreased d i ffus i ve water l os s ( 2 1 , 3 7 ,48 , 49 ) . The barr i er funct ion i s

a l so i mpai red i n the case of exces s i ve hydrat i on ( 48 , 49 ) . 'Pores' may be

opened by t h i s exces s i ve hydrat i on through wh i c h d i ffus i on of water may

be faci l i tated ( 49 ) .

The essenti a l fatty a c i d component of horny l ayer l i p i ds

Both the l i p i d wei g ht percentage and the compos i t i on of the l i p i d s of

the horny l ayer a re importa nt for the barri er funct ion of the s k i n

( 46 , 51 , 52 ) . Topograp h i c var i a t i on i n permeabi l i ty can b e l argely

expl a i ned by quant i ta t i ve d i fferences i n l i p i d content ( 46 ) .

Recentl y , part i cu l ar a ttent ion has been devoted to es senti a l fatty ac i d

1 5

components of the stratum corneum l i p i d s . I t has been demonstrated that ,

i n essent i a l fatty aci d defi c i ent rats and humans , qual i tat ive di ffe­

rences i n l i p i d compos i t i on i n compar i son w i th norma l s can a l so be found .

The def i c i ency i s refl ected i n abnorma l fatty ac id moi et i es i n epi derma l

phospho l i p i d s wh i ch correl ate with ma rked barr i er funct i on impai rment

wi th respect to wa ter ( 52-56 ) .

Top i ca l appl i cati on of sunfl ower seed o i l (whi ch i s ri ch i n l i no l ei c

aci d } proved to l ower the rate of transepi derma l water l oss i n these

essent i a l fatty ac id defi c i ent rats and huma ns ( 39 , 53 ) . It has been

shown that sunfl ower seed oi l rapi d l y restores the h i gh rates of trans­

epi dermal water l oss of sk in treated w ith a so l u ti on of sod i um l aurate

( 54 ) . Th i s water retardent property of sunfl ower seed oi l proved to be

the res u l t of its h i g h content of l i no l ei c ac i d . Al though other

cutaneous ly appl i ed fatty aci d tr ig lyceri des are a l so metabo l i zed and

i ncorperated i nto the comp l ex l i p i ds of the s ki n , only l i no l e i c- and

y- l i no l e n i c ac id restore the barri er functi on ( 55 ) . It is concl uded

that d i fferent fatty ac ids may have vary i ng roles i n the epidermis ,

l i nol ei c ac id bei ng parti cu l ar ly i nvol ved i n the i nteg r i ty of the water

barri er ( 3 5 , 56 ) .

However , i t has been demonstrated that the water retardent property of

l i no l e i c acid is not compound spec i fi c , s i nce several syntheti c , d i enoi c ,

transconfi gurated fatty aci ds can substi tute for l i neol ate ( 57 ) . The

questi on of wh i ch stratum corneum l i pi d s refl ect the abnorma l i ty of

barri er functi on rema i ns to be answered ( 52 ) .

L i nol e i c ac id compri ses only a mi nor fracti on of horny l ayer fatty ac id

moi et i es ( 58 ) a nd l i p i ds conta i n i ng esteri fi ed l i no l e i c a c i d may p l ay

a rol e ( 52 ) .

Modern v i ew of subce l l u l ar horny l ayer orga n i zati on : a two-compartment

mode l

Di fferent model s have been proposed t o expl a i n t h e subce l l u l ar organ i za­

t i on of the horny l ayer and thus of the s k i n water barri er (46 , 52 , 59 ) .

Ear l i er model s were based on c i rc u l a r protein cyl i nders coa ted with

l i p i d mol ecu l es ( Fi g . I ) ( 59 ) . The horny l ayer was cons i dered as a

16

Fig . I .

Intracel l u l ar keration in the stratum corneum . From Scheupl ein and B l ank ( 4 5 ) .

•

Fig . I I . Col umnar pattern of the ( huma n ) horny l ayer . From Mackenzie ( 63 ) .

17

Fi g . I I I .

stratum corneum 1�.·.;.::; �:·{:::.·.: � � -· ··· · .: � •t."• .::·· �· • . :� .:.:· \ ... . �· .. . : '.. ..... ·: .. :

components

CORNEOCYTES

IC LAMELLAR L I P I D

brick wall

components

BRI CKS

MORTAR

Current concept of the stratum corneum as a two-compartment system , in

wh ich cel l s can be ana l ogized to bri cks , and i ntercel l u l ar l amel l ae to

mortar . From El i a s et a l . ( 52) .

18

homogeneous sheet of fi bri l s i nters persed w ith a shel l of amph i pati c

l i p i d ( 59 ) . Th i s kerat i n - phosphol i p i d compl ex i ns i de the corneocyte

was presumed to be the major pathway for penetrati on . The i ntercel l u l a r

spaces were d i sm i ssed because o f thei r sma l l volume ( 45 ) . Recent h i sto­

chemi ca l stud i es s how a stratum corneum cel l devo i d of l i p i d and l arge

i ntercel l u l ar spaces f i l l ed mos tly wi th nonpo l a r l i p i ds ( 58-60 ) .

Di rect evi dence has a l so become ava i l abl e that epi cutaneous ly appl i ed

subs tances permeate v i a the i ntercel l u l ar s paces ( 6 1 ) .

I n the stratum granu l osum , the i nterce l l u l a r vol ume i s gross ly d i stended

as a resu l t of accumu l ated l amel l ar body contents ( 59 ) . These l amel l ar

bod i es , a l so ca l l ed membrane-coati ng g ranu l es , Odland bod i es , cementa­

somes or kerati nosomes ( 52 ) , are sma l l bod i es wi th a l ame l l ar s tructure

l ocated in the cel l s of the m i depi dermi s ( 62 ) . In the h i gher epi derm i s ,

they mi grate to the per i phery of the cel l and a re extruded i nto the

i ntercel l u l ar s pace . I n i t i a l l y , much of the substru cture i s reta i ned

after expu l s i on . I n the s tratum granul osum , the l amel l a e rema i n

segregated i nto foca l accumu l at ions of rel ati ve ly pol ar d i scs and matr i x

( 59 ) . I n the horny l ayer , th i s l amel l ar materi a l i s transformed i nto

broad mu l ti l am i n ated i nterce l l u l ar sheets of l i pi ds corre l at i ng w i th a

stri k i ng s h i ft from pol ar l i p i d s ( p hos phol i p i ds ) to nonpol ar l i p i ds

( tr i g lycer i des , free s terol s , free fatty ac i ds , sterol esters ) ( 5 1 , 5 2 ,

58-60 ) ( Ta b l e 4 ) .

These f i nd i ngs are expres sed i n the hypothes i s depi cti ng the s tra tum

corneum as a two- compa rtment system of l i pi d depl eted cel l s surrounded

by l i p i d enri ched cel l u l ar doma i ns ( 52 ) , mos t ly organi zed i n a col umnar

pattern , accordi ng to Mackenz i e ( 1983 ) ( 63 ) ( F i g. I I , I I I ) . I n the

desquamat i ng s tage of kerati n i sat i on , these d i fferences between the

corneocyte and i ntercel l u l ar s pace probab ly d i s a ppear , whi l e corneum

l i pi ds i n the su perf i c i a l s tratum were found to be u n i formly d i stri buted

throughout and between the cel l s ( 64 ) .

The rel at i ve importance of the cel l u l a r and i ntercel l u l a r pathways for

l i pi d sol ubl e and water sol ubl e substances i s u nknown, a l though the

i ntercel l u l a r doma i n is mos t important for the water barr i er capa c i ty of

the horny l ayer ( 52 , 58-60 ) .

19

Tabl e 4 . Reg i onal var iat i on and strati f i cation of human stra tum corneum l i p i d s . lro� E l i a s et a l . (52 ) .

Outer Whol e stratum corneum Stratum Strata

stratum Abdomen P l antar granu l osum basa l e/ s p i nosum

corneum

L i p i d WT { '; ) 6 . 5 : 0 . 5 2 . 0 : . 6 ND ND

Fract ion

Pol ar l i p i d s 2 . 3: 0 . 5 4 . 9 : 1 . 6 4 . 5 : 0 . 4 25 . 3 : 2 . 6 44 . 5 ± 3 . 4

Chol esterol s u l fa te 3.4 : 0 . 5 1 . 5 ± 0 . 2 3 . 4 ± 1 . 2 5 . 2 ± 1 . 4 2 . 6 ± 1 . 0

Neutra l l i p i d s 68 . 4: 2 . 1 77 . 7 ± 5 . 6 63 . 9 : 3 . 6 60 . 9 ± 9 . 1 50 . 0 ± 4 . 5

Free s terol s 1 8 . 4 ± 2 . 1 14 . 0 ± 1 . 1 2 3 . 1 ± 9 . 0 10 . 5 ± 1 . 6 12 . 1 ± 1 . 0 0

Free fatty ac id s 1 5 . 6 ± 3 . 0 19 . 3 ± 3 . 7 N

20 . 0 ± 12 . 3 9 . 2 ± 1 . 5 7 . 0 ± 2 . 1

Tr i g l ycer i des 1 1 . 2 ± 1 . 5 2 5 . 2 : 4 . 6 8 . 5 ± 2 . 2 24 . 7 ± 4 . 0 12 . 4 ± 2 . 9

Nonpol ar Nls 19 . 4 ± 2 . 6 1 6 . 3 ± 6 . 5 1 2 . 3 ± 1 . 2 14 . 3 ± 1 . 1 16.7 ± 0 . 7

Sterol /wax esters 6 . 4 : 1 . 4 6 . 4 ± 1 . 4 6 . 7 ± 1 . 0

Squa l ene 3 . 8 ± 1 . 6 4 . 6 ± 1 . 0 5 . 9 ± 0 . 9

n-Al kanes 2.1 ± 0 . 7 3 . 3 ± 0 . 8 4 . 1 ± 0 . 3

Sphyngol i p i d s 26 . 6 2 . 3 1 8 . 1 2 . 8 30 . 1 ± 6 . 3 1 1 . 7 ± 2 . 7 7 . 3: 1 . 0

G lycol i p i d-! 2 . 7 1 . 4 2 . 9 3 . 2 2 . 0

G l ycol i p i d - 2 2 . 7 0 . 5 1 . 1 1 . 4 1 . 5

Ceram i des 7 .l 1 2 . 4 19 . 6 4 . 1 1 . 7

Ceram i des/Nls 7 .l 3 . 8 6 . 2 2 . 9 2 . 1

The phys i o l ogical bas i s of cutaneous water l oss

Tota l wa ter l oss from the skin has been trad i t i ona l l y d i v i ded i nto a

v i s i b l e l oss of water by sweat g l and act i v i ty a nd macros cop i c i nv i s i b l e

water l oss from " pers p i rat io i nsens i b i l i s " ( 8 , 6 5 ) . Th i s nomencl ature has

the shortcom i ng that it does not i nd i cate the ori g i n of the water l os s of

the s k i n . Moreover , qu i te l a rge quanti t i es of water l osses from , e . g . ,

the palms of the hand , may be i nv i sibl e ( 7 , 8 , 66 ) .

I n fact , the ma i n sources of cutaneous water l os s are the sweat g l ands

and the conti nuous fl ow of water through the epi dermi s , the l a tter cal l ed

by Rothman ( 1954 ) transepi derma l water l os s ( 8 ) . Mi nor sources of water

l os s may be desorpt i on of the horny l ayer cel l s ( after bei ng hydrated ,

e . g . , by sweat ) and dehydrat ion of cel l u l ar protopl asm during kerat i n i ­

zation (8 , 2 2 , 67 ) . Water l os s through sebum may be negl ected , as th i s

l oss i s very sma l l and on ly about 1 m l per day ( 68 ) . Water l oss v i a the

pi l osebaceous uni t may be i mportant , a l though i t s surface area i s very

sma l l i n compari son wi th the unbroken stratum corneum ; the l arger shunt

d i ffus i veness of water is more than compensated for by the muc h sma l l er

effecti ve area of the shunt pathway ( 1 , 16 , 69 , 70 ) .

On the bas i s of these facts , many i nvesti gators attri bute total water

l oss from the s k i n to a fl ow through the stratum corneum ( transep i dermal

water l os s ) and a f l ow through the sweat g l and a s vapour or as dropl ets

( 7 , 8 , 66 , 67 ) . Transepi dermal water l oss is descri bed i n terms of d i ffu s i on

through the "membrane- l i ke " s tructure of the horny l ayer and i ts appen­

dages , i nc l ud i ng the sweat g l and epi thel i um ( 66 ) .

The sweat g l and i s con s i dered as a functi onal un i t neura l ly acti vated

by acety l chol i ne ( 66 , 6 7 ) .

Transepi dermal water l oss

Transepi derma l water l oss can be cons i dered as a fl ow by d i ffu s i on

through the s tratum corneum structure , based purely on phys i cochemi cal

l aws ( 35 , 7 1 , 7 2 ) . It has been suggested that water i s acti vely transported

i nto the s k i n ( 1 , 69 , 73 ) . Acti ve transport of water , however , seems very

un l i ke l y . The water barr i er functi on i s essenti a l l y the same i n v i vo and

2 1

i n v i tro and i s mai ntai ned l ong after the s k i n i s removed from the body

( 73 , 7 4 ) . The stratum corneum , mai nly res ponsib l e for the d i ffu s i onal

res i s tance , cons i sts of h i g h l y d i fferent i a ted but metabol i ca l ly i nacti ve

ti ssue ( 3 5 , 7 2 ) . The physi cochem i ca l l aws of pa s s i ve d i ffu s i on are l argely

obeyed ( 1 , 3 5 , 69-72 ) .

Pa s s i ve d i ffu s i on can be descri bed by F i c k ' s l aw:

J s amou nt of water per u n i t area and t ime

transported throu gh the stra tum corneum

Kp permeabi l i ty constant

6Cx d i fference i n concentrat ion on both

s i tes of the stratum corneum

Th i s equation can be ex panded i n ( 6 9, 7 5 ) :

part i t i on coeff i c i ent ; i n the case of

water , the sol ub i l i ty coeff i c i ent

d i ffu s i on coeff i c i ent

th i ckness of the stratum corneum

The proport iona l i ty of vapour l os s to vapou r pressure i s wel l establ i shed .

Thus , F i ck ' s l aw can a l so be wr i tten a s ( 7 5 , 7 6 ) :

6R.H. = d i ffere nce i n rel ati ve hum i d i ty on

both s i des of the stratum corneum .

The rel at i ve humi d i ty on the i nner

face of the stratum corneum can be

con s i dered as 100 ( 22 ) .

This equat i on means that , i f the horny l ayer behaves l i ke an i deal mem­

brane , the trans fer of water i s dependent u pon amb i ent humi d i ty and the

t h i ckness a nd membrane qual i t i es ( i nteg r i ty ) of the horny l ayer ( 1 2 ) .

F i c k ' s l aw proved appl i cabl e a s far a s proport i onal ity w ith the th i ckness

of the horny l ayer is concerned ( 4 , 1 6 , 22 ) . The proportional ity with the

d i fference i n re l at i ve hum i d i ty , however , does not perfectly fit the l aw

of F i c k . The l os s of d i ffu s i ve water decreases when the ambi ent humi d i ty

i ncreases , but not to an extent that wou l d be expected on the bas i s of

F i c k ' s l aw ( d i fference i n re l at i ve hum id i ty decreases i f amb i ent hum i d i ty

i ncreases ) ( 77 ) . The i ncrease i n permeabil i ty for water at h i g h environ­

mental humi dity can be explained by a bsorption of water . The higher water

content of the horny l ayer a l ters the permeabi l i ty constant of the s k i n ,

22

Tab l e 5 . Permeab i l i ty of water through monol ayers , fi lms , cel l u l ar

membranes and i ntegument . From_2�heu p l e i n & B l a n k ( 1 971" ) (45) .

Mono l ayers

Thi ckness , Permeab i l i ty em . Constant

em/ sec .

C l ean wa ter i nterface 3 x 10- 8

Long-cha i n a l i phat i c a l cohol 2 x 10- 7

monol ayer at a i r-wa ter

5 X 1 02

( 1- 2 ) X 1 0- 1

i nterface

Phosphol i p i d b i l ayer

( tetra decane l ec i th i n )

F i lms

Stagnant water l ayer

My l a r

Tef lon

Saran

Ce l l u l ar membranes

Human erythrocytes

Human l eucocytes

F i brob l a sts i n t i s sue

Arbac i a eggs

I ntegument

Frog s k i n

cu l ture

Human stratum corneum

Human derm i s

- 7 - 4 6 . 1 X 10 3 . 3 X 10

2 . 0 X 10- 3 1 X 1 0-2

2 . 0 X 10-3 1 . 5 X 10- 7

2 . 0 X 10-3 3 . 1 X 10-8

2 . 0 X 10-3

2 . 0 X 10-8

5 . 0 X 10- 7 1 . 3 X 10-2

1 X 10-6 2 . 8 X 10-3

1 X 10-6 6 . 2 X 10- 3

( 2- 8 ) X 10-4

7 X 10 - 5

2 X 10- 3 2 . 5 X 1 0- 7

4 X 10- 1 5 X 1 0-6

23

D i ffu s i on Constant cm2/ sec .

1 . 5 X 10- 5

( 2- 4 ) X 1 0-8

2 . 5 X 10- 5

3 . 0 X 10- 10

6 . 2 X 10- 1 1

4 . 0 X 10- 1 1

6 . 5 X 10-9

2 . 8 X 10-9

6 . 2 X 10-9

5 X 10- 1 0

2 X 10-6

resul ting in facil itation of water pas sage ( 77 ) . I t shou l d be noted that

skin diffusion constants may vary from one s kin region to another ( Ta bl e

3 ) { 6 ) . The diffu sion constants are a l so a refl ection of constitutiona l

and environmental factors ( 78 , 79 ) .

Sweat g l and activity

Human sweat g l ands are described as merocrine and are usual ly divided

into apocrine and eccrine sweat g l ands ( 80 ) . This division has been

criticized because apocrine secretion is not substantiated in human

beings ( 80-82 ) . It has been shown that during apocrine sweating the

apices of the secretory cel l s are not s hed , but sma l l portions of apica l

cytopl asm are pinched off ( 82 ) . I t is proposed to use the description

epitrichia l for apocrine swea t g l and s , since they norma l ly devel op from

the externa l root sheath of the hair fol l ic l e , and atrichia l for eccrine

sweat g l ands , because they have no re l a tion with the hair fol l ic l e .

Atrichia l ( eccrine ) sweat g l ands devel op from the superficia l epidermis

and remain independent from the hair fo l l ic l e ( 80 , 83 ) .

The epithrichia l ( a pocrine ) sweat g l ands are common ly found in the

axil l a , the perianal region and the areo l a of the breasts , a l though

ectopic g l ands may be found e l s ewhere on the body surface ( 80 ) . It may

be concl uded that epitrichial sweat g l ands , except for the axi l l ary

region , have a l imited physiol ogical funct i on ( 84 ) . Because of these

facts , the contribution of the epitrichia l sweat g l and to skin water l os s

c a n b e neg l ected .

The atrichia l (eccrine) sweat gl and in man

The sweat g l and activity in man is quite variabl e and is regu l ated by

central sudo-motor activity , l ocal conditions and hormona l factors ( 85 ) .

Both differences in sweat g l and density and activity of the individual

sweat g l and a re responsib l e for regional differences in sweat g l and

production ( Tab l e 6) ( 8 , 80 , 85 ) . Variations in sweating due to sex , race

and age have a l so been reported ( 8 , 85 ) . Racial differences in sweat

g l and density have been observed . These differences probab ly refl ect

24

Tabl e 6. D i s tr i but i on of eccr i ne g l ands i n man (per square i nch of

surface area ) . From Rothma n (1�54) (8) .

Pa l ms

Sol es

Dorsa of hands

Forehead

Chest and abdomen

Forearm

f l exor as pect

2 . 736

2 . 685

1 . 490

1 . 2 58

1 . 136

1 . 123

extensor aspect 1 . 093

Dorsa of feet

T h i g h and l eg

med i a l as pect

l ateral as pect

Cheek

Nape of neck

Back and buttocks

25

0 . 924

0 . 576

0 . 554

0 . 548

0 . 41 7

0 . 41 7

an adaptat i on phenomenon to hot c l imates rather than bei ng ba sed on

genet i c d i fferences { 8 , 85 ) .

The onset of swea t i ng i n response to heat becomes more del ayed wi th age

i n ma l es , wherea s i n fema l es the del ay t ime i s grea te�in adu l t l i fe

{85 ) .

The funct ion of the atr i c h i a] sweat g l and i s dependent on an i ntact

sympatheti c nerve supp ly . Denerva t i on l eads i n i t i a l ly to a fast

functi onal arrest wi thout h i sto l og i ca l changes ( 86 ) . Central acti vati on

occurs by therma l , menta l and gustatory s t i mul i from hypotha l am i c and

cort i ca l centres ( 8 , 80 , 85 ) . The efferent pathways i nvol ve nerve fi bres

synaps i ng i n the medu l l a , l a teral horn of the sp i na l cord and sympathet i c

gangl i a . The postgang l i on i c nerve fi bres a re phys i o l og i ca l ly and

anatomi cal ly sympathet i c , but pharmacol og i ca l ly parasympatheti c ( 85 ) .

The nerve end i ngs wh i ch exc i te the atr i c h i a] sweat g l ands l i berate

acetyl chol i ne , i n contras t to a l l other pos tgang l i on i c sympathet i c

fi bres ( 87 ) . Adrena l i n a l so has some effect o n the sweat g l ands , a l though

i ts phys i o l og i ca l rol e rema i ns uncl ear { 88 ) .

Recentl y , a l oose network of catechol ami ne conta i n i ng nerves a round sweat

g l and of monkey paws , whi ch may a l so be present i n man , has been demon­

s trated ( 89 ) . Therma l swea t i ng is control ed by thermoregu l atory centres

i n the hypothal amus wh i ch are acti vated by changes in the temperature

of perfu s i ng b l ood. Afferent st imu l i from the s k i n and cort i ca l impu l ses

may a l ter the acti v i ty of these centres ( 85 ) .

Therma l sweati ng occurs most ly on the s k i n of the face and trunk , but

a l so occurs on the who l e body , i ncl udi ng the palms of the hands and sol es

of the feet ( 80 ) .

The centres control l i ng menta l and gus tatory swea t i ng are not fu l l y known .

There are , however , centres wi th i n the frontal reg i on of the bra i n wh i ch

st imu l ate swea t i ng , espec i a l ly of the pa l ms and sol es , but a l so i n the

axi l l a e , on the forehead or profuse , under i ntel l ectual or emoti onal

i nfl uences . Gusta tory swea t i ng occu rs phys i o l og i ca l l y in many persons

on the l i ps , forehead and nose after eat i ng hot , sp i cy foods ( 8 , 80) .

26

I n h i b i t i on of atri chi a l (eccr i ne) sweati ng

To study transepi derma l water l oss and thus the barri er fu nction of the

horny l ayer , the very vari abl e sweat g l and acti v i ty has to be restr i cted

as much as poss i b l e ( 67 ) . Abol i t i on of sweati ng i s attempted by use of

anti chol i nerg i c compounds such as atrop i ne , pol d i ne methosu l phate and the

scopo l amine ester of hexopyrron i um brom ide ( 8 , 22 , 3 1 ,34 ,67 , 68 ) .

I ndeed , cutaneous evaporati on can be l owered by anti chol i nerg i c drugs

( 90 ) . It is stated that neura l ly contro l l ed swea t i n g i s comp l ete ly

i nh i b i ted by atropi ne ( 88 ) . The questi on , however , i s whether a sweat

gl and sti l l produces water vapour i f i t i s not s t imul a ted . Th i el e et a l .

( 1 981 ) dep i cts the sweat g l and as be i ng equ i va l ent to a "heat p i pe" ( 9 1 ) .

I t i s assumed to function i n thermoregu l at i o n . Water i s secreted by the

fundus of the g l and and evaporates near the base of the duct . The bu l k

of th i s vapour wi l l recondense near the outl et of the g l and and wi l l

return v i a cap i l l ary acti on or by osmos i s . I n th i s way , the sweat g l and

contr i butes cons i derab ly to the thermal regu l a ti on of the body wi th

mi n ima l l os s of water , anal ogous to a "heat pi pe " ( 9 1 ) . (A " heat pi pe"

i s used i n engi neeri ng to transfer heat at h i gh effi c i ency . ) I t i s doubtful whether th i s hydrodynami c f l ow v i a the sweat g l ands can

be b l ocked by top i ca l a ppl i cat i on of anti chol i nerg i c drugs . Spru i t ( 197 1 )

d i d not succeed i n compl etely b l ock i ng th i s s k i n temperature dependent

fl ow by atropi ne i ontophores i s ( 92 ) . Baker & Kl i gman { 1967 ) con s i der

anhydros i s by l oca l a pp l i cati on of ant i chol i nerg i c compounds to be

poss i b l e and obl i gatory i f transepi dermal water l oss i s to be accurate ly

measured . Scopol am i n i zat ion , however , i s not necessary for the greater

part of the trunk and for the l i mbs i f the amb i ent temperature i s 20°C

or l es s ( 22 ) .

27

BARRIER FUNCTION OF THE S KIN AND ITS RELATION WITH IRRITANT

AND ALLERGIC CONTACT DERMATITIS

28

Barri er funct i on of the s k i n and i ts rel at i on wi th i rri tant and a l l erg i c

contact dermati t i s

Horny l ayer forma t i on

By conti nuous cel l prol i ferati on i n the basal l ayer , m i grati on of the

cel l s to the outer l ayers of the s k i n and desquamati on of horny l ayer

cel l s , the s k i n i s prov i ded wi th a constant epi derma l renewa l wh i ch i s

essen t i a l for epi derma l ma i ntenance ( 94 ) .

Through a rate of cel l prol i ferat ion appropri a te to repl ace desquama t i ng

s tratum corneum and a constant exfol i at i ng l evel , the th i c kness of the

ep iderma l l ayers rema i ns cons tant ( 95 ) . Dur i ng the proces s of mi gra t i on

{wh i c h requ i res 52 to 7 5 days ) , i mportant changes occur i n both the

cel lul ar and extracel l u l ar compartments ( 96 ) . The basal cel l , a wel l

hydrated cyl i ndri ca l ce l l , trans forms i nto a rel a t i ve ly dry (wa ter

content of the horny l ayer cel l , 10-20% of the d ry wei ght ) and f l a ttened

polygonal cel l wi th a w idth of� 1 �m and a l ength of� 40 �m ( 3 5 , 97 ) .

The nuc l ei of the v i abl e cel l s of the l ower l ayers of the epi dermi s

d i s i ntegrate i n the outer l ayers of the stratum granul osum ( 98 ) . A dead ,

h i g h ly s tructured , l ayer of� 1 5 cel l l ayers and a w idth of ± 1 5 �m

for mos t of the body regi on s i s formed ( 95 } .

Dur i ng horny l ayer format i on , vert i ca l epi derma l col umns , wh i ch for the

great part of the i r width contact on ly the cel l s immed i ately above and

bel ow are formed . In the horny l ayer , the cel l s of adj acent col umns

overl ap l atera l l y , each cel l i nterd i g i tati n g wi th i ts nei ghbours . Th i s

ordered col umnar arrangement i s parti cu l ar ly pronounced i n the body

reg i on s havi ng a th i n epi derm i s ( 9 4 , 9 9 , 100} . U l t i ma tel y , the cel l s of

the outer l es s dense ly packed l ayers are shed i n d i fferent s i zed

c l u s ters ( 95 ) .

The extracel l u l ar compa rtment a l so undergoes profound a l tera t i ons . I n

the stratum granul os um , the extracel l u l a r vol ume con s i derab ly i ncreases

because of the l amel l ar contents of the membrane-coati ng granu l es ( 59 ) .

These l amel l ar body contents are remodel ed i n to broad sheets of mu l ti ­

l ami nated l i pi ds ( 52 , 59 , 10 1 ) . B i ochem ica l changes i n the extracel l u l ar

l i pi ds ( ca tabol i sm and de novo synthes i s } are con s i dered to be important

for barr i er funct ion and contro l l ed desquamat i on { 51 , 52 , 10 1 ) .

29

I t may be conc l uded that the s tratum corneum i s a very compl ex product

of a renewi ng epi derm i s .

Horny l ayer protecti ve capaci ty and s k i n barr i er functi on impa i rment

The i nteg r i ty of the horny l ayer funct i ons i s determi ned by:

1 ) The d i rect i nflu ence of env i ronmenta l factors of chemi cal , phys i ca l

or b i o l og i ca l ori g i n on the horny l ayer , wh i ch may temporar i l y or more

permanently i nterfere w i t h i ts functi on ( 1 5 , 1 9 , 7 8 , 7g , 1 02- 105 ) .

I t i s poss i b l e that i nterference of a penetrant wi th the comp l ex i n ter­

rel ati onsh i p of horny l ayer components resu l ts i n temporary barri er func­

t i on d i sturbances . These phys i cochem i ca l c hanges may be revers i b l e i n a

few hours { 1 9 , 103-105 ) . Envi ronmental factors may a l so cause more struc­

tu ral damage to the horny l ayer wh i ch may resu l t in more permanent l os s

of barri er functi on ( 7 8 , 79 ) . T h e dead horny l ayer i s not abl e to restore

th i s funct i on and must be repl aced by a new l ayer of epi derma l cel l s be­

fore compl ete protect ive capaci ty i s rega i ned ( epi derma l renewa l ) . If the

damage i s l im i ted to the stratum corneum t h i s proces s wi l l take a few

days ( 19 ) .

An externa l factor ( e . g . the effect of a degrea s i ng agent ) impa i r i ng bar­

rier funct i on wi l l a l so decrease the capac i ty of the s k i n to l im i t the

l oss of water throug h the ep idermi s ( 2 5 , 106-108 ) .

I f the horny l ayer i s severel y damaged , a para keratot i c l ayer i s formed

wh i ch restores the barri er functi on for water very qu i ck ly ( 2-3 days ) .

Th i s l ayer i s mechan i ca l l y i nsuff i c i en t . Normal kerat i n i zat ion after the

format i on of the temporary barri er total regenerati on of the barr i er wi l l

requ i re about two weeks ( 1 9 , 25 , 106 , 109 , 1 10) .

Experimental exper i ences wi th l es s severe i nj u r i es to the s k i n demonstra­

ted that the restorati on of the barri er funct ion aga i nst water fol l ows a n

exponenti al course i n t i me . I f, however , a nother external factors impa i rs

the barr i er funct ion for water before the s k i n barri er i s comp l ete ly re­

covered, the effects prove to be cumu l at ive ( 7 8 ) ( F i g . IV) .

T h i s impl i es that the s k i n barri er may be i mpai red by var i ou s external

factors to such an extent that the s k i n i s not ab l e to prov i de for a hor­

ny l ayer of suffi c i ent barr i er capac i ty ( 7 8 , 79 ) . Th i s may resu l t i n per­

manent barri er funct i on impai rment and permeat i on of substances wi l l be

30

log

barrier

Impairment Clinical disease

1" 2"

' '

' '

3' 4"

' ---

' '

' '

' '

' '

' '

'

days

Fig I V . Cumu l at i ve barr i er funct ion i Mpa i rment due t o d i fferent i n­

fl uences u l t imately l ead i ng to c l i n i ca l d i sease . Freely

adapted from Ma l ten ( 1981 ) ( 7 8 ) .

3 1

enhanced . Subcornea l l ayers of the epi dermi s and derma l structures

may be affected and fau l ty horny l ayer formati on may ensue . In th i s way,

a c i rcu l u s v i t i osus ma i nta i n i ng or aggravat i ng the barr i er funct i on

d i s turbances, may appear { 78, 97 );

2 ) the functi on of the v i ab l e su bcorneal l ayers of the epidermi s and the

derma l cel l s and structures ( 1 9, 7 8, 79 ) .

The horny l ayer i s the f i na l product of ep iderma l renewa l . The i ntegri ty

of the horny l ayer funct i ons i s therefore determi ned by both the deeper

l ayers of the epidermi s and the subepiderma l structures . The epi derm i s,

hav i ng no i ntri n s i c vascu l ar supply, i s dependent on the derm i s for nu­

tri t i ve and other essent ia l substances . Growth and di fferent iat i on of

epidermal cel l s is a l so partl y regu l ated by the contact of the epi dermi s

w i th subepi derma l structures ( 1 1 1 - 1 13 ) . I nterposed between the body and

the envi ronment, the capac i ty of the epidermi s to form an eff i c i ent bar­

r i er i s a l so i nf l u enced by externa l factors . For exampl e, after penetra­

ti on, a su bstance may damage the v i abl e cel l s of the epi dermis or may

e l i c i t i nfl ammatory responses resu l t i ng i n fau l ty horny l ayer format i on

( 19, 109 ) .

Derma l pathol ogy, e . g . , i nsuff i c i ent neural or vascu l ar supply, (ma i n l y )

epidermal pathol ogy, e . g . , d i sorders o f kerati n i zati on l i ke psori asi s or

i chthyos i form dermatoses, ( endogeneou s ) eczematou s processes and unfa­

vourab l e externa l factors may i nf l uence the epi dermal cel l s and horny

l ayer format i on ( 31, 109, 1 14- 1 1 6 ) .

Most ly, however, the epidermi s, prov i ded wi th a wel l -devel oped enzymat i c

system, can cope wi th changes i n both the externa l and i nternal envi ron­

ments . There i s a bal ance between the demands whi ch are made on the s k i n

and i ts repa i r and thus protecti ve capac i ty ( 1 1 3 ) . The s k i n i s ab l e to

adapt to i ncreased envi ronmental stresses { 109, 1 1 0 ) . The capaci ty of the

sk i n to react to i ncreased envi ronmental demands by adaptati on and rege­

nerati on vari es i nter- and i ntrai nd i v i dua l l y and i s determi ned by i nter­

nal ( cons t i tut iona l ) factors ( age, s k i n type, sk i n reg i on, med i cati on,

neura l and vascu l ar i ntegri ty, s k i n temperature, i nterna l d i sease, fat i ­

gue, etc . ) and externa l factors ( chem i ca l s, i nfrared i rrad i ati on, mecha­

n i ca l forces, rel at i ve hum i d i ty, mi crobes, etc . ) ( 1 9, 7 8, 79 ) .

32

Horny l ayer barr i er funct i on impa i rment and contact dermati t i s

Barr i er funct i on impa i rments may p l ay a rol e i n the eti ol ogy of both

i rri tant and a l l erg i c contact dermati ti s ( 79 ) .

The term i rr i tant contact dermati t i s i s u sed to descr i be a l oca l i zed ,

superf i c i a l , exudative nonimmunol og i ca l i nf l amma t i on of the s k i n wh i ch

i s due to the d i rect i nfl uence of one or more externa l factors ( 78 ) .

Most ly , after repeated contact wi th d i fferent potenti a l i rri tants , the

eczematous reacti on devel ops ( 7 8 ) .

The exact pathogenes i s of i rri tant contact dermat i t i s , however , i s

un known , a l though i t seems l i ke ly that the same mechan i sm a s i n the

pri mary i rri tant react i on of the s k i n wh i c h can be observed after patch

tes t i ng a tox i c substance i s i nvol ved ( 1 1 7 , 1 1 8 ) .

The centra l rol e of permeabi l i ty shou l d be poi nted out : wi thout permea­

t i on , no tox i c effects can be observed ( 79 ) . Therefore , i t i s very

l i kely that i ncreased permeation of ( toxi c ) subs tances contri bute to the

devel opment of i rri tant contact dermati ti s ( 79 ) . Al l erg i c contact derma­

t i t i s i s the term u sed to describe an infl ammatory process of the s kin

based on immunol og i cal mechan i sms . The mechan i sm of del ayed-type hyper­

sens i t i v i ty i s most important i n the devel opment of a l l erg i c contact

derma t i tis . A compl ete descri pti on of t h i s mechani sm i s not wi th i n the

scope of th i s chapter . In s hort : The process of hypersens i t i v i ty deve­

l ops in two phases . F i rs t , the sens i ti zati on process takes p l ace , i n

wh i ch immunocompetent anti gen- i nexperi enced T lymphocytes become commit­

ted by an enconter wi th a conj ugate of l ow mol ecul ar wei ght ( the hapten )

and an autol ogous prote i n .

I n th i s phase , Langerhans cel l s may p l ay a rol e . These cel l s have been

i mp l i cated as antigen-presenti ng and target cel l s i n contact a l l erg i c

( cel l -med i ated ) reacti ons . I n the fol l owi ng el i c i t i ng phas e , a

second contact of the a l l ergen w ith the s k i n may l ead to recogni t i on by

effector T lymphocytes (wh i ch have devel oped as the memory T l ymphocytes

from the comm itted l ymphocytes ) . The effector cel l s wi l l produce lympho­

k i nes wh i ch i nduce i nfl ammatory reacti ons and subsequentl y the devel op­

ment of a l l erg i c contact dermati t i s ( 1 1 9 , 120 ) .

For a l l ergic contact dermatitis , it a l so app lies that it cannot devel op

wi thout permeati on of a l l ergens through the horny l ayer . Both the conduc-

33

t i v e and the el i c i t i ng phase can occur on l y i f an a l l ergen permeates the

horny l ayer ( 7 9 , 12 1 ) .

Kl i gman ( 1966 ) found a strong enhanc i ng effect on sens i t i za t i on i f the

s k i n was pretreated wi th substances wh i ch impa i r the barr ier functi on of

the s k i n , espec i a l l y if the substance a l so evo ked an i nf l ammatory re­

sponse . The i nfl ammat i on was con s i dered to del ay restorat i on of the

barri er i ntegri ty ( 1 22 ) .

Lanti nga et a l . ( 1983 ) demonstrated that pati ents wi th eczematou s pro­

cesses of l onger durati on have more pos i t i ve a l l erg i c patch test reac­

t i ons ( equal exposure i n both groups i s l i ke ly ) than those wi th an

eczema of s horter dura t i on ( 123 ) .

I t may be concl uded that i rr i tant factors may cause barr i er functi on

i mpa i rment and i rr i tant contact dermati t i s , wh i ch may l ead secondari ly

to sens i t i za t i on and a l l erg i c contact derma t i t i s ( "two phases eczema " ) ( 79 ) .

Summar i z i ng , i t can be stated that the i ntegri ty of barr i er functi on i s

essent i a l for the preven t i on of both a l l erg i c and i rr i tant contact der­

mat i t i s ( Fi g . V ) .

34

I rr i tant or Allergic

Contact Dermati tis

Noxae

! Permea b i l i t y

'-------------:;.. Integrity of the Horny Layer

t Const i tuti o n

F i g . V . The i nteract i on between contact dermat i t i s and horny l ayer

permeab i l i ty . Freely adapted from Ummenhofer ( 1981 ) ( 79 ) .

35

��ATER VAPOUR LOSS AS INDICATOR FOR BARR IER FUNCTION !MPAIRI,1£NT

36

Water vapour l os s as i nd i cator for barr i er func t i on i mpai rment

Much work has been done to eval uate the barri er funti on of arti fi c i a l l y

damaged o r d i seased sk i n ( 14 , 29- 3 1 , 1 02-1 08 , 1 1 0 ) .

Among other phys i ca l methods ( carbon d i ox i de mea surements , s k i n i mpeda nce

measurements ) , water vapour l os s methods have been used to s tudy the

barr i er properti es of the s k i n ( 34 , 102 , 1 03 ) .

The method of water vapour l os s meas urements has been used for eva l uat i on

of s k i n barr i er function becaus e :

1 ) the horny l ayer barr i er i s deci s i ve for the penetrat i on o f most chem i ­

cal s i nc l ud i ng water ( 1 , 18 , 69 ) ;

2 ) the horny l ayer behaves l i ke a pass i ve d i ffus i on med i um , obeyi ng

Fi ck ' s l aw to a certa i n extent ( 1 , 18 , 69 ) .

Thi s i mpl i es that penetrat ion of substances i s proporti onal to the di ffe­

rence i n concentra t i on across the s tratum corneum , i ndependent of the

di recti on of the ski n grad i ent ( i . e . , the fl ux of potenti a l l y damagi ng

agents from the envi ronment through the horny l ayer i s essenti a l ly the

same pass i ve mechan i sm as the l os s of water from the body through the

epi dermi s ) ( 1 , 18 , 69 ) .

F i c k ' s l aw , however , assumes that the s tratum corneum i s a homogeneous

d i ffus i on barri er ; t h i s is not stri ctly true because ( 1 ) :

1 ) the appendages ( ha i r fol l i c l es , sweat g l ands ) i nterrupt the horny

l ayer ( 1 ) ;

2 ) the u nbroken stratum corneum cons i sts of an i ntra- and an i ntercel l u­

l ar compartment of d i fferent compos i ti on ( 52 ) . Even the i ntracel l u l ar

compartment cons i st i ng of fi l aments and a n amorphous i nterfi l amentous

matr i x i s not homogeneous .

Consequentl y , each subs tance wi l l have i ts own pattern of d i ffus i on a l ong

the d i fferent pathways ( i ntra- and i ntercel l u l a r , appendages ) accordi ng

to i ts phys i ca l properties (mo l ecu l ar wei ght , e l ectri ca l c harg e , hydro­

ph i l i c of hydrophobi c characteri s t i c s ) ( 1 , 49 , 6 1 ) .

Damage to the s k i n wi l l not equa l ly affect a l l s tructures whi ch are

i mportant for barri e r funct i on ( 1 0 5 ) . Penetrati on of chemi cal s wi l l

therefore not be equa l l y i nfl uenced for a l l subs tances . For exampl e ,

i f the i ntercel l u l ar compartment i s seri ous l y damaged by surface acti ve

37

agents , the i ntracel l u l ar compartment may be rel ati vely i ntac t .

Hence , s k i n water vapour l os s measurements c a n b e cons i dered as g i v i ng

some i nformat i on on the barr i er funct ion of the horny l ayer , espec i a l ly

for substances hav i ng phys i cochem i ca l properti es resembl i ng those of

water .

38

E v a p o r a t i o n

T h e r m i s t o r

C y l i n d r i c a l c a p s u l e

F i g . V I . Arrangement o f sensors i n the probe o f the Servo Med Evapor i ­

meter . From N i l sson ( 1 977 ) ( 140 ) .

39

PERSONAL AND ENV I RONMENTAL VAR IABLES I NFLUENCING SK IN WATER

VAPOUR LOSS

40

Personal and envi ronmental vari abl es i nfl uenc i ng s k i n water vapour l os s

S k i n water vapour l oss varies cons i derab ly wi t h i n a subject a n d between

subj ects ( 34 , 107 ) . D i fferences i n s k i n water vapour l os s as caused by

horny l ayer ( functi on ) i mpai rment are mas ked by the i nfl uence of un­

des i rab l e i nterven i ng vari abl es . Therefore , attempts have been made to

reduce the i nfl uence by keepi ng i nterven i ng var i abl es constant or by

correct i ng sk i n water vapour l oss for the i nfl uence of the i nterven i ng

va r i a b l es ( 34 ) .

I n th i s study , s k i n water vapour l os s measurements were done under neu­

tral envi ronmental cond i t i ons . Before the actua l determi nati on s , a wa i ­

t i ng peri od was a l l owed i n order to reduce the effect of d i fferences

i n eccr i ne sweati ng and s k i n temperature (most i mportant i nterven i ng

var i a b l es ) .

The i nfl uence of i nterven i ng vari a b l es , howeve r , cannot be excl uded

compl etel y . On the one hand , the des i gn of the s tudy prevented compl ete

control of envi romental vari abl es ; on the other hand, restr i ct i on of a l l

i nterveni ng persona l vari abl es i s pract i ca l l y i mposs i b l e ( 34 } . The most

important vari abl es wi l l be d i scussed ( be l ow ) .

S k i n temperature

I n the absence of sweat g l and acti v i ty , s k i n wa ter vapour l oss vari es

wi th the s k i n temperature ( 2 2, 3 2 , 43 , 92 , 1 24- 1 2 7 ) . The rel at i on s h i p be­

tween transep iderma l water l os s and s k i n temperature proved to be ex­

ponent i onal and d i fferent formu l as have been deri ved for converti ng

transepi derma l water l os s a t a random s k i n temperature to a s tandard

reference temperature ( 1 2 5 , 1 26 ) .

The purpose of th i s conversi on i s to permi t a more accurate compari son

of transepi derma l water l os s data between and w i th i n subj ects ( 126 ) .

Under neu tra l env i ronmental cond i t i on s , the s k i n temperature di ffe­

rences are sma l l and a ny i nfl uence cannot be eas i l y detected { 107 ) .

Moreover , s k i n temperature i s dependent on i n ternal and externa l con­

d i ti ons and there is no u sefu l def i n i t i on for in v i vo measurements

( 12 5 , 1 28 ) .

41

For the conversion , i t i s obl i gatory to i n h i b i t swea t g l and acti v i ty ,

since this acti v i ty i s i nfl uenced by both central sudomotor impu l ses

and focal s k i n temperature . This focal infl uence of s k i n temperature

may be d i rect (without neural i nvol vemen t ) and by neural refl exes and

wi l l therefore a l ter the exponentia l rel a tionship between trans epiderma l

water l oss and s k i n temperature ( 1 29 ) .

A d i urna l var i ation which has been described for transepi derma l water

l oss is probab ly a refl ecti on of a diurnal variati on i n s kin tempera­

ture ( 130 ) .

A l inear rel ations h i p between water l os s and s k i n temperature if swea t

g l and activ i ty i s not inhibi ted has been descri bed ( 92 ) . The sweat g l and

acti v i ty i s considered as a part of a periphera l regu l atory system and

the water l oss as being dependent on s k i n temperature ( 92 ) .

Eccrine sweat g l and acti v i ty

S k i n water vapour l os s partly cons i sts of water vapour originat i ng from

the swea t g l ands even under neutra l environmental circumstances ( 66 , 67 ) .

I f , however , the barr i er capac i ty of the s k i n i s studied by means of

water vapour l oss mea surements , swea t g l and acti vity has to be restr i c­

ted as much as poss i b l e ( 22 ) .

I n th i s study , it was not practi ca b l e to i nh i b i t the ( neura l ) impul ses

to the swea t g l ands by use of anti chol i nerg i c compounds . Thus , i n sp i te

of the precaut i ons ( v i de supra ) , s k i n water vapour l oss may be partly

due to therma l but probab ly more important to emotional sweating . Th i s

may b e a source o f i nfra- and i ntersubject variat i on i n the measurement

resu l ts ( 1 07 ) .

Sources of sys tema t i c fau l ts by errors as a resu l t of eccri ne sweat i ng

may be :

1 ) The measurements were performed on the vol ar s i de of the forearm .

Al though sweating is not excessive in this reg i on ( 8 ) , differences i n

sweat g l and dens i ty and activity may vary from the el bow to the wri s t .

Th i e l e & Mal ten ( 1 972 ) have described a rel a t i on between the water l os s

of t h e forearm a n d i t s circumference ( 92 ) . The product of water l os s

and circumference i s considered a s a rel a tively constant val ue within

42

and between i nd i v i dua l s i f no s k i n pathol ogy i s present .

On ly at the wr i s t may th i s product be s l i ght ly h i gher . To demons trate

th i s rel a ti on correcti on for s k i n temperature shou l d be made . The i n­

fl uence of ci rcumference , wi thout correct i on for d i fferences i n tempe­

ra ture , cou l d not be confi rmed wi th the water vapour l oss measurements

a t the forearm , u s i ng the Servo Med Evaporimeter ( grad i ent estimati on )

( 107 ) .

2 ) Abnormal sweat g l and res ponses i n pat i ents wi th acti ve a top i c derma­

ti ti s after st imu l ati on wi th acetyl chol i ne are found ( 13 1 ) . Therefore ,

pati ents w i t h atop i c dermati ti s may have i ncreased sweat g l and act i v i ty

i n case of neura l acti vati on . F i na l l y , i t s hou l d be noted that theore­

t i ca l ly i ncrea sed water vapour l oss after expos ure of the s k i n to i rr i ­

tants may b e due to functi onal damage to the sweat g l ands , l eadi ng to

i ncreased or decrea sed sweat g l and acti v i ty ( 92 ) .

I nj ury to the sweat g l and epi thel i um may l ead to i ncreased d i ffus i onal

water l oss v ia th i s shunt pathway . D i ffus i onal wa ter l oss v ia shunt

pa thways , however , may be cons i dered as part of transepiderma l water

l oss ( 66 ) .

Rel at i ve humi d i ty of the amb i ent a i r

A re l � ti on between the rel ati ve humi di ty o f the amb i ent a i r and d i ffu­

s i ona l water l os s through the s k i n has been men t i oned in both i n v i tro

( 43 , 50 ) and i n v i vo s tud i es ( 30 , 132 , 133 ) , a l though th i s rel at i on i s not

a l ways eas i ly demonstrated in v i vo ( 3 2 , 13 3 , 1 34 ) . If the horny l ayer ( the

mai n barrier aga i n s t d i ffu s i on a l water l oss ) behaves l ike an i deal mem­

brane wi th permeabi l i ty properti es i ndependent of chang i ng amb i ent hu­

m i d i ty , water l os s can be expected to obey Fi ck ' s l aw ( 50 , 7 7 ) . I ndeed ,

some authors have menti oned a l i near rel at i ons h i p between rel at i ve hu­

m i d i ty of the envi ronmental a i r and transepi derma l water l os s ( 7 1 , 135 ) .

I n rea l i ty , however , the horny l ayer does not behave l i ke an i dea l mem­

brane .

1 ) The horny l ayer absorbs and desorbs water from subcornea l l ayers and

from the envi ronment ( 50 , 77 ) . The permeabi l i ty for water proved to be

dependent on the water content of the horny layer ( 50 , 77 , 1 34 , 136 ) .

43

Th i s phenomenon i nterferes wi th the l i near rel ati ons h i p as pred i c ted

by F i ck ' s l aw ; the actual wa ter l os s after adaption of the s k i n to

the l ower or h i gher envi ronmental humi d i ty bei ng , respect i vel y , l ower

and h i gher than wou l d be expected ( 77 ) .

Gri ce et a l . ( 1 972 ) found an i ncrease i n transepi derma l water l oss i n

go i ng from l ow humid i ty to 30 - 50\ and than a decrea se i f the hum i ­

d i ty i ncreased sti l l more . By 73 - 7 7 � , the transepi dermal water l oss

had decreased to abou t the i n i t i a l rate ( 1 33 ) .

2 ) The water content of the horny l ayer i s dependent not on ly on the en­

v i ronmental humi d i ty but a l so on the way i n wh i ch thi s humi d i ty has

been reached . The water i sotherm from l ow to h i g h humi d i ty i s not

equal to the desorption i sotherm from h i gh to l ow humi d i ty . Thus ,

the water content of the horny l ayer at a fi xed humi d i ty wi l l vary

between the two val ues ( 7 7 ) .

3 ) The gradi ent of rel a t i ve h um id i ty throug h the membrane cannot be d i ­

rect ly establ i s hed , a l though the subcornea l l ayers can probab ly be

cons i dered as ful l y hydrated ( R . H . 100% ) ( 22 , 1 24 ) .

I n th i s s tudy , the rel at i ve hum i d i ty of the ambi ent a i r probab ly d i d not

s i gn i fi cant ly i nfl uence the s k i n water vapour l oss measurements ( 107 ) .

The i nfl uence of a i r movement on eva pora t ion i s probab ly due to con­

stantly l ower i ng the rel at i ve humi d i ty , wh i ch faci l i tates evaporati on

( 124 ) .

Tempera ture of the amb i ent a i r

The temperature o f the ambi ent a i r i nfl uences s k i n temperature both d i ­

rectl y and i nd i rectl y ( by central thermoregu l atory effects ) ( 2 2 , 32 , 1 24 ,

1 28 ) . The temperature of amb i ent a i r wi l l a l so have effects on body tem­

perature . Therefore , sweat g l and acti v i ty wi l l be i nfl uenced by d i ffe­

rences i n temperature ( thermal swea t i ng ) a nd must be cons i dered as an

i mportant var iab l e ( 85 ) .

I f a i r tempera ture i s bel ow 20° C and s k i n temperature bel ow 3 3°C , h ow­

ever , thermal sweat g l and acti v i ty i s un l i ke l y , prov ided that the s k i n

i s not exposed t o forced convecti on and n o exces s i v e body heat i s pro­

duced ( bodi l y excerc i se ) ( 22 , 1 37 ) .

44

I naccurac i es and d i sturbances due to the measuri ng dev i ce

The methods emp l oyed to mea sure s k i n water vapour l os s wi l l more or l ess

a l ter the m i crocl i ma te at the s i te of measuremen t and wi l l therefore

d i s turb the mi croc l imate onl y modera te l y , because of the l i m i ted s i ze

of the measuri ng probe and the absence of a chamber .

The i naccuracy of the measur ing dev i ce ( s ervo Med Evaporimeter ) i s usu­

a l l y i ns i gn i fi cant in compari son wi th factors wh i ch i nfl uence the d i ffu­

s i on zone ( boundary l ayer ) around the body such as a i r movement or fac­

tors wh i ch i nfl uence the sensor el ements and , consequentl y , the gra­

d i ent estima t i on such as , e . g . , d i rect l i gh t or heat sources { 138 ) .

Factors i nfl uenci ng horny l ayer barri er properti es

The propert ies of the horny l ayer are determi ned by const i tut i ona l and

envi ronmental factors ( 19 , 34 , 78 ) . If cons ti tuti onal factors are stud i ed

(wh i c h are on ly part ly hered i tary and cannot be cons i dered as f i xed du­

ri ng the l i fet ime ( 78 ) ) , d i fferences in s k i n water vapour l oss based on

nonstandard i zed envi ronmental factors are i n terven i ng var i a b l e s ( 34 ) .

Therefore , s k i n water vapour l os s measurements i n unexposed s k i n or s k i n

exposed to a s tandard i zed st imu l us g i ve on ly an i mpres s i on of the ( con­

st i tut i ona l l y determ i ned ) vu l nerab i l i ty of an i nd i v i dua l if random i n­

j ur i es to the s k i n are avoi ded . Al so , reg i onal d i fferences i n s k i n pro­

perti es may be of i mportance ( 22 , 124 ) . The vo l a r s i de of the forearm

was used for the exposures and s k i n water vapour l os s measurements i n

th i s s tudy , s i nce t h i s s k i n s i te i s not norma l l y exces s i ve ly exposed to

envi ronmental s t imu l i .

Vascu l ar changes , deep s k i n and body temperature

The i nf l uence of vasoconstr i ct ion and vasod i l atat i on has been suggested

{ 127 ) , but i s probab ly not of importance ( 22 , 124) . Consequent ly deep

s k i n and body temperature wi l l probably have no d i rect i nf l uence on

transep i derma l water l os s .

45

r·lETHODS OF MEASURING THE EVAPORATIVE WATER LOSS OF HUMAN SKIN

46

Methods of measuri ng the evaporati ve water l os s of human s k i n

The f i rst attempts to eva l uate the wa ter l os s from human s k i n were made

i n the 1 7th and 1 8th centuri es and were whol e body grav i metr i c stud i es

( 1 39- 14 0) . The water l oss of the s k i n was estimated by determi n i ng the

wei ght r �ducti on of a person on a wei g h i ng sca l e . After Lavo i s i er and

Segu i n i n 1 7 90 poi nted out the importance of pu l monary l osses of water

and carbon d i ox i d e , correct i on for these l osses was made ( 65 ) .

I n th i s century , i nv est i gati ons wi th improved and more sensi t i ve vers i ons

of these gravimetr i c methods were made to study total cutaneou s water

l oss under phys i o l og i ca l and patho l og i ca l cond i t i ons { 65 , 7 1 , 1 32 , 1 4 1 - 143 ) .

I nves ti gat ion of l im i ted areas of s k i n , however , i s not pos s i b l e i n

th i s way and , to perm i t stud i es of cutaneous water l os s from l i m i ted

areas , new methods have been devel oped . These techni ques are often i n­

tended to assess swea t g l and act i v i ty , e . g . , i n phys i o l og i ca l and psycho­

l og i ca l stud i es . However , they l ack the accuracy to reg i s ter sma l l d i ffe­

rences i n i nsens i b l e water l os s through the epi derm i s ( 144 , 145 ) .

I f we restr i ct our su rvey to method s s u i tabl e for accurate measurement

of water vapour l oss , these i nvol ve the use of : a ) a vent i l ated chamber ;

b ) an unvent i l ated chamber ; or c ) grad i ent estimati on ( 140 ) .

I ) Methods based o n unventi l ated chambers

In the methods based on an unvent i l ated chamber , the water l oss of the

s k i n i s determi ned grav imetr i ca l l y . A chamber wi th i ts open end to the

s k i n surface is fastened to the s ki n . A hygroscopi c mater ia l (most ly

saturated so l ut i ons of s a l t s s uch as NaCl , L i C l , MgC l 2 and NaBr ) p l aced

i ns i de the chamber takes u p the water l ost by the s k i n . The change i n

we i ght o f the hygroscopi c mater i a l i s a measure for the water l os s of

the s k i n per u n i t t ime and s k i n surface { 1 5 , 29 ) .

Al ternat i vel y , the water vapour l os s can be est imated by a hum i d i ty

sensi ng e l ement p l a ced i ns i de the chamber . The sens i ng el ement

reg i sters the rel at ive hum id i ty and the rate of change i n the hum i d i ty

corres pond s to the rate of water vapou r l os s ( 27 , 146 - 148 ) .

I I) Methods based on vent i l ated chambers

In methods based on a vent i l ated chamber , a carr i er gas wi th a known

water content and at a known gas fl ow i s passed through a chamber p l aced

47

with i t s open end on the s k i n . The water l oss of the tested s k i n area i s

proporti ona l to the gas f l ow and the i ncrease i n the water vapour l oss

of the water vapour pres sure of the carr i er gas . I n formu l a format :

water vapour l oss � ( Pout -- P i n ) x f l ow .

The water vapour l oss can thus b e ca l cu l ated ( 140 ) .

The water content of the carr i er gas can be anal yzed grav imetr i ca l l y or

el ectrohygrometri ca l l y . Other methods l es s frequently used are based on

determi nat i on of changes i n therma l conducti v i ty , i nfrared absorpt i on or

temperature d i fferences caused by evaporat i on .

Grav imetri c estimati on of the water content i s done by wei gh i ng the

amount of water removed from the carr i er gas by an absorbent materi a l or

by col l ecti ng the water in a freez i ng m i xture ( 68 , 1 4g- 1 51 ) .

E l ectrohygrometr i ca l ana l ys i s makes use of an absorbent materi a l ( P2o5 )

that takes up the water vapou r of the carr i er gas . The water i s then

sp l i t by exposu re to an e l ectr i c potent i a l d i fference . The e l ectr ic

current resu l t i ng from th i s el ectro lys i s i s a measure for the water l oss

( 26 , 106 , 1 2 5 ) .

Other electrohygrometr i c methods make use of sens i n g e l ements w i th

hygroscop i c fi l ms of whi ch the el ectri ca l conducti v i ty i s i n proporti on

w ith the humi d i ty of the gas passed over i t ( 2 2 , 1 52- 1 54 ) .

The method of thermal conducti v i ty i s based upon the d i fferent therma l

conducti v i ty of gases . The therma l conduct i v i ty cel l detects the d i ffe­

rences in therma l conducti v i ty i f the water content of a gas changes

( 145 , 1 55 , 1 56 ) .

I nfrared gas ana lys i s used as the operati ng pri nc i pl e the absorpti on of

i nfrared radi at i on by water vapour ( 30 , 1 57 ) .

The venti l ated chamber method u s i ng temperature d i fferences to detect

the water vapour pressure i s based upon the phys i ca l l aw that evapora­

t i on i s proporti ona l to the rel ati ve humi d i ty of the ambi ent gas .

Because evaporat i on wi thdraws energy , temperature d i fferences are a

measure for the water content of the carr i er gas ( 1 58 ) .

I I I Determi nat i on of water vapour l os s through s k i n by grad i ent estima­

t i on

Grad i ent estimation i s based on a method devel oped by N i l s son an Oberg

( 1 59 ) .

48

Th i s method depends upon determ i n i ng the vapour pressure g rad i ent i n the

l ayer adjacent to the s k i n . Th i s g radi ent can be con s i dered as propor­

ti ona l to the exchange of water vapour from the s k i n .

The evapora t ion from a fl at and exten s i ve surface can b e treated a s a

f l ux normal to the s k i n wh i ch i s the resu l tant component of random

movement of mol ecu l es . Th i s f l ux through a s tat i onary water permeab l e

l ayer can be expres sed a s :

water exchange

D the mo l ecu l ar d i ffus i on

coeff i c i ent of water vapour

in a i r .

p the vapour pres sure .

x = the d i s tance to the s k i n

surface .

The quant i ty of water evaporated per u n i t t i me and s k i n area can thus

be cal cu l ated accord i ng to :

D llp llx

t t i me .

A area of surface .

m wei ght of the transported

water .

T h i s re l at i on i s va l i d wi t h i n a boundary l ayer ( d i ffu s i on zone ) wh i ch

surrou nds the human body . The depth of th i s stati onary l ayer depends on

the envi ronmental c i rcumstances , but , under neutra l cond i t i ons , t h i s

l ayer wi l l have a depth o f 7 mm t o 1 0 mm ( 1 40 , 1 60 , 1 6 1 ) .

The evaporimeter as desi gned by N i l sson ( 1977 ) , a pa i r of transducers

p l aced in a probe , measu res the rel ati ve humi di ty at two di fferent

d i stances from the surface ; another pa i r reg i sters the temperature and ,

from these s i gnal s , the pressure gradi ent i s computed ( F i g V I , p 39 ) ( 140 ) .

Compari son of the three methods for measurement of evaporat i on

Al l methods for measurement of water evaporat i on more or l es s suffer from

the d i sadvantage that they i nterfere wi th the mi crocl i mate near the

surface of the s k i n . Because th i s i nterference is d i fferent for the

methods appl i ed , resu l ts cannot be compared with any degree of accuracy .

Moreover , t h i s i nterference ma kes i t d i ff i cu l t t o estimate the "true

49

water l os s '' i n the absence of the i nterfer i ng chamber or probe on the

s k i n ( 29 , 1 40 ) .

Unvent i l ated chambers have t he d i sadvantage that the rel at ive hum i d i ty

and temperature i n the chamber cannot be kept constant , a l though some

i nvest i gators deal w i th t h i s probl ems i ngen ious ly ( 27 , 148 ) .

I f a grav imet r i c method i s u sed , the hyg roscopi c mater i a l wi l l a l so take

up the water va pou r a l ready present in the chamber ; therefore , a bl ank

determi nat i on has to be carr i ed out ( 1 62 ) .

Another probl em concern i ng t he grav imetr i c unventi l ated method i s the

impos s i b i l i ty of ma ki ng trans i ent record i ng s ( 1 40 ) .

The vent i l ated chamber methods make use of forced convect ion by pass i ng

the carri er gas throug h the chamber ; cons equent ly , extrapol at ion to a

zero f l ow or more accuratel y to a fl ow correspond i ng wi th the f l ow

immed i ately above the body su rface of a person under neutral ambi ent

c i rcumstances i s requ i red { 3 0 , 1 54 , 1 55 ) . However , the gas f l ow can s t i l l

i nf l u ence the hydrat i on and temperatu re of the s k i n ( 1 44 , 1 54 ) .

To obta i n comparab l e resu l ts corres pond i ng wi th the " true water vapour

l oss " , amb i ent a i r shou l d be u sed ; howev er , the u s e of a i r makes great

demands on the sens i t i v i ty of the mea su rement ( 140 ) . In fact , most

met hod s make use of dr i ed n i trogen or oxygen at d i fferent gas f l ows .

When u s i ng a vent i l ated chamber , the measurement i s often quan l i ta t i ve

and ta kes much t ime because of the dead s pace i n t he c i rcu l at i ng system .

Mechan i cal i nf l uence of the chamber can cause a change i n s k i n vapour

l os s . The chamber must be pressed on to the s k i n to avo i d m i x i ng of

amb i ent a i r w i th the gas in the system or to avo i d l ea kage of carri er

gas ( 3 1 , 92 ) .

The method of grad i ent est imat i on i s wi thout many of the d i sadvantages

of the c hamber methods and , becau se of i t s s impl i c i ty , it i s easy to

hand l e in da i l y pract i ce ( 1 63 ) . The i nterference of the measu r i ng probe

w i th the m i crocl imate of the s k i n i s l im i ted to s i tuati ons w i th rap i d

evaporat ion .

The mechan i cal i nfl uence of the probe on the s k i n i s smal l .

The resi stance to d i ffus i on of water vapour i n the cyl i ndri cal probe

may be greater than the boundary l ayer surround i ng the s k i n i n cases of

rap i d evaporat i on . In these s i tuat i ons , g radi ent est i mati on underva l ues

50

the actual evaporati on . A correct i on for th i s phenomenon can be made

( 16 1 , 164 ) .

The theoreti cal sens i t i v i ty defi ned as the grad i ent of the s i gnal output

of the measuri ng i ns trument and the water exchange of the method of

grad i ent est imati on i s super i or to the sens i t i v i ty of the chamber

methods ( 1 65 ) . The actual accuracy of the grad i en t est imati on methods i s

d i scus sed i n the next sect i on .

Servo Med evapori meter(138 )

The Servo Med evapori meter used i n th i s s tudy i s an i nstrument for

quant i ta t i ve determi nation of evaporati ve water l os s . Its opera t i ng

pri nci p l e i s based on the method of gradi ent es t i mati on as devel oped

by N i l sson and Oberg ( 140 ) .

The actual i nstrument cons i sts of a detac habl e hand- hel d probe attached

by a cabl e to a portabl e control un i t .

The sensor arrangement of the probe i s p l aced i n a tefl on caps u l e wh i ch

i s shaped as an open cyl i nder and measures 1 5 . 5 mm i n l ength and 1 2 . 5 mm

i n wi dth .

By p l a c i ng th i s cyl i nder upon the s k i n , a sma l l area i s separated and

protected from d i s turb i n g draughts . At two po i n ts a l ong an a x i s

perpend i cu l ar t o the measuri ng s urface , both humi d i ty transducers

and thermi stors are s i tuated i n the cyl i nder . The s i gna l s of the

transducers for rel ati ve humi d i ty and those of the thermi s tors are

used to compute the part i a l pressure of the water vapour and the

temperature at two d i s tances 4 mm apart from the measuri ng surface .

The pa rt ia l pressure grad i ent and evaporat i on rate can thus be cal cu­

l a ted .

The el ectron i c control and d i s p l ay u n i t offers the fol l owi ng measuri ng

poss i b i l i t i es and ranges . If only the "WE" swi tch i s pres sed , the

range for water eva porat i on or water uptake from or to surfaces i s

0 - 300 g/m2h . When a l s o pres s i ng the swi tch " Range " , the d i s p l ay

covers the 0 - 1 00 . 0 range . Moi s ture measurements by both pai rs of

transducers can be done by pres s i ng the swi tches RH or P for rel at i ve

humi d i ty or parti a l water vapour pres su re , respec t i ve l y . Rel a t i ve

51

humi d i ty can be determi ned wi th i n the range of 0 - 100, and part i a l

wa ter vapour press ure wi th i n the range o f 0 - 6 . 65 KPa ( 0 - 5 0 mm Hg ) .

Mea surement pri nc i p l es and accurac i es of the Servo Med evaporimeter(138)_

The d i s turba nce , defi ned as the d i fference between the water evaporation

duri ng the meas urement and what the evaporat i on wou l d have been wi thout

appl i cat i on of the mea suri ng dev i ce , is norma l l y many t i mes grea ter than

the i naccuracy of the eva porimeter .

Th i s means that a l l effects such as draughts , d i rect l i ght , etc . ,

d i s turb i ng the mi crocl imate and thus the boundary l ayer of the s k i n

shou l d be mi n imi zed . For accura te measurements , care must be taken to

do a correct ca l i brati on . Cal i brati ons at a 3-month i n terva l i s usua l ly

sat i s fac tory . Before the actua l measurement , a 15 m i n warm up t i me for

the i nstrument i s advi sabl e .

When the warm u p t ime has el apsed , the i n s trument h a s to b e zeroed wi th

the " offset" potenti ometer . To el i minate edge effects cau s i ng a d i s tur­

bance of the " s tat i onary" boundary l ayer , the probe shou l d be p l aced on

as l arge a s k i n surface as poss i b l e .

After p l a c i ng the probe properly on the s k i n , the response t i me for

measurement of evaporati ve water l oss i s very short . However , for very

stati onary va l ues , a m i n ima l t ime dura t i o n of three mi nutes i s requi red

( 1 66 ) . Fi l ter buttons ( 10 and 20 s ) can be used separately a nd s i mul taneou sly

to avo i d fa st fl uc tua ti ons in the d i s p l ayed va l ues . The ul t imate va l ue

of the eva pora t i ve wa ter l os s , however , i s atta i ned more s l owly by the

use of the f i l ters .

The actual accuraci es depend on the t ime that the sensor un i t i s a l l owed

to reach the amb i ent temperature . Tha t i s 1-1hy i t i s neces sary to avo i d

heat transfer t o the probe by suns h i ne , t h e hand or otherwi s e . Even so ,

i f moi sture cond i t i ons change abrupt l y , i t wi l l take some t i me before

a d i ffu s i on equ i l i br i um i n the measur i ng probe i s atta i ned .

After ca l i bra ti on and at l east 5 mi n appl i cat ion of the probe , the

typ i ca l accuraci es are (wi thi n the temperature range of 18 - 3 5° C ) :

52

Water transport ;

Rel ati ve hum id i ty ;

Part i a l pressure ;

+ + 2 1 5% - 2 g/m h . : 2%-un i ts wi th i n the range 0-65% ,

+ 3%-uni ts wi th i n 65-80� .

! 6% wi th i n 20- 100% rel at i ve hum i d i ty .

53

References

1 ) Scheup l e i n , R . J . Percutaneous absorpt i on after twenty-five years :

or o l d w ine i n new wi nes ki ns . J . I nves t . Derm . 6 7 : 31 -38 ( 1 976 ) .

2 ) Rothman , S . Percutaneous absorpt i on . I n : Phys i ol ogy and B i ochemi stry

of the Sk i n , pp 27-29 ( 1 954 ) The Un i vers i ty of Ch i cago Press ,

Ch i cago .

3 ) Schwen kenbecher , A . Das Absorpt ions vermogen der Hau t . Arch . Anat . u .

P hys i o l . 1 2 1 - 165 ( 1 904 ) .

4 ) B l a n k , I . H . Cutaneous barr i e rs . J . I nves t . Derm . 45 : 249-256 ( 1965 ) .

5 ) Rei n , H . Exper imental el ectroendosmot i c stud i es on l i v i ng huma n

s k i n . Z . B i ol . 81 : 125- 140 ( 1 924 ) .

6 ) Mackee , G . M . , Su l zberger , M . B . , Herrma nn , F . , Baer , R . L . H i sto l og i c

stud i es o n percutaneous penetrat i on w i t h spec i a l reference to the

effects of veh i c l es . J . I nves t . Derm . 6 : 43-6 1 ( 194 5 ) .

7 ) Wi nsor , T . , Burch , G . E . Di fferen t i a l ro l es of l ayers of human ep i ­

gastri c s k i n on di ffu s i on of water . Arch . I ntern . Med . 7 4 : 428-444

( 1 944 ) 0

8 ) Rothman , S . I nsens i b l e water l oss . I n : Phys io l ogy and Bi ochem i stry

of the S k i n , pp 1 53-200 and pp 233-243 ( 1 954 ) The Un i vers i ty of

Ch i cago Pres s , Ch i cago .

9 ) Mal i , J . W . H . The transport of water through the human epi dermi s .

J . I nvest . Derm . 27 : 451 -469 ( 1956 ) .

1 0 ) Wol f , J . D i e i nnere Struktur der Zel l es des Stratum Desquamans der

mensch l i chen Epi dermi s . Z . Mi k ros k . Ana t . Fors ch 46 : 1 70-202 ( 1939 ) .

1 1 ) P i nkus , H . Exami nati on of the epi derm i s by the str i p method of

remov i ng horny l ayers . J . Inves t . Derm . 1 6 : 383-386 ( 19 5 1 ) .

1 2 ) B l a n k , I . H . Factors w '• i�h i nfl uence the water content of the stra tum

corneu� . J . I nvest . Derm . 18 : 433-440 ( 1952 ) .

1 3 ) Bl a n k , I . H . Further observa ti ons on factors wh i c h i nfl uence the

water content of the stratum corneum . J . I nvest . Derm . 2 1 : 259-269

( 1 953 ) .

1 4 } Spru i t , D . The measurement and the regenerat i on of the water vapour

l os s of human s k i n . pp 58-59 ( 1969 ) Thes i s ( N i jmegen ) Offsetdrukker i j

mi nOpri nt , N i jmegen .

54

1 5 ) Monas h , S . , B l an k , H . Locat i on and re-formation of the epi thel i a l

ba rri er t o water va por . Arch . Derm . 7 8 : 7 10-7 13 ( 1958 ) .

1 6 ) B l a n k , I . H . , Scheupl e i n , R . J . Transport i nto and wi th i n the sk i n .

B r . J . Derm . 81 , suppl ement 4 : 4- 10 ( 1969 ) .

1 7 ) Schaefer , H . , Zesch , A . and Stuttgen , G . S k i n permeabi l i ty . I n :

Handbuch der Haut und Geschl echtskrankhei ten . Norma l e und Pathol og i ­

sche Phys i ol og i e der Haut I I I , J . Jadassohn , p p 575-577 ( 1981 )

Spri nger Verl ag , Berl i n .

1 8 ) Dugard , P . H . S k i n permeabi l i ty theory i n rel ati on to measu rements

of percutaneou s absorption in tox i col ogy . I n : Dermatotox i col ogy and

Pharmacol ogy , pp 525-550 ( 1 977 ) Edi tors : F . H . Marzu l l i and H . I .

Ma i bach , Hem i s phere Publ i s h i ng Corpora t i on , Wash i ng ton .

1 9 ) Mal ten , K . E . Dermato l og i sche tox i c i te i tsmeti ng . Lecture del i vered

at the sympos i um ' arbe ids- en bedri j fsgeneeskunde ' ( 1980 ) E i ndhoven .

20 ) W inke lmann , R . K . The rel a t i onshi p of the structure of the epi dermi s

to percutaneou s absorpti on . Br . J . Derm . 81 : suppl ement 4 , 1 1 - 2 1

( 1969 ) .

2 1 ) Kl aschka , F . Veranderungen der Hornsch icht bei Feucht i g kei tss chwan­

kungen i n v i vo . Fette , Sei fen und Anstri chmi ttel 84 : 204-207 ( 1 982 ) .

2 2 ) Baker , H . , Kl i gman , A . M . Measurement of transepiderma l water l os s by

el ectri cal hygrometry . Arc h . Derm . 96 : 441-452 ( 1967 ) .

2 3 ) Menczel , E . , Ma i bach , H . I . I n v i tro human percutaneous penetrat i on

of benzyl a l cohol and testosterone : epi dermal -dermal retenti on . J .

I nves t . Derm . 54 : 386-394 ( 1970 ) .

2 4 ) Fel dman , R . J . , Ma i bach , H . I . Penetrati on of hydrocort i s one through

normal s k i n . Arch Derm . 9 1 : 661-666 ( 1965 ) .

2 5 ) Sprui t , D . , Mal ten , K . E . Epi dermal water- barri er formati on after

stri ppi ng of norma l s k i n . J . I nves t . Derm . 4 5 : 6 - 14 ( 1965 ) .

26 ) Van Gassel t , H . R . M . , V i erhout , R . R . Reg i stra t i on of the i nsens i b l e

pers p i ra t i on o f sma l l quanti t i es o f sweat . Dermato l og i ca 1 2 7 :

255-259 ( 1963 ) .

27 ) Ohara , 0 . , Ono , T . Reg i ona l rel ati onsh i p of water vapour pressure of

human body surface . J . Appl . P hys i ol . 18 ( 5) : 10 19- 1022 ( 1963 ) .

28 ) Thi el e , F . A . J . , van Senden , K . G . Rel a t i onsh i p between s k i n tempera­

ture and the i nsen s i b l e persp i ra t i on of the human s k i n . J . I nvest . Derm .

55

4 7 ( 4 ) : 307 -3 1 2 ( 1 966 ) .

29 ) Shah i du l l ah , M . , Raffl e , E . J . , Fra i n-Bel l , W . I nsens i b l e water l oss

in dermati ti s . Br . J . Derm . 79 : 589-597 ( 1 967 ) .

3 0 ) Johnson , C . , Shuste r , S . The measu rement of transepi dermal water

l oss . Br . J . Derm . 81 ( suppl . 4 ) : 40- 45 ( 1 969 ) .

3 1 ) Shah i du l l ah , M . , Raffl e , E . J . , R immer , A . R . , Fra i n-Bel l , W . Trans­

epi dermal water l oss in pati ents wi th dermati ti s . Br . J . Derm . 81:

722-730 ( 1969 ) .

32 ) Lamke , L . O . , Wedi n , B . Water evaporati on from norma l s k i n under

d i fferent envi ronmental cond i t i ons . Acta Derm . Vener . 5 1 : 1 1 1- 1 1 9

( 1 97 1 ) .

33 ) Lamke , L . O . , N i l sson , G . E . , Rei thner , H . L . I nsens i b l e perspi rat i on

from the s k i n under norma l envi ronmental condi ti ons . Quotat i on i n :

Measurement of water exchange through s ki n . N i l s son , G . E . , Med . &

B io l . Eng . & Comput . 1 5 : 209- 2 18 ( 1977 ) .

3 4 ) de Jongh , G . J . Poros i ty of human s k i n i n vi vo assessed v i a water l oss ,

carbon d i ox i de l oss and el ectri cal i mpedance for heal thy vol unteers ,

atop i c and psori ati c pa t i ents . Ed i tor : J . W . H . Mal i . Curr . Prob l .

Derm . , vol . 9 : 83- 101 ( Karger , Basel ) ( 1981 ) .

3 5 ) Baker , H . The s k i n as a barri er . I n : Textbook of Dermatol ogy , pp

289-298 ( 1979 ) Edi tors : A. Rook , D . S . Wi l k i nson , F . J . G . Ebl i ng .

Bl ackwe l l Sc ient i f i c Publ i cati ons part I , Oxford .

36 ) Matol tsy , A . G . , Downes , A . M . , Sweeney , T . M . Stud i es of the epi dermal

water l oss water barr ier , part I I . I nvesti gati on of the chemi ca l

nature of the water barri er . J . I nvest . Derm . 50 : 19-26 ( 1968 ) .

37 ) V i ckers , C . F . H . Kerati n and wate r . Br . J . Derm . 80 : 469-471 ( 1968 ) .

38 ) Smeen k , G . De i nv l oed van detergenti a op de hui d . Thes i s J .

Noorduyn en Zoon N . V . Gori nchem pp 4 1 -45 ( 1968 ) .

39 ) Gri ce , K . A . Transepi derma l water l oss . I n : The Physi ol ogy and Patho­

phys i o l ogy of the Ski n , Vol . 6 , pp 2 134-2 142 ( 1 980 ) Ed i tor : A .

Jarret . Academi c Press , London .

40 ) Tregear , R . T . The structures wh i c h l i m i t the penetrabi l i ty of the

sk i n . J . Soc . Cosmet . Chern . 1 3 : 145- 1 5 1 ( 1962 ) .

4 1 ) Ja rret , A . The permeab i l i ty barri er . I n : The Phys i o l ogy and Patho­

phys i o l ogy of the Ski n , vol . 6 , pp 2 1 1 1 - 2 1 14 ( 1980 ) Ed i tor : A .

56

Ja rret . Academ i c Press , London .

42 ) Sweeney , T . M . , Down i ng , D . T . The rol e of l i p i ds i n the epi derma l

barr i er to water . J . I nvest . Derm . 5 5 : 1 3 5 - 1 39 { 1970 ) .

43 ) Berenson , G . S . , Burch , G . E . Stud i es of d i ffus i on of water through

dead human s k i n : The effect of d i fferent envi ronmental s tates and

of chemi cal al tera t i ons of the epi derm i s . Amer . J . Trop . Med . 3 1 :

842-853 ( 1 951 ) .

44 ) Onken , H . D . , Moyer , C . A . The water barri er i n human epi dermi s . Arch .

Derm . 87 : 584- 590 ( 1 963 ) .

45 ) Scheu pl ei n , R . J . , B l ank , I . H . Permeab i l i ty of the s k i n . P hys i o l .

Rev . 5 1 : 702-747 ( 19 7 1 ) .

46 ) E l i as , P . M . , Cooper , E . R . , Korc , A . , Brown , B . E . Percutaneous

transport i n rel at i on to stratum corneum s tructure and l i p i d compo­

s i t i on . J . I nvest . Derm . 7 6 : 297-301 { 1 981 ) .

47 ) Tregea r , R . T . The permeabi l i ty of mamma l i an s k i n to i ons . J . I nves t .

Derm . 46 : 16-23 ( 1966 ) .

48 ) Baker , H . Factors i nfl uenc i ng barri er i ntegr i ty . I n : Textbook of

Derma to l ogy , pp 294-295 { 1 979 ) Edi tors : A . Roo k , D . S . W i l k i nson ,

F . J . G . Eb l i ng . B l ackwe l l Sc ient i fi c Pub l i cati ons Oxford part I ,

Oxford .

49 ) Scheupl ei n , R . J . Mechan i sm of percutaneous adsorpti on I . Routes of

penetrat i on and the i nfl uence of sol ub i l i ty . J . I nves t . Derm . 45 :

3 34-345 ( 1 965 ) .

50 ) Spru i t , D . , Mal ten , K . E . Humi d i ty of the a i r and water vapour l oss

of the s k i n . The chang i ng permea bi l i ty . Derma tol ogi ca 138 : 418-426

( 1969 ) .

51 ) Smi th , W . P . , Chr i s tensen , M . S . , Nacht , S . , Gans , E . H . Effect of

l i p i ds on the aggregat i on and permeab i l i ty of human s tra tum corneum .

J . I nves t . Derm . 7 8 : 7 - 1 1 { 1982 ) .

52 ) E l i as , P . M . , Grayson , S . , Lampe , M . A . , W i l l i ams , M . L . , Brown , B . E .

The i ntercorneocyte space . I n : Stratum Corneum , pp 53-67 { 1983 )

Ed i tor : R . Marks . G . P l ewi g Spri nger Verl ag , Berl i n .

53 ) Prottey , C . , Hartop , P . J . , Press , M . Correcti on of the cutaneous

man i festa t i on of essent i a l fatty ac i d defi c i ency i n man by appl i ca­

t i on of sunfl ower seed oi l to the s k i n . J . I nves t . Derm . 64 :

57

228-234 { 197 5 ) .

54 ) Prottey , C . , Hartop , P . J . , B l ack , J . G . , McCormack , J . I . The repa i r

o f i mpai red ep i dermal barri er funct i on i n rats by the cutaneous

appl i cat ion of l i no l e i c ac i d . Br. J . Derm . 94: 13-21 ( 1976 ) .

5 5 ) Hartop , P . J . , Prottey , C . Changes i n transepi derma l water l oss and

the compos i t i on of epi derma l l ec i th i n after appl i cati ons of pure

fatty acid tri g lyceri des to the s k i n of essenti a l fa tty aci d­

def i c i ent rats . Br . J . Oerm . 95 : 255- 264 { 1976 ) .

56 ) Prottey , C . I nvesti ga t ion of functi on s of essenti a l fatty ac ids i n

the ski n . Br . J . Derm . 97: 29-38 { 1977 ) .

57 ) Houtsmu l l er , U . M . T . , v . d . Bec k , A . Effects of top i cal appl i ca-

t i on of fatty ac ids . I n : Prog . L i p i d Res . pp 2 19-224 ( 1981 )

Ed i tor : R . T . Ho lman . Perganon Press .

58 ) E l i as , P . M . , Brown , B . E . , Fri tsch , P . , Goerke , J . , Gray , G . M . ,

Wh i te , R . J . Loca l i zati on and compos i t i on of l i p ids i n neonatal mouse

stratum granul osum and stratum corneum . J . I nves t . Derm . 73 :

339- 348 ( 19 79 ) .

5 9 ) E l i as , P . M . , Goerke , J . , Fri end , D . S . Mamma l i an epi derma l barr i er

l ayer l i pi d s : compos i t i on and i nfl uence on structure . J . I nves t .

Derm . 69 : 535- 546 ( 1977 ) .

60 ) Gr�yson , S . , E l i a s , P . M . I so l ati on and l i p i d b i ochem ica l characteri za­

t i on of stratum corneum membrane comp l exes : Impl i cati ons for the

cutaneous permea bi l i ty barr ier . J . Inves t . Derm . 78: 128- 135 ( 1982 ) .

6 1 ) Nemani c , M . K . , E l i as , P . M . I n s i tu prec i p i tat ion i n novel cyto­

chem i ca l techni que for v i sual i zati on of permeabi l i ty pathways i n

mamma l i an stra tum corneum . J . H i stochem . Cytochem . 28 : 573-578

( 1 980 ) . 62 ) Jarret , A . Norma l ep iderma l kerat i n i zat i on . I n : The Phys i o l ogy and

Pathophys io l ogy of the Sk i n , Vol . 1 , p . 198 ( 1 973 ) Ed i tor : A. Jarret . Academ i c Press , London .

63 ) Mackenz i e , I . C . The cel l u l ar archi tecture of the stratum corneum . I � : Stratum Corneum , pp 146- 152 { 1 983 ) Edi tors : R . Marks , G . P l ewi g , Spri nger Verl ag , Berl i n .

64 ) Yard l ey , H . J . I so l ati on and l i p i d compos i t i on of fracti ons from the superf i c i a l stra tum corneum of the p i g . I n : Stratum Corneum , pp 73-78

58

( 1983 ) Edi tors � R . Marks ,G . P l ewi g , Spri nger Verl ag , Berl i n .

6 5 ) Bened i c t , F . G . , Root , H . F . I nsens i b l e pers p i rati on : i ts rel at i on to

human phys i o l ogy and pathophy s i o l ogy . Arch . I n t . Med . 38 : 1 -35

( 1926 ) .

66 ) Thi el e , F . A . J . The water l os s by s k i n . I n : Handbuch der Haut und

Geschl echtskrankhei ten , pp 5-8 ( 1981 ) Ed i to r : J . Jadas sohn . Norma l e

u nd Pathol og i sche Phys i o l og i e der Haut I I . Spri nger Verl ag , Berl i n .

67 ) Gri ce , K . A . Mea surement of transepi derma l water l os s . I n : Phys i o l ogy

and Pathophys i o l ogy of the S k i n V I , pp 2 1 16- 2 1 18 ( 1980 ) . Ed i tor : A .

Jarret . Academ i c Pres s , London .

68 ) Bettl ey , F . R . , Gri ce , K . A . , A method for measuri ng the transep i derma l

water l oss and a means of i nacti vati ng sweat g l and s . Br . J . Derm . 77 :

627-638 ( 1965 ) .

69 ) I d son , B . Percutaneous absorpti on . J . Pharm . Sci . 64 : 901-924 ( 1975 ) .

70 ) Scheupl ei n , R . J . S k i n permeati on . I n : P hys i o l ogy and Pa thophysi ol ogy

of the S k i n V , pp 1693- 1730 ( 1 976 ) Ed i to r : A . Jarret . Academ i c Pres s ,

London .

7 1 ) Brebner , D . F . , Kers l ake , D . M . Waddel l , J . L . The d i ffu s i on of water

vapour through human s k i n . J . P hys i ol . 132 : 2 25-231 ( 1956 ) .

7 2 ) Tregear , R . T . Mol ecul ar movement . I n : Phys i ca l Functi ons of S ki n ,

Vol . 5 , p p 46-48 ( 1 966 ) . Academ i c Press , London .

7 3 ) Burch , G . E . , Wi nsor , T . Rate of i nsens i b l e persp i rat i on l ocal l y

through l i v i ng and dead human s k i n . Arch . I n t . Med . 74 : 437-444

( 1946 ) .

7 4 ) Ga l ey , W . R . , Lons dal e , H . K . , Nach t , S . The i n v i tro permeabi l i ty of

s k i n and buccal mucosa to sel ected drugs and tri tated water .

J . I nves t . Derm . 67 : 7 13 - 7 1 7 ( 1976 ) .

7 5 ) Spru i t , D . The measurement and the regenerati on of the water vapor

l oss of human s k i n , pp 9-20 ( 1969 ) Thes i s Offset mi nOpri n t , N i jmegen .

7 6 ) Tregea r , R . T . Mol ecu l ar movement . I n : P hys i ca l Funct i ons of the

S k i n , Vol . 5, pp 6- 1 1 ( 1966 ) Academ i c Pres s , London .

7 7 ) Spru i t , D . The measurement and the . regeneration of the water vapor

l oss of human s k i n , pp 77-93 ( 1969 ) Thes i s Offset mi nOpri n t ,

N i jmegen .

7 8 ) Ma l ten , K . E . Thoughts on i rri tant contact dermat i ti s . Contact Derma-

59

t i t i s 7 : 238-247 ( 1981 ) .

7 9 ) Ummenhofer , B . Hornsch i chtphys i o l og i s che Grund l agen der Praventi on

und Rehabi l i tat ion von Berufsekzemen . Derma tosen 29 : 102- 106 ( 1 981 ) .

80 ) Eb l i ng , F . J . G . D i sorders of Sweat G l ands . I n : Textbook of Dermato­

l ogy , pp. 1675- 1680 ( 1979 ) Edi tors : A. Rook , D . S . Wi l k i nson , F . J . G .

Eb l i ng . B l ackwel l Sc ient ifi c Pub l i cat i ons , Oxford .

81 ) Jenki nson , D . M . Comparat i ve phys i o l ogy of sweat i ng . Br . J . Derm . 88 :

397- 406 ( 1 973 ) .

8 2 ) Bel l , M . The u l tras tru cture of human axi l l ary apocri ne g l ands after

epi nephr i ne i nj ect ion . J . I nves t . Derm . 63 : 147 - 1 59 ( 1974 ) .

83 ) Cag e , G . W . Eccri ne and apocri ne secretory g l ands . I n : Dermatol ogy

i n general med i c i ne ( 197 1 ) Edi tors : T . B . Fi tzpatr i c k , K . A . Arndt ,

W . H . C l ark , A . Z . E i sen , E . J . van Scott , J . H . Vaughan . McGraw-Hi l l

Book Company , New Yor k .

84 ) Kl i gman , A . M . , Shehade k , N . Pub i c apocri ne g l ands and odor . Arch .

Derm . 89 : 46 1-462 ( 1964 ) .

8 5 ) Morimoto , T . T he eccr i ne and apocri ne g l ands and thei r funct i on . I n :

P hys i o l ogy and Pathophys i o l ogy of the Ski n V , pp 1623- 1663 ( 1 978 )

Ed i tor : A . Jarret . Academ i c Pres s , London .

86 ) S i l ver , A . , Montagna , W . , Versac i , A . The effect of denervat i on on

sweat g l ands after epi nephri ne i nj ect i on . J . I nves t . Derm . 42 :

307-324 ( 1964 ) .

87 ) Da l e , H . H . , Fel dberg , W . The chemica l transm i s s i on of secretory

i mpu l ses to the sweat g l ands of the cat . J . Phys i o l . 82 : 1 2 1 - 128

( 1964 ) .

88 ) Sato , K . The phys i ol ogy , pharmacol ogy and b i ochemi stry of the eccri ne

sweat g l ands . Rev . P hys i ol . B i ochem . Pharmaca l . 7 9 : 5 1 - 1 3 1 ( 1977 ) .

89 ) Uno , H . , Montagna , W . Cathechol ami ne-conta i n i ng nerve termi na l s of

the eccr i ne sweat g l ands of Macaques . Cel l . Ti s s . Res . 158 : 1 - 13 ( 1975 ) .

90 ) Kuno , Y . Human Perspi rat ion , p p 347-353 ( 1956 ) Ed i tor : R . F . P i tts ,

C . C . Thomas . Spri ngfi el d , I l l i no i s .

9 1 ) Th i e l e , F . A . J . , Reay , D . A . , Ma l i , J . W . H . Poss i b l e contri buti on to

heat trans fer through the human s k i n by the eccr i ne ( atri ch i a l )

sweat g l and . I n : Handbuch der Haut und Gescnl echtskrankhei ten ; ( 1981 )

Norma l e und Pathol og i sche Phys i ol og i e der Haut I I I ; Ed i tor : J .

60

Jadassohn , Spri nger Verl ag , Berl i n .

92 ) Thi el e , F . A . J . , Ma l ten , K . E . I nsens i b l e water l os s . Transacti ons

St . John ' s Hos p i ta l . Soc . 58 : 199- 2 1 7 ( 1972 ) .

93 ) Matol tsy , A . B . , Bal samo , C . A . A study of the compounds of the

corn i fi ed epithel i um of human s k i n . J . Bi ophys i c . and Bi ochem .

Cyto l . 1 : 339-361 ( 1 955 ) .

94 ) Chr i s tophers , E . , Laurence , E . B . Ki net i cs a nd structura l organ i s a­

t i on of the epi dermi s . I n : Curr . Probl . Derma tol . , Vol 6, pp

87- 104 ( 1976 ) Ed i tor : J . W . H . Ma l i . Karger , Base l .

9 5 ) Kl i gman , A . M . , The b i o l ogy of the stratum corneum . I n : The epi der­

mis pp 387-433 ( 1 964 ) Edi tors : W . Montagna , W . C . Lobi tz .

Academi c Press , New York .

96 ) Ha l pri n , K . P . Epi derma l ' turnover t ime ' - a re-exami nati on . Br .

J . Derm . 86 : 14- 1 9 ( 1972 ) .

97 ) Bl an k , I . H . T he s k i n as an organ of protecti on agai n st the

external envi ronment . I n : Dermatol ogy in general med i c i ne , pp

102- 106 ( 19 79 ) Ed i tors : T . B . F i tzpatri ck , A . Z . E i sen , K. Wol ff ,

J . M . Freedberg , K . F . Austen . McGraw- H i l l Book Company , New Yor k .

98 ) Odl ang , G . F . , H i stol ogy a n d f i ne s tructure o f the epi dermi s . I n :

The s ki n , pp 28-46 ( 1 97 1 ) Edi tors : E . B . Helwi g , F . K . Mostofi .

The Wi l l i ams & Wi l ki ns Company , Ba l ti more .

99 ) Eb l i ng , F . J . G . , Rook , A . D i s orders of kerati ni zat ion . I n : Textbook

of Dermatol ogy , p . 1 259 ( 1979 ) Edi tors : A. Rook , D . S . Wi l ki nson ,

F . J . G . Ebl i ng . Bl ackwel l Sci enti f i c Pub l i cati ons , Oxford . 100 ) Menton , D . N . , E i sen , A . Z . Structure and organ i zat ion of mammal i an

stratum corneum . J . U l trastruct . Res . 3 5 : 247 - 264 ( 197 1 ) .

101 ) Yard l ey , H . J . , Summerl y , R . L i p i d compos i ti on and metabo l i sm i n

normal and d i seased epi dermi s . Pharma c . Ther . 1 3 : 357- 383 ( 1981 )

102 ) Th i el e , F . A . J . , Mal ten , K . E . Eva l uat ion of s k i n damage I . Br . J .

Derm . 89 : 373-382 ( 1973 ) .

103 ) Mal ten , K . E . , Th i e l e , F . A . J . Eva l uat ion of s k i n damage I I . Br . J .

Derm . 89 : 565- 569 ( 197 3 ) .

1 04 ) Sweeney , T . M . , Downes , A . M . , Matol tsy , A . G . The effect of DMSO on

the epi dermal water barr i e r . J . I nves t . Dermato l . 46 : 300-302

( 1966 ) .

6 1

105 ) Scheupl e i n , R . , Ros s , L . Effects of surfactants and sol vents on the

permeabi l i ty of the epi dermi s . J . Soc . Cosmet . Chern . 21 :

853-873 ( 1 970 ) .

106 ) Spru i t , D . , Mal ten , K . E . The regenerat ion rate of the water va pour

l oss of heav i ly damaged s ki n . Dermatol og i ca 1 3 2 : 1 1 5- 123 ( 1 966 ) .

107 ) Val k , P . G . M . van der , Nater , J . P . , B l eumi n k , E . S k i n i rri tancy of

surfactants as assessed by water vapour l oss measurements . J .

I nvest . Derm . 82 : 291-293 ( 1 984 ) .

108 ) Val k , P . G . M . van der , Cr i j ns , M . C . , Nater , J . P . , B l eum i n k , E . S k i n

i rri tancy o f commerc i a l ly ava i l ab l e soap and detergent bars a s

measured by water vapour l os s . Dermatosen 3 : 87-90 ( 1 984 ) .

109 ) Montagna , W . , Hu , F . , G i a cometti , L . Genera l morpho l ogy . I n : U l tra­

structure of norma l and abnormal s k i n , pp 1-20 ( 1 967 ) Ed i tor : A . S .

Zel i ckson . Lea & Febi ger , P h i l adel ph i a .

1 10 } Mal ten , K . E . , Spru i t , D . , Boemaars , H . G . M . , Kei zer , M . J . M . Horny

l ayer i nju ry by sol vents . Berufsdermatosen 1 6 : 135- 147 ( 1 968) .

1 1 1 ) S ims , R . T . The epidermi s . I n : An i ntroducti on to the b i o l ogy of the

s k i n , pp 6 1 - 7 5 ( 1970 ) Edi tors : R . H . Champ i on , T . G i l l man , A . J . Rook ,

R . T . S i ms . Bl ackwe l l S c i en t i f i c Publ i cati ons , Oxford .

1 1 2 ) G i l l man , T . Derma-epi dermal i nterpl ay wi th spec i a l reference to the

heal i ng of cutaneous i nj ur ies and to carci nogenes i s . I n : An i ntro­

duction to the b i ol ogy of the s ki n , pp 3 18-341 ( 1970 ) Edi tors :

R . H . Champi on , T . G i l l man , A . J . Rook , R . T . S ims . B l ackwe l l

Sc i ent i f i c Publ i cati ons , Oxford .

1 1 3 ) Jarret , A . The epi dermi s and i ts re l ati ons wi th the dermi s . I n :

The Phys i o l ogy and Pathophys i ol ogy o f the S ki n , Vol I , p p 3-42

( 1 97 3 ) Ed i tor : A . Jarret . Academ i c P ress , London .

1 14 ) Fros t , P . , Wei nstei n , G . D . , Bothwel l , J . W . , Wi l nauer , R . I ch thyos i ­

form Dermatoses I I I . Stud i es of transepiderma l water l os s . Arch .

Derm . 98 : 230-233 ( 1 968 ) .

1 1 5 ) Gri ce , K . , Satta r , H . , Baker , H . The cutaneous barr i er to sa l ts and

water in psori a s i s and in normal s k i n . Br . J . Derm . 88 : 459-462

( 1 973 ) .

1 16 ) P i n kus , H . Eczematou s ti ssue react ions . I n : A gu ide to dermato-

62

h i stopathol ogy , pp 95- 1 06 ( 1969 ) Ed i tor : A . H . Mehregan . Mered i th

Corporati on , New Yor k .

1 1 7 ) Kl i gma n , A . M . Cutaneous tox i col ogy ; a n overv i ew from the unders i d e .

I n : Curr . Probl . Dermatol . , V o l I , p p 1 - 25 ( 1978 ) Edi tor : J . W . H .

Ma l i . Karger , Basel .

1 18 ) Kl i gman , A . M . , Wood i ng , W . M . A method for the measurement and eva­

l uat i on of i rri tants on human s ki n . J . I nves t . Derm . 49 : 78-94

( 1967 ) .

1 19 ) Na ter , J . P . , Groot , A . C . de . Local s i de effects of top i ca l drugs .

I n : Unwanted effects of cosmeti cs and drugs used i n derma tol ogy ,

pp 1 - 28 ( 1983 ) Excerpta Med i ca , Amsterdam , Oxford .

120 ) Berman , B . , France , D . S . , G i org i o , B . A . , Mar t i nel l i , P . , Hars , A .

Modu l at i on o f express i on o f epi derma l Langerhans cel l properti es

fol l owi ng i n s i tu exposure to g l ucocorti cos tero ids . J . I nvest . Derm .

80 : 168- 1 7 1 ( 1983 ) .

1 2 1 ) Baer , R . L . , G i g l i , I . Al l erg i c eczematous contact dermat i ti s . I n :

Dermatol ogy i n genera l med i c i ne , pp 5 12-519 ( 1979 ) Edi tors : T . B .

Fi tzpatri ck , A . Z . E i sen , K . Wol ff , J . M . Freedberg , K . F . Aus ten .

McGraw- Hi l l Book Company , New Yor k .

122 ) Kl i gman , A . M . T h e i denti fi cat i on o f contact a l l ergens by human

assay I I Factors i nfl uenc i ng the i nduction a nd measurement of

a l l erg i c contact dermati t i s . J . I nvest . Derm . 47 : 375- 392 ( 1966 ) .

123 ) Lanti nga , H . , Nater , J . P . , Coenraads , P . J . Preval ence , i nc i dence ,

and course on the hands and forearms i n a samp l e of the general

popu l ati on . Contact Dermati t i s 10 : 135- 139 ( 1984 ) .

1 24 ) Gri ce , K . A . Transepi derma l water l os s . I n : The Phys i o l ogy and

Pathophys i o l ogy of the Ski n , vol 6 , pp 212 .1 - 2 1 27 ( 1980 ) Edi tor :

A . Jarret . Academ i c Press , London .

1 25 ) Gri ce , K . A . , Satta r , H . , Sharra t , M . , Baker , H . S k i n temperature

and transepiderma l water l os s . J . I nves t . Derm . 57 : 108- 1 10 ( 197 1 ) .

1 2 6 ) Math i a s , C . G . T . , Wi l son , D . M . , Mai bach , H . I . Transepi derma l water

l os s as a funct i on of s k i n temperature . J . I nvest . Derm . 7 7 : 219-

220 ( 1981 ) .

1 27 ) Th i el e , F . A . J . , Senden , K . G . van . Rel a t i ons h i p between s k i n tempe­

rature and the i nsens i b l e pers p i ra t i on of human s ki n . J . I nves t .

63

1 28 ) Rothman , S . The ro l e of the s k i n i n thermoregu l at i on : Factors i nf l u ­

enc i ng s k i n surface temperature . I n : Phys i o l ogy and Bi ochem i s try of

the Sk i n , pp 258-260 ( 1 954 ) The Uni vers i ty of Ch i cago Press , Chi ca­

g o .

129 ) Rothman , S . Nonnervous eccr i ne swea t i ng . Nervous sweati n g . I n : Phy­

s i o l ogy and Bi ochem i s try of the Sk i n , pp 1 6 1 - 162 , 168- 1 78 ( 1 954 )

The Uni vers i ty of Ch i cago Press , C h i cago .

130 ) S ha h i du l l ah , M . , Raffl e , E . J . , Frai n-Bel l , W . , R immer , A . R . Di u rna l

var iat i on i n transepi derma l water l oss . Br . J . Derm . 81 : 866-867

( 1969 ) .

1 3 1 ) Warndorff , J . A . De reacti es van de zweetkl i eren op st imu l ati e met

acetyl -chol i ne . Een onderzoek b i j a topi sche en ni et-atopi sche derma­

tol og i s che pati enten en b i j gezonde proefpersonen . I n : Conti nue

reg i s trat i e van zweetsecreti e , pp 20-60 ( 1 972 ) Brakkens tei n , N i jme­

gen .

132 ) Zol l ner , G . , Thauer , R . , Kaufma n , W . Der i nsens i b l e Gewi chtsverl ust

a l s Funkt i on der Umwel tbed i ngungen . Pfl Ugers Arc h i v 260 : 26 1-273

( 1 955 ) .

1 33 ) Gri ce , K . A . , Satta r , H . , Bake r , H . Effect of ambi ent humi d i ty on

transepi derma l water l os s . J . I nvest . Derm . 58: 343- 346 ( 1 972 ) .

1 34 ) Hal e , F . C . , Westl and , R . A . , Tayl o r , C . L . Barometri c and vapor pres­

sure i nf l uences on i nsens i b l e wei ght l os s . J . Appl . Phys i o l . 1 2 : 20-

28 ( 1 958 ) .

135 ) Hammarl und , K . , N i l sson , G . E . , Oberg , P . A . , Sed i n , G . Transepiderma l

water l oss i n newborn i nfants I . Rel ati on to ambi ent humi d i ty and

s i te of measurement and estimati on of tota l transep i derma l water

l os s . Thes i s I I I pp 1-32 ( 1 977 ) Zata Tryc keri erna , L i n kopi ng .

1 36 ) Bett l ey , F . R . , Gri ce , K . A . The i nfl uence of amb i ent humi d i ty on

transepi derma l water l os s . Br . J . Derm . 79 : 575- 581 ( 1 967 ) .

1 3 7 ) Z i j l stra , W . G . , Brunst i ng , J . R . , Ten Hoar , F . , Mook , G . A . , R i s pens ,

P . Energ i ewi s sel i ng , voed i ng , temperatuurregel i ng . I n : Fys i o l og i e

van het i nterne m i l i eu , p p 260-269 ( 1973 ) V a n Gorcum & Camp . B . V . ,

Assen .

1 38 ) Operati on manua l . Evapor i meter Ep1 , October 1 97 7 . Operati on manual

Servo Med AB , Sweden .

64

139 ) Spru i t , D . The mea surement and the regenera t i on of the water l os s

o f human s k i n . D i ssertat i o n , offsetdru kkerij mi nOpr i nt , N i jmegen ,

2 1 -27 ( 1 969 ) .

1 40 ) N i l sson , G . E . Mea su rement of water exchange through s k i n . Med . B i o l .

Eng . & Comput . 1 5 : 209- 218 ( 1977 ) .

1 4 1 ) Tay l or , C . L . , Buettner , K . I nfl uence of evaporat ive forces u pon

s k i n temperature depend ency of human pers pi rat i on . J . Appl . P hys i o l .

6 : 1 1 3 - 1 23 ( 1 953 ) .

142 ) Wegg , P . , Garl i nton , L . N . , Schwarz , M . J . I nsens i b l e we i ght l os s at

h i g h s k i n temperatures . J . Appl . Phys i o l . 1 1 : 4 1 -44 ( 1 957 ) .

1 43 ) Zoon , J . J . , Mal i , J . W . H . The i nfl uence of erythroderma on the body .

Arch . Derm . 7 5 : 573-578 ( 1 957 ) .

1 44 ) Heerd , E . , Ohara , K . E i n gerit zure u nunterbrochenen Mes sung der

Persp i rat io i nsens i b i l i s k l ei ner Hautfl ichen . Pfl ugers Arch i v .

27 2 : 23 7-246 ( 1961 ) .

145 ) Adams , T . , Funkhou ser , G . E . , Kenda l l , W . W . Measurement of evapora­

t i ve water l os s by a therma l conduct i v i ty cel l . J . Appl . P hys i o l .

1 8 : 1 291 - 1 293 ( 1963 ) .

1 46 ) Wi l son , J . S . , Moncr i e f , J . A . Vapor pressure of norma l and burned

s k i n . Ann . Surg . 1 6 2 : 130-134 ( 1965 ) .

147 ) Rosenberg , E . A . , B l a n k , H . , Resn i k , S . Swea t i ng and water l os s

through the s k i n . J . A . M . A . 1 7 9 : 809-81 1 ( 1962 ) .

148 ) Th i el e , F . A . J . , Schutter , K . A new mi cro method for measu ri ng the

water-ba l a nce of the human s k i n . Sa l t crysta l method . J . I nv . Derm .

3 9 : 95- 1 1 1 ( 1962 ) .

1 49 ) Fal l o n , R . H . , Moyer , C . A . Rates of i nsens i b l e pers p i rati o n through

norma l , bu rned , tape str i pped , and ep iderma l ly denuded l i v i ng human

s k i n . Ann . Surg . 1 58 : 9 1 5-923 ( 1963 ) .

1 50 ) Burch , G . E . , Sodeman , W . A . Reg i onal rel ati ons h i ps of rate of water

l os s i n norma l adu l ts i n a subtropica l c l imate . Am . J . P hys i o l .

1 38 : 603-609 ( 1943 ) .

1 5 1 ) Neumann , C . , Cohn , A . E . , Burch , G . E . A quant i ta t i ve method for the

measurement of the rate of water l os s from sma l l areas , wi th resu l ts

for f i nger t i p , toe t i p and postero - superi or porti on of the p i nna

of normal rest i ng adu l ts . Ame r . J . P hys i o l . 1 3 2 : 748-756 ( 1 941 ) .

65

1 5 2 ) Bu l l ard , R . W . Conti nuous record i ng of swea t i ng rate by res i s tance

hygrometry . J . Appl . Phys i o l . 17 : 7 3 5-737 ( 1 962 ) .

153 ) Rovens ky , J . , Sax l , 0 . D i fferences i n the dynam i cs of sweat se­

cret i on in atopi c ch i l dren . J . I nv . Derm . 43 : 1 7 1 - 176 ( 1 964 ) .

1 54 ) Lamke , L . An i nstrument for estimati ng eva pora t i on from sma l l s k i n

surfaces . Scand . J . P l as t . Reconstr . Surg . 4 : 1 - 7 ( 1 970 ) .

1 5 5 ) Cohen , S . An i nvest i g ati on and fract i onal asses sment of the eva­

porat i ve water l os s through norma l s k i n and burn eschars u s i ng a

mi crohyg rometer . P l as t . and Reconstr . Surg . 37 : 475- 486 ( 1 966 ) .

1 56 ) Spru i t , D . Measu rement of the water vapour l oss from human s k i n by

a therma l conduct i v i ty ce l l . J . Appl . Phsyi o l . 23 : 994-997 ( 1967 ) .

1 57 ) Al bert , R . E . , Pa l mes , E . D . Evaporat ive rate patterns from sma l l s k i n

areas a s measured by a n i nfrared gas ana lyzer . J . Appl . Phys i ol .

4 : 208- 2 1 4 ( 1 95 1 ) .

1 58 ) P i r l et , K . E i ne Methode zur Hautwass erabgabe i n k l e i nen Hautarea l en .

Arch . ges . Phys i o l . Pfl Uger ' s 273 : 182- 180 { 1 961 ) .

159 ) N i l s son , G . E . , Oberg , P . A . A new method for measu rement of trans­

epi derma l water l os s . 3rd . Nord i c Meeti ng on Med i ca l & B i o l og i ca l

Eng i neer i ng , Tampere , 53 : 53 . 1- 53 . 3 ( 1975 ) . 1 60 ) N i l sson , G . E . On the measurement of evaporat ive water l os s , thes i s ,

Zata Trycker i erna , L i n kopi ng , 9-42 ( 1977 ) .

1 6 1 ) Whel don , A . E . , Montei t h , J . L . Performance of a s k i n evaporimeter .

Med . & B i o l . Eng . & Compu t . 1 8 : 201 - 205 ( 1 980 ) .

1 6 2 ) Hatt i ng h , J . , Luc k , C . P . A sens i ti ve , d i rect method for het measure­

ment of water l os s from body su rfaces . S . Afr . J . Med . Sci . 38 :

3 1 - 3 5 ( 1973 ) .

163 ) Carnes , R . W . , So l l ec i to , W . A . , Sa l i s bury , R . E . Evaporat i ve water

l oss from hea l ed burn wou nd s . Journa l of Burncare and Rehab i l i ta­

t i on , val . 2 No 5 : 239-245 ( 1 981 ) .

164 ) Scott , R . D . , O l i ver , G . J . A . , Dugard , P . H . , S i ng h , H . J . A compari son

of techni ques for the measurement of transepi dermal water l os s .

Arc h . Dermato l . Res . 274 : 57-64 ( 1 982 ) .

165 ) N i l sson , G . E . A theoret i ca l compar i son of the measurement sen s i t i v i ­

ty of d i fferent methods for measurement of evaporati on ( 1976 ) .

Publ i cat i on L i n kopi ng Un i vers i ty , Department of med i ca l engi neeri ng ,

66

Sweden .

1 66 ) Lamke , L . O . , N i l s son , G . E . , Rei thner , H . L . I nsens i b l e pers p i rat i on

from the s k i n u nder standardi zed envi ronmental cond i t i ons , thes i s ,

G . E . N i l s son , ( 1 977 ) Zata Trycker i erna , L i n kopi ng .

67

CHAPTER 2

SK IN I RR ITANCY OF SURFACTANTS AS ASSESSED BY WATER VAPO UR LOSS

MEASURE�iENTS

Journnl of I nvest igat ive Dermatol ogy

82 : 291-293 ( 1 984 )

68

Authors :

P . G . M . van der Val k

J . P . Nater

E. B l eumi nk

Summary

A method to assess the i rr i tancy of c hemi cal s on human s k i n that i s based

on measu rement s of s k i n (water ) vapor l oss ( SVL ) i s presented . The SVL

measurements were performed with the Servo Med Evapori meter in a group of

27 hPul thy vol unteers . Four surfactants , d i st i l l ed water . and NaCl 0 . 9%

i n d i sti l l ed water were assayed . For the exposures a chamber techni que

was used . Sod i um l auryl s u l fate and cocobet a i ne most marked ly i nfl uenced

the l oss of water through the s ki n . Pol ysorbate-60 and sodi um l aurate had

l ess effect on SVL . The mean d i fference between the test substances were

fou nd stat i st i ca l ly s i gn i f i cant , except for the mean d i fference between

sod i um l aurate and pol ysorbate-60 ( p > 0 . 1 ) and between polys orbate-60

and di sti l l ed water ( p > 0 . 05 ) . The reacti ons of the tested subj ects to the surfactants suggest that each i nd i v i dua l has h i s own pattern of sus­

cepti b i l i ty to these substances . The mean va l ues of the SVL measurements

were compared w ith the macroscopi ca l l y percept i b l e morpho l og i c changes of

the exposed test s i tes . The resu l ts of the v i sua l scori ng system corres­

ponded w ith the resu l t s of the SVL measu rements . The correl at i on coeffi ­

c i ent between the mean val ues of both methods was found to b e h i gh ( r =

0 . 98 ) .

I ntroducti on

The i nfl uence of surfactants on the s k i n can be s tud i ed in d i fferent ways .

I n exposure tests , by g i v i ng a test panel a cert a i n product for a l ength

of t ime , i nterven i ng var iab l es hamper i n terpretat i on of the resu l t s ( 1 , 2 ) .

A more rel i abl e techn i que for eva l uati ng s k i n i rr i tancy of c l eansers i s

the soap chamber tes t , ut i l i z i ng a v i sual scori ng system ( 1 ) . Al though

macroscop i cal ly percept i b l e changes of the s k i n observed w i th thi s method

more or l ess corres pond w ith the c l i n i ca l p i cture of eczema , the method

i s not very obj ect i ve and i s prone to i nterobserver b i a s ( 3 , 4 ) . Moreover ,

unphys i o l og i cal ly h igh concentrati ons of soaps or detergents have to be

used to produce d i scern i b l e reacti ons of the s k i n ( 5 ) . Another method for

eva l uati ng the: i nfl uer 1ce of chem i c a l substances i s a ssessment of d i stur­

bances in uarri er capaci ty of the s k i n ( 6 , 7 ) . Techn i ques to eva l uate the

69

barri er capaci ty are measu rements of s k i n i mpedance and water vapor l oss

( 6 ) . The l atter techn i que i s i ncreas i ng ly u sed to study the s k i n tox i c i ­

ty o f chemi cal substances , a l though there i s st i l l some controversy about

th i s method ( 2 , 5-9 ) .

We want to present a s k i n vapor l oss ( SVL ) method wi th wh i ch the effect

of exposure on the s k i n to mi l d i rr i tants can be measured .

Materi a l s and methods

For the exposu re , the l arge F i nn chamber wa s uti l i zed - an a l umi n i um cup

wi th a d i ameter of 12 mm ( Ep i tes t , Hel s i n ki , F i n l and ) ( 10 ) . F i ve pi eces

of absorbi ng paper ( Whatman ) were fi tted i nto each chamber wh i ch subse­

quently received 100 �L of a 2 g/ 100 ml i n d i sti l l ed water by mea ns of an

Oxford pi pette ( Oxford Lancer , Brunswi ck Company , St . Loui s , Mi ssouri ) .

The chambers were appl i ed pa i rwi se to the vol ar s i de of the forearm by a

sma l l pi ece of non i rri tat i ng Leukos i l k tape ( Bei ersdorf , Hamburg , Germa­

ny ) . Fi xati on was assured by the use of Mol l e l ast el asti c gauze bandages

( Lohmann , Neuwi ed , Germany ) .

A panel of 27 heal thy vol unteers wi thout s k i n ai l ments ( 8 women and 19

men , rang i ng in age from 21-32 years ) were tes ted dur i ng the month of De­

cember. The s k i n wa s exposed to the tes t substances duri ng a peri od of

24 h . An off- peri od of 1 h before the actual SVL mea surements was empl oy­

ed to reduce the effects of macerat ion and desorpt i on after the arti f i c i ­

a l hydrati on , wh i ch m ight i nfl uence the resu l ts ( 1 1 ) .

Prior to the SVL measu rements the test s i tes were graded for erythema ,

scal i ng , and f i s suri ng accord i ng to a method descri bed by Frosch and Kl i g­

ma n ( 1 ) . Erythema : 1+ , s l ight redness , spotty of d i ffus e ; 2+ , moderate

rednes s ; 3+ , i ntense rednes s ; 4+ , f i ery red wi th edema . Scal i ng : 1+ , f i ne

cracks ; 2+ , s i ng l e or mu l t i p l e broader f i s sures ; 3+ , wide cracks wi th he­

morrhage or exudat ion .

After the 1- hour off- peri od a prel imi nary t i me of 1 5 m i n was kept before

the actual measurements were i n i t i ated i n order to reduce effects of ther­

mi c and emot i ona l sweat i ng ( 1 1 ) .

The quant i tat ive measurements of evaporat i ve water l os s were carr i ed out

u s i ng the Servo Med Evaporimeter ( Servo Med , Stockho l m , Val l i ngby , Sweden ) .

70

Thi s i nstrument uses the method of g rad i ent estimati on des cri bed i n deta i l

by N i l sson ( 12 ) . The operat i ng pr i nc i p l e of t h i s method i s based on ca l ­

cu l at i on of the vapor pressure g rad i ent i n the l ayer adj acent to the s k i n .

The pres sure gradi ent i s w i t h i n a stati onary l ayer of a i r surround i ng the

human body proporti onal to the exchange of water vapor from the s k i n sur­

face . The actual i nstrument compr i s es a hand- hel d probe attached to a por­

tab l e d i s p l ay uni t . Duri ng the SVL measurements a hol der was used for the

probe to prevent warmi ng up and to make some maneuveri ng poss i b l e . After

app l yi ng the probe perpend i cu l ar to the s k i n surface , stabi l i zation of

the d i s p l ayed val ues was awa i ted . The m idpo i nt va l ue of a 1 5-s . SVL reg i s­

trat i on was ta ken as a typ i ca l score for the tes ted s k i n s i te . Measu re­

ments were carri ed out on exposed and on 6 unexposed adj acent s k i n s i tes .

The measu rements of SVL were performed i n a tempera tu re-control l ed room

( 22° C ) wi th a rel a ti ve hum i d i ty of 28 . 7 ± 5 . 0% . Duri ng the measurements

s k i n temperature was reg i s tered by means of a Yel l ow Spri ngs thermi stor

prox ima l to the tested s k i n area ( Yel l ow Springs I n strument , Yel l ow

Springs ) .

The fol l owi ng 6 substances

sod i um l aury l s u l fate

sod i um l aura te

pol ysorbate-50

cocobeta i ne

di sti l l ed water

NaCl 0 . 9�

were tes ted on both the

a n i on i c surfactant

ani oni c surfactant

noni on i c surfactant

amphoteri c surfactant

control

control

r i g ht and l eft arms :

( pH 7 . 3 )

( pH 9 , 2 )

( pH 3 . 8 ) ( pH 5 . 2 )

( pH 5 . 6 )

( pH 6 . 7 )

These surfactants were sel ected because of the d i fferences i n chemi ca l

properti es and on the bas i s of frequency of use in commerc i a l l y avai l ab l e

products .

Stat i sti ca l Methods

The observed frequency d i s tr i but i ons of SVL data of the d i fferent test

s i tes were stud i ed for c l ear dev i ances from norma l i ty (Gau s s i an d i stri bu­

t i on ) by means of Kol mogorov- Smi rnov one-samp l e tes t .

I n compar ing the d i fferent test substances the mean SVL va l ues were eva l u­

ated for s i gn i f i cant d i fferences u s i ng a t-tes t for pai red data (a=0 . 05 ) .

71

The var i a ti on of the SVL val ues was ana lyzed by est imati ng one person ' s

SO ( cr = IMSr ; MSr = res i dua l mean sum of squares ) and that between per­

sons ' SD ( cra = /(MSa - MSr ) / 2 ; MSa = i ntersubj ect mean sum of squares ) .

The morphol og i c changes of the s k i n after exposure of the test subs tances

were eval uated by cal cu l ati ng an " overa l l score " for each i nd i v i dua l test

s i te from the scores for erythema , fi ssuri ng , and sca l i ng as graded by

Frosch and Kl i gman ( 1 ) . Di fferences between the test substances as asses­

sed by th is v i sual scor i ng system were tes ted by means of the Wi l coxon

s i gned rank sum test for pai red data u s i ng the mean of the overa l l scores

( a = 0 . 05 ) .

The test substances were ranked accord i ng to the mean SVL as wel l as the

mean overal l score of the morpho l og i c changes of the sk i n . Pearson ' s pro­

duct-moment correl at i on between the mean scores of both methods was ca l ­

cu l ated .

Resu l ts

I n Tab l e I the SVL val ues of exposed and u nexposed s k i n s i tes are summa­

r i zed . The surfactants as wel l as d i st i l l ed water and NaCl 0 . 9% l ed to

an i ncrease of SVL as compared wi th unexpos ed sk i n . Sod i um l auryl su l fate

and cocobeta i ne most marked l y i nf l uenced the l oss of water through the

s k i n whereas pol ysorbate-60 and sod i um l au rate proved to have l ess effect

on evaporati ve wa ter l oss of the s ki n . Consp i cuous is the d i fference be­

tween d i sti l l ed water and NaCl 0 . 9t .

Ana lys i s of the SVL frequency d i stri but i ons ( Kol mogorov- Smi rnov one- sam­

p l e tes t ) d i d not show s i gn i f i cant d i fferences between the observed cumu­

l at i ve frequency di stri buti ons of SVL data and the corres pond i ng ( theore­

t i ca l ) cumu l at i ve frequency d i stri but i on of normal ly d i stri buted data .

I n v i ew of these data di fferences between the tes t substances , they were

tested by means of a t-test for pai red data . Al l the mean d i fferences be­

tween the test substances were s i gn i f i cant , except for the mean d i fferen­

ce between sod i um l aurate and pol ysorbate-50 ( p > 0 . 1 ) and the mean d i f­

ference between pol ysorbate-50 and d i sti l l ed water ( p > 0 . 05 ) .

7 2

Tabl e I . Mean s k i n vapor l ossa after a 24-h exposure .

Mean { g/m2h ) SD

1 . SVL after sod i um l auryl su l fate 1 5 . 5 4 . 0

2 . SVL after sod i um l aurate 10 . G 2 . 5

3 . SVL after pol ysorbate-GO 9 . 8 2 . 5

4 . SVL after cocobeta i ne 1 2 . G 2 . 3

5 . SVL after d i st i l l ed water 9 . 2 2 . 1

G . SVL after NaCl 0 . 9.1> 7 . 7 1 . 9

7 . SVL control b G . 2 1 . 3

a Twenty- seven subj ects ; 2 measurements i n 1 subj ect . b Twenty- seven subjects ; G measurements i n subj ect .

Tabl e I I . S i n g l e person s ' and between eersonsa s tandard dev i at i on of

the SVL val ues .

S i n g l e persons ' S D Between person s ' SD

1 . Sod i um l auryl su l fate 2 . 9 3 . 4

2 . Sodi um l aurate 2 . 2 2 . 0

3 . Pol ysorbate-GO 2 . 2 2 . 0

4 . Cocobeta i ne 1 . 8 2 . 0

5 . Di sti l l ed water 2 . 0 l . G

G . NaCl 0 . 91 1 . 5 l . G

a Twenty- seven subj ects ; 2 test s i tes i n 1 subj ect .

73

Di s pers i on of the SVL va l ues

Tab l e I I g i ves a survey of a s i ng l e person ' s SO and the SD between per­

sons for each test substances . Both sources of var iat i on proved to be im­

portant .

I nfl uence of personal and env i ronmental var i ab l es

The i nfl uence of rel evant var iab l es u pon va l ues of unexposed s ki n was

stud i ed . Amb i ent hum i d i ty d i d not i nfl uence SVL i n the obs erved rang e .

The i nfl uence of a i r temperature cou l d not be stud i ed because t h e tem­

perature was a l most constant . Personal ( conti nuous ) var i a b l e l i ke age ,

s k i n temperatu re , and arm c i rcumference at t he test s i te d i d not have a

s i gn i f i cant i nfl uence . Th i s a l so appl i ed for d i screte vari abl e such as

sex , s k i n type , and h i s tory of atopy in th i s grou p .

Compari son o f the S V L method w i t h a v i sua l scor i ng sys tem

I n tabl e I I I the macroscop i ca l ly v i sual changes of the s k i n after expo­

sure to the test su bstances are l i sted . The ar ithmet i c mean of the over­

a l l scores was taken as a measure for the i rri tancy of the test substan­

ces . I t is noteworthy that a s i ng l e 24-h exposure of a 2 g/ 1 00 ml so l u ­

t i on i n d i s t i l l ed water d i d not provoke severe reactions ( 3+ and 4+ ) as

observed by Frosch and Kl i gman ( 1 ) . The d i fferences between the mean

overa l l s cores were tested for s i gn i fi cance ( Wi l coxon ' s s i gned rank sum

test for pai red data ) . Al l mean d i fferences between the tes t substances

were s i gn i f i cant , except for the di fference between sod i um l aurate and

pol ysorbate-60 , sod i um l aurate and d i st i l l ed water (p > 0 . 1 ) , and be­

tween polys orbate-60 and d i s t i l l ed water ( p > 0 . 05 ) .

The mean react i on of the tes ted s k i n s i tes to the chemi ca l s as measured

by the SVL method was compared w i th the mean overa l l s cores . ( F i gs 1 , 2 ) .

The rank order of i rri tancy of the tested substances was equal for both

methods . Correl at i on between the mean scores of both methods was r =

0 . 98 .

Di s cus s i on

The resu l ts of the i nves t i gat ion poi nt out that the descri bed method of

74

Tab l e I I I . Mean scores of the morphol ogi c changes a after a 24-h exposure .

Erythema Sca l i ng F i s s ur i n g " Overa l l

s core"

1 . Sod i um l auryl s u l fate 0 . 926 0 . 093 0 . 167 1 . 833

2 . Sod i um l aurate 0 . 296 0 . 056 0 . 167 0 . 537

3 . Pol ysorbate-60 0 . 352 0 . 000 0 . 074 0 . 462

4 . Cocobeta i ne 0 . 574 0 . 03 7 0 . 204 1 . 093

5 . D i st i l l ed water 0 . 296 0 . 000 0 . 01 9 0 . 333

6 . NaCl 0 . 9% 0 . 1 48 0 . 000 0 . 000 0 . 1 48

a T1�enty- seven s ubjects ; 2 test s i tes i n 1 subj ect .

7 5

SVL measurements to assess the i rri tancy of surfactants i s equ i va l ent to

a v i sua l scori ng system ( soap chamber tes t ) , wi th the advantage that pa­

rametri c analys i s can be used to eva l uate sma l l d i fferences i n i rr i tancy

of the surfactants . Wi th th i s method i t i s pos s i b l e to test surfactants

i n wea k concentrati ons , resemb l i ng da i ly l i fe c i rcums tances .

Al though c l ear d i fferences among the ( genera l ) i rr i tancy of the test sub­

s tances cou l d be noted , con s i derabl e vari a t i on of the SVL val ues was a l so

observed (Tab l e I I ) . Th i s may be expl a i ned i n part by i naccurac i es of the

SVL method (. s i ng l e persons ' var i a t i on of the SVL val ues after exposu re

of the same surfactant ) . Howeve r , d i vergent patterns of SVL val ues cou l d

be observed , probably a l s o contri bu t i ng to the total vari at ion of the re­

su l ts , wh i ch suggest i n ter- and i ntrasubj ect d i fferences in suscept i b i l i ­

ty .

Di fferent damag i ng effects have been descri bed l i ke degrea s i ng of the

s k i n , denaturat ion of kera ti n , wi thdrawa l of the " natural moi ster i ng fac­

tors , " and destabi l i zati on of l ysosomes ( 13 - 18 ) . These effects d i rect ly

or i nd i rectl y ( e . g . , by i nf l ammatory proce sses ) i nfl uence the barr i er

funct i on of the s k i n . Surfactants have d i fferent phys i cochem i ca l proper­

t i e s . Consequent ly each surfactant wi l l penetra te and affect the s k i n to

a certa i n extent a l ong s pec i f i c pathways wi th s peci f i c i nteracti ve and

cumu l ati ve effects , res u l t i ng i n d i sturbances of the barr i er funct i on .

Furthermore , i t i s pos s i b l e that const i tuti onal d i fferences i n s k i n type

cause a s pec i f i c i nd i v i dua l suscept i b i l i ty to the effects of a substance ,

resu l t i ng i n i nter- and i ntras ubject d i fferences i n SVL after exposure .

The pattern of wi dely d i vergent morpho l og i c changes as observed i n the

soap chamber test support th i s hypothes i s .

76

16-l t

14l m, . n 12J S . V . L v a l ues 10

8�

6� �

t

f f f

' +

II I I I .-----J 1 2 3 4 5 6 7

surf a c t a n t s and c o n t r ols

m e a n 'o v e r a l l s c o r e s'

2

f

! t t

� � 2 3 4 5 6 7

surfactants a n d controls

F i g . 1 . S k i n i rr i tancy of the tes ted substances as asses sed by S . V . L . measurements

and by a ' v i s ua l s cor i ng sys tem ' (mean s cores ! S . E . M . ) .

1 . sod i um l aury l s u l fate 2 . sod i um l aurate 3 . polysorbate-60

4 . cocobeta i ne 5 . d i s t i l l ed water 6 . NaCl 0 . 9% 7 . control .

,..... ,..._

16

14

MEAN 12 S V_L VALUES

10

8

I 0, 4

I 0, 8

I 1.2

MEAN 'OVERALL SCORES'

I 1.6

I 2, 0

F i q . I I . Scattergram of the tes ted subs tances ; regres s i on of the

mean S . V . L . wi th the mean ' overal l s core ' of the morpho-

1 og i c changes .

78

References

1 ) Fros c h , P . J . , Kl i gman , A . M . The soap chamber tes t . J . Am . Acad . Der­

matol . 1 : 35-41 ( 1979 ) .

2 ) Ketel , W . G . van , Bruynzeel , D . P . , Bezemer , P . D . , Stamhu i s , I . H . Tox i ­

c i ty o f hand c l eansers . Dermato l og i ca 168 : 94-99 ( 1 984 ) .

3 ) Wah l berg , J . E . Assessment of s k i n i rr i tancy : measurement of s k i n fol d

th i c knes s . Contact Dermat i t i s 9 : 2 1-26 ( 1 983 ) .

4 ) Shel l ow , W . V . R . , Rapa port , M . J . Compari son tes t i ng of soap i rri tancy

u s i ng a l umi n i um chamber and standard patch methods . Contact Derma­

t i t i s 7 : 7 7-79 ( 1 981 )

5 ) Has s i ng , J . H . , Nater , J . P . , B l eumi n k , E . I rr i tancy of l ow concentra­

t i ons of soap and synthet i c detergents as meas ured by s k i n vapour

l os s . Dermatol og i ca 164 : 3 1 4-32 1 ( 1982 ) .

6 ) T h i e l e , F . A . J . , Ma l ten , K . E . Some measuri ng methods for the eva l ua­

t i on of orthoerg i c contact dermat i t i s . Arch . Be l g . Dermato l . 28 : 23-

46 ( 1973 ) .

7 ) Mal ten , K . E . , Arend , J . den . Topi ca l tox i c i ty of var i ou s concentra­

t i on s of DMSO recorded w i th impedance measurements and water vapour

l os s measurements . Contact Dermati ti s 4: 80-92 ( 1978 ) .

8 ) Mal ten , K . E . , Spru i t , D . , Boemaars , H . G . M . , Kei zer , M . J . M . de . Horny

l ayer i nj u ry by so l vents . Berufsdermatosen 16 : 1 35- 147 ( 1978 ) .

9 ) Va l k , P . G . M . van der , Nater , J . P . , B l eumi n k , E . S k i n vapour l os s as a

method for measur i ng the i nfl uence of soaps and detergents on human

s k i n . Derm . Beruf . Umwel t 2 : 58-60 ( 1983 ) .

10 ) P i r i l a , V . Chamber test versus patch test for epi cutaneou s tes t i ng .

Contact Dermati ti s 1 : 48- 52 ( 197 5 ) .

1 1 ) Ba ke r , H . , Kl i gman , A . M . Measurement of transepi dermal water l os s by

el ectri ca l hygrometry . Arc h . Dermatol . 96 : 441-452 ( 1967 ) .

1 2 ) N i l s s on , G . E . Measurement of water exchange through the s k i n . Med .

B i o l . Eng . Comput . 1 5 : 209- 218 ( 1977 ) .

1 3 ) Harrol d , S . P . Denaturat i on of epi derma l kerat i n by surface act i ve

agents . J . I nves t . Dermatol . 3 2 : 581- 588 ( 1959 ) .

1 4 ) Imokawa , G . , M i s h ima , Y . Cumu l at i ve effects of surfactants on cuta­

neous horny l ayers : Lysosome l ab i l i z i ng act i o n . Contact Dermati t i s 5 :

7 9

1 51- 162 ( 1979 ) .

1 5 ) K i r k , J . F . Effect of hand was h i ng on s k i n l i p i d remova l . Acta Derm .

Venereol . ( Suppl . ) ( Stockh . ) 57 : 24-68 ( 1966 ) .

1 6 ) Mal a szk iewi cz , J . Untersuchungen Uber d i e Wi rkung von Ten s i den auf

d i e mensch l i che Haut mi t e i ner Mi kromethode . Arch . Kl i n . Exp . Der­

mato l . 237 : 652-661 ( 1970 ) .

1 7 ) Smeen k , G . The i nfl uence of detergents on the s k i n . Arch . Kl i n . Exp .

Dermato l . 235 : 180- 19 1 ( 1 969 ) .

1 8 . Scott , E . J . van , Lyon , L . 8 . A chem ica l measure of the effect of soap

and detergents on the s k i n . J . I nves t . Dermatol . 2 1 : 199-203 ( 1 963 ) .

80

CHAPTER 3

THE VULNERAB I L ITY OF THE SK IN TO SURFACTANTS IN D I FFERENT GROUPS

OF ECZEMA PAT I ENTS AND CONTROLS AS DETERMINED BY WATER VAPOUR LOSS

Accepted for pub l i cati on i n

C l i n i ca l & Experi mental Dermatol ogy

81

Authors :

P . G . M . van der Va l k

J . P . Nater

E . B l eumi n k

Summary

Hea l thy unaffected s k i n of the vol ar s i d e of the forearm of eczema pa­

t i ents and control s was exposed duri ng a peri od · of 48 hou rs to 100 � 1 of

a 2 g/v% sol ut ion of 8 surfactants and d i sti l l ed water by means of the

l arge F i nn chamber method .

The effect of th i s ' s tandardi zed s k i n i ns u l t ' was eval uated by means of

s k i n water vapour l os s measurements u s i ng the Servo Med Evaporimeter .

Cl ear d i fferences i n react i ons caus ed by the d i fferent surfactants were

observed .

The subgroup of pati ents wi th atopi c derma t i t i s reacted more severe ly

than d id the subgroup of heal thy control s to the syntheti c detergents .

The a l kal i ne soaps were tol erated rel ati ve ly wel l i n th i s grou p .

N o s i gn i fi cant di fferences i n react i on upon exposure to the surfactants

as determi ned by water vapour l os s measurements were noted between the

subgroup of pati ents wi th i rri tant contact dermati ti s and the subgrou p

of heal thy contro l s .

I ntroducti on

If the s k i n is exposed to a proper concen trati on of a surfactan t , func­

ti onal d i s turbances of the s k i n , wh i ch can be assessed by i nterrel ated

parameters such as s k i n impedance , water l os s and carbon d i ox i de rel ease

of the s ki n , occur (Thi el e & Mal ten , 197 3 ; Ma l ten & Thi el e , 1 973a ,

von Ki s s , 1 981 ; v . d . Va l k , 1 984a ) . A l s o tox i c effects can be revea l ed by

means of i n v i vo and i n v i tro methods ( Fros ch , 1982 ; Smeenk , 1969 ) .

Under l aboratory cond i ti ons , th i s react i on represents to a certa i n ex­

tent the s ame mechan i sm as i nvol ved i n i rri tant contact dermati t i s

( Kooyman & Snyder , 1 942 ; Frosch & Kl i gman , 197 9 ) .

I n the past , many aut�ors had a l ready poi nted to a pos s i bl e associ ati on

between the use of soaps and detergents and the devel opment of i rri tant

contact dermati ti s ( Pol ano , 1 968 ; Bettl ey , 197 2 ; Ma l ten , 1981 ) .

I n the s tudy reported here , unaffected s k i n of pati ents wi th various

dermato l og i ca l d i seases and of hea l thy subj ects was exposed to s tan­

dardi zed sol ut ions of d i fferent surfactants i n order to assess the vu l -

82

nerabi l i ty of the s k i n to these subs tances .

The react ion to the surfactants was eval uated by mean s of s k i n water

vapour l os s mea surements u s i ng the Servo Med Evaporimeter ( N i l s son , 1977 ;

v . d . Va l k et a l . , 1 984a ) .

An attempt has been made to rel ate the observed i ncrease of water vapour

l os s after exposure to the surfactants to c l i n i ca l characteri st i c s of

the tested subj ects .

Mater i a l s and methods

The s k i n was exposed to the tes t substances by u t i l i z i ng F i n n chambers of

a d i ameter of 12 mm ( P i r i l a , 1 97 5 ) . Each chamber conta i ned absorb i ng pa­

per wh i ch was s aturated wi th 100 � l of a 2 g/v% so l ut i on .

Four stri ps each cons i s t i ng of three F i nn chambers para l l e l to each other

were appl i ed to the vo l ar s i de of the forearm from proxi ma l l y to d i ­

stal l y . Each tri pl et of chambers con s i sted o f two chambers conta i n i ng a

surfactant and one chamber wi th d i s t i l l ed water . The s k i n was expos ed

duri ng a peri od of 48 hours to the fol l owi ng 8 s u rfactants :

sod i um l au rate a n i on i c pH 9 . 2

sod i um stearate an i on i c pH 10 . 4

s od i um l au ryl su l fate an ion i c pH 7 . 3

pota s s i um soap� a n i on i c pH 10 . 0

cocobetai ne amphoteri c pH 5 . 2

ceteareth- 12 non i on i c pH 6 . 4

cocami dopropy l beta i ne amphoter i c pH 6 . 0

pol ysorbate-60 non i on i c pH 3 . 8

� ) Pota s s i um s a l t of coconut and r i c i nu s o i l .

Water vapour l os s of the 1 2 exposed s k i n s i tes { 8 surfactants and four

contro l s wi th d i st i l l ed water ) and of four unexposed s k i n s i tes adjacent

to the four stri ps was determi ned . The measurements were performed twi ce :

after the 48 hours exposure and 24 hours l ater . Before t he actu a l mea­

surements , there was a wa i t i ng peri od of 15 mi nutes in order to reduce

effects of sweati ng ( Ba ker & Kl i gman , 1 967 ) .

Duri ng the t ime of measurement ( ± 30 m i nutes ) , the rel a t i ve humi d i ty and

83

tempera ture of the ambi ent a i r were con s i dered as constan t .

For t h e quanti tat i ve determi nations o f eva porati ve water l oss , the Servo

Med Evaporimeter was used ( N i l sson , 1977 ; v . d . Va l k et a l . , 1 984a ) .

Test panel

A grou p of 103 subj ects ( 47 fema l es and 56 ma l es rangi ng in age from 19

to 7 2 years ) was tes ted in the l a st f i ve months of 1982 and the f i rst

two months of 1983 .

The panel cons i s ted of the fol l owi ng two groups :

number of subj ects mean age S . D .

1 ) Eczema pat i ents 69 35 . 3 1 3 . 9

2 ) Control s 34 39 . 8 1 3 . 8

The group of eczema pati ents con s i s ted of 5 subgroups :

number of subj ects mean age S . D .

1 ) Al l erg i c contact dermati t i s 14 37 . 2 1 5 . 9

2 ) I rri tant contact dermati t i s 1 7 30 . 7 1 3 . 1

3 ) Atop i c dermati ti s 10 28 . 1 7 . 1

4 ) Dys hi droti c dermati ti s 2 1 36 . 0 1 1 . 4

5 ) Uncl a s s i f i ed eczema 7 52 . 9 1 3 . 1

The c l a s s i fi cati on i nto eczema subgroups was based on h i story , cl i n i ca l

pi cture , i ntracutaneous tes ti ng and patch testi ng . The cri teri a of Fre­

gert ( 1981 ) and Nater & de Groot ( 1982 ) were used for thi s c l a s s i fi ca­

tion . Seven subj ects cou l d not be c l a s s i f i ed i nto one of the maj or ec­

zema categor i es . Al l pati ents wi th eczema were tested i n a qui escent

pha se of the d i seas e .

The group o f control s cons i s ted o f two su bgroups :

1 ) Hea l thy contro l s

2 ) Pati ent cont ro l s

number of s ubj ects

19

1 5

mean age

33 . 5

47 . 8

S . D .

1 1 . 2

12 . 8

The subgroup of heal thy subj ects were ei ther med i ca l s tudents o r emp l oy­

ees of the hos pi tal . The subgroup of pati ent control s con s i s ted of a

84

mi scel l aneous group hav i ng noneczema tous dermatoses ( u l cus cruri s , urt i ­

cari a , psor i a s i s , etc . ) . Di sti ncti on between these two control subgroups

wa s made in order to exc l ude a pos s i b l e i nfl uence of noneczematous de�

matoses of the s k i n e l sewhere on the test resu l ts .

A l l subj ects wi th a dermatol og i ca l d i sease ( eczematous and noneczematous )

were recru i ted from the pati ents v i s i t i ng the outpati ent department of

the c l i n i c for d i agnosti c purposes . The s k i n of a l l tes ted subj ects used

for the exposures and measu rement procedure was { c l i n i ca l l y ) unaffected .

I n most subj ects , the surfactants el i c i ted no v i s i b l e reacti ons or on l y

a s l i ght soap effect ( chappi ng ) . I n some subjects , t h e surfactants ,

wh i ch a l so caused a cons i derab l e i ncrease i n s k i n water vapour l os s ,

caused d i fferent grades of erythema .

Stati s t i ca l methods

The nu l l hypothes i s of no d i fference i n res pons e of the d i fferent groups

of s u bj ects to the surfactants was tested by u s i ng an a pproxi mate F-test

of mu l t i vari ate analys i s of vari ance ( Hu l l & N i e , 1981 ) .

To study d i fferences between the groups , t-tests for unpai red data were

performed . D i fferences between the surfactants i n i nfl uenc i ng s k i n water

vapour l oss were tes ted by u s i ng pai red t-tests .

As the fi rst step of the analys i s , poss i b l e i nfl uences of ambi ent humi ­

d i ty (mean 3 8 . 4� ! 8 . 7 ) and ambi ent temperature (mean 22 . 9°C ± 1 . 5 ) ,

age of the tes ted subj ects , month of tes t i ng , l ocat i on of the test s i tes

on the arm and sex of the tested subjects were assessed . No i nfl uence of

these var iab l es , except for the sex of the tested subjects , was detected

( a = O . D5 ) .

The mean wa ter vapour l os s of unexposed s k i n wa s 6 . 9 g/m2h ± 2 . 4 for 2 + ma l es and 6 . 2 g/m h - 2 . 4 for fema l es . For exposed s ki n , the d i fferences

i n reacti on between ma l es and fema l es were randomly negati ve or pos i ti v e .

These di fferences were not i nvol ved i n the ana l ys i s ( the subgroups were

not domi nated by one of the sexes ) .

85

Resu l t s

The mean evaporative water l oss of the s k i n s i tes exposed to surfactants

and d i sti l l ed water and the mean val ue for the unexposed control s i tes

are l i sted i n Tabl e I for the entire test panel .

The mu l t i var i ate ana lys i s of variance performed on the water l oss data

i nd i cated d i fferences i n reaction to the tested substances among the

di fferent groups ( p < 0 . 05 ) .

To study the d i fferences between the subgrou ps of eczema pati ents and

the subgroup of heal thy contro l s , the mean water vapour l oss va l ues for

corres pond i ng test s i tes were compared . On ly i n the subgroup of pati ents

wi th atop i c dermati t i s were s i g n i fi cant d i fferences observed for the

synthet i c detergent s . Between the three test s i tes expos ed to a l ka l i ne

soaps , the d i fferences proved to be non- s i g n i f i cant i n t h i s group ( Tabl e

I ) .

A s i g n i f i cant d i fference between the group of pati ents wi th atop i c der­

mat i t i s and the heal thy i nd i v i dua l s w ith respect to the control measure­

ments can be seen { d i s ti l l ed water and unexposed sk i n ) .

D i scu ss i on

The subgroup of pat i ents wi th atopi c dermati t i s reacted more severe ly

than d id the group of heal thy contro l s , espec i a l ly to the synthet i c de­

tergents . The a l ka l i ne soa ps were tol erated rel a ti vely wel l i n the sub­

group of atopi c dermati ti s . These fi ndi ngs confi rm the resu l ts of Has­

s i ng et a l . ( 1982 ) , Fros ch ( 1 982 ) , Dyer & Hassapi s ( 1983 ) and van Ketel

et a l . ( 1 984 ) . These authors menti on the good tol erance of a l ka l i ne

soaps , especi a l l y for subj ects with a dry s k i n ( Frosch , 1 982 ) .

I t i s noteworthy that the water vapour l os s of unexposed s k i n i n the

subgroup of pati ents wi th atop i c dermati ti s was a l so s i g n i fi cant ly

h i g her ( p < 0 . 01 ) .

Al though macroscopi ca l ly no l es i ons may be v i s i b l e at the test s i te , i t

must b e empha s i zed that atop i c dermat i t i s i s often a genera l i zed s k i n

d i sease i n wh i ch a l so i n apparently norma l s k i n subcl i n i ca l a l terati ons

of the barr i er capaci ty may ex i st (de Jong h , 1981 ) .

86

A more severe react i on on the exposure to the surfactants as determ i ned

by water vapour l os s mea surements i n the s ubgroup of i rr i tant contact

dermati t i s as a who l e was not seen , a l though i t has been s tated that

genet i c factors may pl ay a rol e ( Kl i gman & Wood i ng , 1967 ) .

Th i s may be exp l a i ned as fol l ows :

1 ) I n th i s study , on ly one exposure of the s k i n to the tes t sub stance

was emp l oyed . After a cumu l at i ve i nsu l t to the s k i n by the same sur­

factant by means of a seri es of exposures , a pred i s pos i t i on for chro­

n i c i rr i tant contact dermati t i s may become man i fest .

2 ) W i th i n the et io l ogy of eczema a l l ergi c , i rr i tant and const i tuti onal

factors may p l ay a rol e . The rel at ive importance of these factors i n

each person i s often d i ffi cu l t to eva l uate . The present d i agnost i c

cr i ter i a may be too i naccurate to demonstrate ( smal l ) d i fferences i n

react i on on a cons t i tu t i onal bas i s between s ubj ects w i th and wi thout

a pred i s pos i t i on for chron i c i rr i tant contact dermati t i s .

3 ) The i nf luence of a cons t i tut i onal pred i s pos i t i on may be i ns i g n i fi cant

in compari son wi th the rel evant externa l i nfl uences ; the effects of

the l atter may overr i de cons t i tu t i ona l factors ( Ma l ten & Th i e l e ,

1973b ) .

4 ) The rol e of barr i er funct i on i mpa i rment i n the devel opment of i rr i ­

tant contact dermati ti s may be overemphas i zed ; consequentl y , d i ffe­

rences i n s u s cepti b i l i ty to barri er functi on d i sturbances may not

run para l l e l to d i fferences i n vu l nerabi l i ty to devel op chron i c i rr i ­

tant contact dermati ti s ( v . d . Val k et a l . , 1 984b ) .

87

TABL E I MEAN SK IN WATER VAPOUR LOSS VALUES (g/m2 h ) FOR ALL TESTED SUBJECTS , H EALTHY CONTROLS AND PATI ENTS

WITH ATOP I C DERMATIT I S AND I RR ITANT CONTACT DERMAT I T I S AFTER EXPOSURE TO THE SURFACTANTS

SURFACTANT ALL SUBJECTS H EALTHY CONTROLS I RR ITANT CONT . DERM . ATO P I C DERM .

( n = 103 ) ( n = 19 ) ( n = 1 7 ) ( n = 1 0 ) ± S . D . :!: S . D . :t S . D . + :!: S . D . s i gn . mean mean mean s i gn . mean

sod i um l aurate 9 . 5 : 3 . 2 9 . 5 : 3 . 3 10 . 5 : 3 . 6 0 . 442 1 1 . 3 +

2 . 8 0 . 1 71 -

sod i um stearate 10 . 4 : 6 . 1 9 . 5 : 3 . 6 9 . 7 : 2 . 7 0 . 940 1 1 . 6 + 4 . 0 0 . 197

sod i um l auryl su l fate 1 9 . 6 : 7 . 8 17 . 7 : 5 . 4 20 . 5 : 0 . 1 0 . 273 25 . 2 : 10 . 8 0 . 020

pota s s i um soap 1 1 . 1 : 3 . 7 10 . 6 : 3 . 7 1 1 . 8 : 4 . 4 0 . 394 1 1 . 8 + 2 . 9 0 . 377

cocobeta i ne 14 . 2 : 6 . 8 1 3 . 2 : 4 . 7 1 3 . 9 : 4 . 1 0 . 624 20 . 5 : 10 . 1 0 . 013 : 5 . 0 : 2 . 7 : 2 . 7 + 00

ceteareth - 1 2 1 0 . 4 9 . 0 10 . 5 0 . 1 1 2 16 . 2 9 . 8 0 . 007 00

cocami dopropyl beta i ne 1 0 . 8 : 4 . 5 10 . 0 : 2 . 8 10 . 6 : 4 . 4 0 . 640 1 7 . 0 + 7 . 4 0 . 001 -

pol ysorbate-60 9 . 0 : 4 . 0 8 . 4 ± 2 . 4 8 . 3 ± 1 . 9 0 . 853 14 . 6 + 9 . 7 0 . 016

d i st i l l ed wa ter 9 . 8 : 3 . 3 8 . 5 ± 2 . 5 9 . 8 : 2 . 4 0 . 1 3 5 14 . 1 :!: 6 . 1 0 . 002

contro l s++ 6 . 6 : 1 . 8 6 . 5 : 1 . 5 6 . 4 : 1 . 6 0 . 82 2 8 . 7 +

2 . 0 0 . 004 -

+ ) t-tests between the mean va l ues of correspond i ng test s i te s of pati ents w i th i rr i tant contact dermati t i s

and atopi c derma ti t i s and hea l thy control s o n the bas i s of pool ed vari ance .

++ ) the mean water vapour l os s of unexposed control s i tes .

References

1 ) Baker , H . , Kl i gman , A . M . Measu rement of tran sepiderma l water l oss by

el ectri cal hygrometry . Archi ves of Dermatol ogy 96 : 441-452 ( 1967 ) .

2 ) Bett l ey , F . R . The i rri tant effect of deterge nts . Transact i ons of the

St . John ' s Hos p i ta l of Dermatol og i ca l Soci ety 58 : 65-74 ( 197 2 ) .

3 ) Dyer , D . W . , Hassap i s , T . Compari son of detergent based versus soap

based l i qu i d soaps . Soap/Cosmeti cs/ Chem i ca l s peci a l i t i es 59 : 36-40

( 1 983 ) .

4 ) Fregert , S . Manua l of contact dermati ti s . Mu nksgaard , Copenhagen ,

pp 9- 10 ( 1981 ) .

5 ) Frosch , P . J . , Kl i gman , A . M . The soap chamber tes t . Journa l of the

Ameri can Academy of Dermatol ogy 1 : 35-41 ( 1979 ) .

6 ) Frosch , P . J . Pri nci p l es of Cosmeti cs for the Dermatol ogi s t . Fros t , P .

( ed . ) St . Horwi tz , Mosby , St . Loui s , pp 5 - 1 2 ( 1982 ) .

7 ) G i g l i , I . , Baer , K . L . Dermatol ogy i n Genera l Med i c i n e . McGraw-Hi l l

Book Company , New York , pp 520- 528 ( 1979 ) .

8 ) Has s i ng , J . H . , Nater , J . P . , B l eum i n k , E . The i rri tancy of l ow concen­

trati ons of soap and synthet i c detergents as measured by s k i n vapour

l os s . Dermatol og i ca 164 : 314-321 ( 1982 ) .

9 ) Hu l l , H . , N i e , N . H . Stati st i ca l Pac kage for the Soc i a l Sci ences .

Update 7-9 . McGraw-Hi l l Book Company , New Yor k , pp 1-79 ( 1981 ) .

1 0 ) De J ongh , G . J . Poros i ty of human s k i n i n v i vo assessed v i a H2o l oss ,

co2 l os s and e l ectr i ca l i mpedance of hea l thy vol unteers , atop i c and

psori ati c pati en ts . Curr . Probl . Derm . Karger , Basel 9 : 83-101 ( 1981 ) .

1 1 ) Van Ketel , W . G . , Bruynzee l , A . P . , Bezemer , P . O . , Stamhu i s , J . H .

Tox i c i ty of handcl eaners 168 : 94-99 ( 1984 )

1 2 ) Von Ki ss , G . Prufung von durch Was chmi ttel bed i ngten Hautschad i gun­

gen . Dermatosen i n Beruf und Umwe l t 29 : 1 5 - 18 ( 1981 ) .

1 3 ) Kl i gman , A . M . , Wood i ng , W . M . A method for the measu remen t and eva l u­

at ion of i rr i tants on human s k i n . Journa l of I nves t i gat ive Dermato l o ­

g y 49 : 78-94 ( 1 967 ) .

1 4 ) Kooyman , D . J . , Snyder , F . H . Tests for mi l dness of soa p . Archi ves of

Dermatol ogy & Syphi l o l ogy 46 : 846-855 ( 1942 ) .

1 5 ) Mal ten , K . E . , T h i el e , F . A . J . Eva l uat ion of s k i n damage . I I Water

89

l os s and carbon d i ox i de re l ease measurements rel ated to s k i n res i s ­

tance measurements . Bri ti s h Journ a l o f Dermatol ogy 89 : 565- 569

( 1 973a ) .

1 6 ) Mal ten , K . E . , Th ie l e , F . A . J . Some theoret i ca l a spects of ' orthoerg i c '

( = i rri tant ) dermati ti s . Arch i ves Be l ges de Dermatol ogi e et de Syphi ­

l i graph i e 28 : 9-22 ( 1973b ) .

17 ) Ma l ten , K . E . Thoughts on i rri tant contact derma t i ti s . Contact Derma ­

t i t i s 7 : 238-247 ( 1981 ) .

18 ) Nater , J . P . , de Groot , A . C . Unwanted effects of cosmeti cs and drugs

used in dermatol ogy . Excerpta Med i ca , Amsterdam , Oxford , pp 1 -28

( 1983 ) .

1 9 ) N i l sson , G . E . Measurement of water exchange through s ki n . Med i c a l &

B i o l og i ca l Eng i neeri ng & Comput i ng 1 5 : 209-218 ( 1977 ) .

20 ) Pol ano , M . K . The i nteraction of detergents and the human s k i n . Jour­

na l of the Soci ety of Cosmeti c Chemi sts 19 : 3-20 ( 1968 ) .

2 1 ) P i r i l a , V . Chamber test versus patch test for epi cutaneous tes t i ng .

Contact Derma t i t i s 1 : 48- 52 ( 1975 ) .

2 2 ) Smeen k , G . The i nfl uence of detergents on the sk i n . Archi v fUr k l i ­

n i sche und experi mentel l e Dermatol ogi e 235 : 180- 191 ( 1969 ) .

2 3 ) Th ie l e , F . A . J . , Ma l ten , K . E . Eva l uati on of s k i n damage . I . S k i n re­

s i stance measurements wi th a l ternati ng current ( i mpedance meas ure­

ments ) . Bri t i sh Journa l of Dermatol ogy 89 : 373-382 ( 1 973 ) .

24 ) Van der Va l k , P . G . M . , Nater , J . P . , B l eumi n k , E . S k i n i rri tancy of

surfactants as asses sed by water vapour l os s measurements . Journal

of I nvesti gati ve Dermatol ogy 82 : 291-293 ( 1984a ) .

25 ) Van der Val k , P . G . M . , Nater , J . P . , B l eumi n k , E . The i nfl uence of

repeated s k i n exposures to surface acti ve agents on water barr i er

and morpho l og i c parameters . Submi tted for publ i cat ion : Journa l of

Dermatol og i ca l Research ( 1 984b ) .

26 ) Ummenhofer , B . Hornschi chtphys i o l og i sche Grundl agen der Praventi on

und Rehab i l i tati on von Berufsekzemen . Dermatosen i n Beruf und Umwe l t

29 : 102-106 ( 1 981 ) .

90

CHAPTER 4

THE I NFLUENCE OF REPEATED S KI N EXPOSURES TO SURFACE ACT I VE

AGENTS ON WATER BARRI ER AND MORPHOLOG I C PARAMETERS

Submi tted for publ i cat ion i n

Journal of Dermato l og i cal Research

91

Authors :

P . G . M . van der Va l k

J . P . Nater

E . B l eum i n k

Summa ry

Surface act ive agents may i mpa i r the barr i er of the horny l ayer and may

a l so have a tox i c effect on the vi ab l e l ayers of the epi dermi s and der­

mi s .

These effects of surfactants may contri bute to the devel opment of i rr i ­

tant contact dermati ti s , especi a l l y i f the s k i n i s frequentl y exposed .

Data on repeated exposure of the s k i n to s u rfactants , however , a re scarce.

In th i s s tudy , the effect of repeated exposure to l ow concentrat i ons of

surfactants on the barrier fu nction of the s k i n for water a nd on the

c l i n i ca l appearance of the s k i n ( soap effect ) was eva l uated .

For th i s purpose , the s k i n of the forearms of a panel of 20 heal thy med i ­

cal students was exposed three t i mes to fou r pure surfactants ( 0 . 5 w/ v% )

and to four propri etary products ( 1 w/ v% ) a t the same test s i te for

peri ods of 24 hours .

The effects of the test substances proved to be cumu l ati v e , except for

sod i um l aurate and pol ysorbate-60 , wh i ch had hard l y any effec t .

The general pa ttern of water barri er funct ion a nd macroscop i ca l l y v i s i b l e

changes corresponded , a l though d i fferences were observed .

Repeated expos ure to l ow concentrati ons of s urfactants may l ead to cumu­

l a t i ve impa i rment of the barri er functi on of the horny l ayer and conse­

quently to i ncreased permeat ion of substances . Th i s i ncreased permeati on

may be an important factor i n the devel opment of i rri tant contact derma­

t i t i s , a l though other factors may a l so pl ay a ro l e .

I ntroducti on

Surface acti ve agents are known to l ead to impa i rment of the barr i er ca­

paci ty of the s tratum corneum and a l so to d amage to the vi ab l e l ayers of

the epi dermi s and dermi s ( 1 , 4 , 1 8 ) .

Under l abora tory condi t i ons , i t has been shown that a s i ng l e exposure of

the s k i n to l ow concentrati ons of a surfactant as present i n c l eans i ng

mater i a l s may l ead to changes i n barr i er funct i on ( 2 , 6 , 19 ) .

A l though as a ru l e no marked i nf l ammatory reacti ons are observed after a

s i ng l e app l i cat i on of l ow concentrati ons of a surfactant , macroscopi ca l l y

92

vi s i b l e effects ( erythema , sca l i ng ) have been found to occu r ; a c l ear

associ ati on wa s found between macroscopi ca l l y v i s i b l e effects and s k i n

water vapou r l os s changes ( 20 ) .

At present , data on the effect of repeated or cont i nuous exposure to l ow

concentrat i ons of surfactants are s carce , j us t as those on the summa­

t i on effect a nd pos s i b l e i rrevers i bl e changes whi ch may occur after

repeated exposure to surfactants ( 5 , 7 ) .

To eva l uate the rol e of surfactants i n the deve l opment of chroni c i rr i ­

tant contact derma t i ti s , control l ed stud i es on t h e accumu l at i on effects

of repeated exposure to surfactants may be of i mportance .

The a im of t h i s study was to i nvest i gate the effect of repeated exposures

to surfactants on water barr i er funct i on and on the c l i n i c a l appearance

of the s k i n . For th i s purpose , the s k i n of the forearms of a panel of

heal thy vo l unteers was exposed three t imes to four propri etary c l ea ns i ng

products a nd four surfactants duri ng peri ods of 24 hours .

The barr i er functi o n of the s k i n was eva l uated by means of s k i n water va­

pour l os s measurements ( 12 , 20 ) . The morphol og i c changes of the s k i n were

graded accord i ng to a " v i sua l scori ng system" ( 4 ) .

Mater i a l s and methods

The s k i n of the vol ar s i de of the forearms was u sed for the exposures to

the test substances . Each substance was appl i ed to the s ame s k i n s i te

three t imes for per i od s of 24 hours ( on Monday , Tuesday a nd Wednesday of

the f irst week of the i nvest i gat ions ; see schedu l e ) .

The s k i n of both arms was exposed to the fol l owi ng propri etary products

a nd surfactants :

R ight arm : Left arm:

Type of

Brand name pH Chemi ca l name surfactant pH

Zwi t s a l baby soap 10 . 6 Cocobetai ne amphoter i c 5 . 2

Su l foderm soap 5 . 9 Sod i um l aurate a n i on i c 9 . 3

Neutrogena soap 9 . 8 Sod i um l auryl s u l fate a n i o n i c 7 . 3

Lactacyd soap 3 . 8 Polysorbate-60 non i on i c 3 . 8

93

For the exposures , a l um i n ium chambers ( La rge F i n n Chambers , Epi test Ltd .

Oy Hel s i nk i , F i n l and ) wi th a d i ameter of 12 mm were used . Each chamber

was fi tted wi th 5 pi eces of absorbi ng paper ( Whatman ) wh i ch were satura­

ted with 100 � l of the test substance . The propri etary products were

tested i n a 1 w/v% sol uti on and the surfactants i n a 0 . 5 w/v� s o l u t i on .

Unexposed occl uded ( by an empty chambe r ) s k i n served a s a control area .

The effect of the test substances on the s k i n was eva l uated after each

24 hour exposure ( on Tuesday , Wednesday and Thursday of the fi rst week

of the i nvest i ga t i o n ) and subsequently on Fri day of the same week and on

Monday to Thursday of the second week ( see schedu l e ) .

The durat ion of th i s study had to be l im i ted to th i s peri od for pract ica l

reascns .

Fi rst week Second week 3: --i :E: --i "Ti (./') (./') 3: --i :E: --i 0 <: ro ::::r ""'l Qj <: 0 <: ro ::::r ::> ro a. <: �. <+ ::> ::> ro a. <: a. Ul ::> -s a. <: a. a. Ul ::> -s Qj a. ro VI Qj -s Qj Qj a. ro VI

'< Qj VI a. '< a. '< '< Qj VI a. '< a. Qj Qj '< a. Qj

Qj '< '< Qj '< '< '<

" " " " " I " " " I A I I : I : I I I I I

Schedu l e of the app l i cat i on a nd eva l ua t i on of the test subs tances .

- - --> appl i cat i o n , --> eva l uat i o n .

The tests were performed i n a panel o f hea l thy med i ca l s tudents wi thout

s k i n cond i t i ons ( 1 1 women and 9 men rang i ng in age from 19 to 34 years ) .

The s k i n water vapour l oss of the exposed s k i n s i tes and control s i tes

was measured by means of an Evapori meter ( Servo Med , Stockho lm , Va l l i ng­

by , Sweden ) . The pri nc i p l e of th i s i nstrument is based on the cal cul at ion

of the vapour pressure gradi ent adj acent to the s k i n surface . I n the

steady state , the vapour pressure grad i ent i s proporti on a l to the amount

of water evaporated per uni t t ime and s k i n s u rface wi t h i n a boundary

l ayer surround i ng the s k i n . The actual gradi ent and thereby the evapora­

t i on rate i s ca l cul ated from the s i gn a l s of two pa i rs each of a humi d i ty

transducer a nd a thermi stor l ocated at two d i fferent d i stances i n a

measuri ng probe . The d i ameter of the measured s k i n corresponds w ith that

of the exposed s k i n area ( 12 mm ) ( 12 ) .

94

Dur i ng the measurement , the room temperature was kept a l most constant at

20oc . Rel at i v e humi d i ty vari ed from 2 1-36% ( 28 . g � 5 . 2% ) .

The macroscop i ca l l y v i s i bl e changes i n the s k i n after the exposures were

b l i nd ly eval uated by an i ndependent i nvesti gator u s i ng the " v i su a l sco­

r i ng sys tem" as descri bed by Frosch & Kl i gman ( 1 979 ) ( 4 ) :

Erythema : 1+ s l i g ht rednes s , spotty or d i ffuse

2+ moderate , un i form redness

3+ i ntense redness

4+ fi ery red wi th erythema

Scal i ng : 1+ f i ne

2+ moderate

3+ severe w ith l arge fl a kes

F i ssures : 1+ f i ne cracks

2+ s i ng l e or mul t i p l e broader f i s sures

3+ wide cra c ks wi th hemorrhage or exudat i on .

Stat i st i ca l methods

The d i fference i n s k i n wa ter vapour l oss between the exposed and the con­

trol s i tes as wel l as the di fference in s k i n water vapour l os s after one

and after three exposures ( both i ndependent data ) was tested for s i g n i f i ­

cance us i ng a t- test for pai red observati ons ( 1 1 ) .

Resu l ts

The effects of the test substances on the s k i n are presented by graphs of

s k i n wa ter vapou r l os s and morpho l og i c changes i n the sk i n versus the

t ime course ( Fi g I a nd Fig I I ) . The overa l l mean s core of the test panel

duri ng 8 measurement sess i ons for the unexposed s k i n ( i ndi cated i n the

graphs ) was 2 . 8 g/m2h � 1 . 3 . For a l l the test substances , except for so­

d i um l aurate , water vapour l os s cumu l at i ve ly i ncreased on repeated ex­

posure ( s i g n i fi cance of the i ncrease in water vapour l os s after one and

three exposures , p < 0 . 01 ) .

95

For sod i um l aurate , thi s i ncrease was l ess pronounced ( p < 0 . 2 ) . After

the exposures repa i r of barr i er functi on for water was observed for the

s k i n exposed to the test subs ta nces ( s i gn i fi cance of the decrea se in wa­

ter vapour l oss after the ex pos ures and the l as t measu rement ses s i on for

the d i fferent test substa nces , 0 . 07 < p < 0 . 001 ) . Thi s repa i r , however ,

was not compl ete at the l ast day of the i nvesti gation ( s i gn i fi cance of

the d i fference between the test substances and the control measu rement ,

0 . 02 < p < 0 . 001 ) .

The modest v i s i bl e a l terati ons after one exposure i ncreased after the

second and th i rd exposures , a l though the propri etary produc t , Neutrogena

and the surfactants , polysorbate-60 and sod i um l aurate el i c i ted hard l y

any v i s i b l e effects . Erythema , as caused by t h e tes t substances , de­

creased i n the course of t ime . I n the cas e of the more severe a l tera­

tions erythema was s ti l l present on the l ast day of the i nvesti gati on .

The s l ow decrease i n the v i s i b l e changes was partly due to the more pro­

nounced chappi ng ( s l i ght fi ssuri ng ) and scal i ng i n some subj ects after a

few days after the l ast exposure . The general pattern of water barri er

functi on d i sturbances and the pattern of the macroscopi ca l l y v i s i b l e

changes i n the cou rse of t ime corres ponded .

D i scu s s i on

The data presented i n th i s communi cati on c l earl y s how that repeated ap­

pl i ca t i on of l ow concentrati ons of surface active substances may l ead to

a marked impa i rment of the stratum corneum barri er ca paci ty for water

vapour l os s . The effects of the tox i c pri nci p l es appear to be cumu l a t i ve

wi th regard to water vapou r l oss . Genera l l y , th i s barr i er functi o n im­

pai rment para l l el ed the deve l o pment of v i s i b l e impa i rment of the s k i n .

Cumu l at ive barri er funct ion impa i rment has been i ncrimi nated for i ts rol e

i n the devel opment of chroni c i rri tant contact dermat i ti s . The resu l ts of

th i s study su pport th i s v i ew , a l though the data must be i nterpreted with

some care . I t has been shown that conti nuous exposu re even to s trong i r­

ri tant stimu l i wi l l as a ru l e l ead to epiderma l hyperp l a s i a and , a l though

an i ncreased permeation through th i s th i c kened s k i n has been demons trated

( 10 , 13 ) , an i ncrease of water l oss cou l d not be demons trated by us ( 17 ) .

96

Thu s , i t seems pl au s i b l e that the epi derm i s repeated l y exposed to i rr i ­

tant st imul i may adapt structura l l y a nd perhaps metabol i ca l l y ( 10 , 13 ) .

Externa l i nj u ri ous effects may impa i r the barr i er fu nction of the s tra­

tum corneum a nd may i nterfere wi th norma l homeo s tas i s of the epi derm i s

a n d dermi s ( 9 , 1 3 , 16 , 18 ) . These effects are most ly revers i b l e and on ly

i n except i onal cases wi l l changes l ead to a d i m i n i shed repa i r ca pac i ty

wh i ch may u l timately l ead to a chron i ca l l y d i seased s k i n occur ( 9 , 16 ) .

S k i n barri er impa i rment by repeated exposures to i rri tant stimul i l i ke ,

e . g . , c l eans i ng mater i a l s { the da i l y wear and tear of the s k i n ) i s proba­

bly an important factor i n the devel opmen t of chron i c i rr i tant contact

derma t i ti s . It seems j ust i f iab l e , however , to a ssume that other factors

may be i nvol ved i n the pathogenes i s { 13 ) .

Faul ty i nfl ammatory control mecha ni sms , d i s turbance of homeostas i s i n

the v i ab l e l ayers of the epi derm i s a nd derm i s and accumu l ati on of i rr i ­

tant subs tances o r ( endogeneou s ) ant i gens i n repeatedl y exposed s k i n

s i tes may a l so b e cons i dered as causa t i v e o r contri buti ve factors i n

the devel opment of i rrevers i b l e changes i n the s k i n u l t imatel y l eadi ng

to chron i c i rr i tant conta ct derma t i t i s ( 3 , 8 , 9 , 14 , 1 5 , 21 ) .

97

w

9

8

7

6

5 � � � 4

� � 3 0 � � > 2 c � � 1

Fi g . I A .

2 3 5 6 days

7 8 9 1 0 1 1

Mean water vapour l os s ( 20 subj ects ) of the sk i n after repeated

exposures to the propri etary products versus t ime ( g/m2h ) .

e--e Lactacyd soap 7 . 5 g/m2h ! 3 . gt

l--A Su l foderm soap 7 . 4 gjm2h ! 2 . 9

0--0 Neutrogena 4 . 0 g/m2h ! 2 . 1

&--� Zwi tsa l babysoap 7 . 0 g;m2h ! 3 . 9

* + Mean water vapour l oss - S . D . after three exposures

98

10

9

8

7

6

5 "' "' 0 I, .... � 3 0 c.. "' > c 2 :;;: "'

F i g . I B .

..--:----

2 3 I, 5 6 days

7 8 9 10 11

Mean water vapour l os s ( 20 subj ects ) of the s k i n after repeated

s k i n exposures to the s k i n su rface active su bstances versus t ime

{ g/m2h ) .

.___. pol ysorbate-50 2 3 . 3 g/m h ± 1 . 3* !-! sod i um l au rate 4. 6 g/m2h ± 1 . 7

()--{) sodi um l aury l su l fate 8 . 9 g/m2h ± 4 . 3 6--6. cocobetai ne 7 . 4 g/m2h + 2 . 5

* Mean water vapour l os s ± S . D . after three exposures

99

"' Cll 0'1

2.5

2,0

� 1 ,5 .r;; u

u

·g. 1 .0 0 .r;; 0.

� 0.5

Fi g . I I A .

d a y s

Mean scores of morph o l og i c changes ( 20 subj ects ) in the s k i n

after repeated exposures t o the propri etary products .

.-e Lactacyd

!-! Sul foderm

o--o Neutrogena

�--� Zwi tsal babysoap

100

"' CIJ Ol

2 .5

2 .0

:;; 1 .5 .r. u

u

� 1 .0 0

.r. a. ..

� 0.5

F i g . l i B .

2 3 5 6 7 8 9 1 0 1 1 days

Mean scores of morphol og i c changes ( 20 subj ects ) i n the s k i n

after reneated exposures t o surface acti ve substances versus

t i me .

e--e polysorbate-60

!--! sod i um l aurate

o--o sod i um l auryl su l fate

�� cocobeta i ne

101

References

1 ) Bett l ey , F . R . Some effects of soap on the s ki n . B r . Med . J . 1 :

35-41 ( 1 960 ) .

2 ) Bettl ey , F . R . The i rri tant effects of detergents . Trans . St . J ohn ' s

Hos pi ta l Oermatol . Soc . 58 : 65-74 ( 1 972 ) .

3 ) Bonta , I . L . Endogeneous modul ators of the i nfl amma tory response .

I n : I nfl amma t i on , pp 523-567 ( 1 978 ) Edi tors : Vane & Ferre i ra .

Spri nger-Verl ag , Berl i n .

4 ) Fro sch , P . J . , Kl i gman , A . M . The soap chamber tes t . J . Am . Acad .

Oermatol . 1 : 35-41 ( 1979 ) .

5 ) Frosch , P . J . I rri tancy of soaps a nd detergent bars . I n : Pri nc i p l es

of cosmetics for the dermato l og i s t , pp 5 - 1 2 ( 1982 ) Edi tors : Frosch

& Horwi tz . Mosby , St. Loui s .

6 ) Hass i ng , J . H . , Nater , J . P . , B l eumi n k , E . The i rri tancy of l ow con­

centrati ons of soap and synthet ic detergents as measured by s k i n

wa ter l oss . Oermato l og i ca 1 6 4 : 314-321 ( 1 982 ) .

7 ) Von Ki s s , G . ( 1 981 ) Prufung von durch Waschmi ttel bed i ngten Haut­

schad i gunge n . Derm . Beruf Umwel t 29: 1 5 - 1 8 ( 198 1 ) .

8 ) Ma l k i n son , F . O . , Fergu5o n , E . H . Percutaneous absorpti on of hyd ro­

corti sone-4-c 14 i n two human subjects . J . I nves t . Derm . 2 5 : 281-

283 ( 1 955 ) .

9 ) Mal ten , K . E . Thoughts on i rri tant contact dermati ti s . Contact Derma ­

ti t i s 7 : 238-247 ( 1981 ) .

10 ) McOs ker , D . E . , Beck , L . W . Characteri sti cs of accomoda ted ( hardened }

s k i n . J . I nves t . Dermato l . 48 : 372-383 ( 1967 ) .

1 1 ) N i e , N . H . , Had l a i Hul l , C . , Jenk i ns , J . G . , Stei nbrenner , K . , Bent ,

D . H . Stati sti ca l Package of the Soci a l Sci ences , pp 249-275 ( 1981 )

McGraw- Hi l l Book Company , New York .

1 2 } N i l sson , G . E . Measu rements of water exchange through s k i n . Med . &

B i o l . Eng . & Comput . 1 5 : 209-2 15 ( 1 977 ) .

1 3 ) Prottey , C . The mol ec u l a r bas i s of sk i n i rri tat i o n . I n : Cosmeti c

Sci ence , Vol 1 , pp 2 75- 349 ( 1978) Ed i to r : Breuer . Academi c Press ,

London .

1 4 ) Schaefer , H . , Zesch , A . , Stuttgen , G . Sk i n permeab1 l i ty : Keservo 1 r

102

function of the horny l ayer . I n : Handbuch der Haut- und Geschl echts­

krankhe i ten . Norma l e und Patho l og i sche Phys i o l ogy der Haut , pp

601-604 ( 1981 ) Ed i tor : Jadassohn . Spri nger-Verl ag , Berl i n .

1 5 ) Turk , J . L . , Wi l l oughby , D . A . Immuno l ogi ca l and para immunol ogi cal

as pects of i nfl ammati on . I n : I nfl amma t i on , pp 523- 567 ( 1978 ) Ed i ­

tors : Vane & Ferrei ra . Spri nger-Ver l ag , Berl i n .

1 6 ) Ummenhofe r , B . Hornsch i chtphys i o l og i sche Gru nd l agen der Pravention

und Rehabi l i ta t i on von Berufsekzemen . Derm . Beruf Umwel t 29 : 102-

106 ( 1981 ) .

1 7 ) Unpub l i shed data .

1 8 ) Van der Val k , P . G . M . , Kru i s -de Vri es , M . H . , Nater , J . P . , B l eumi nk ,

E . , de Jong , M . C . J . M . Eczematous ( i rri tant a nd a l l ergi c ) reacti ons

of the s k i n and barri er functi on a s determi ned by water vapour l os s .

Accepted for publ i cat ion : C l i n . & Exp . Derm .

1 9 ) Van der Val k , P . G . M . , C r i jns , M . C . , Nate r , J . P . , Bl eumi nk , E .

Sk i n i rr i tancy of commerc i a l l y avai l ab l e soap a nd detergent bars as

measured by water vapour l os s . Derm . Beruf Umwel t 3 : 87-90 ( 1984 ) .

20 ) Van der Va l k , P . G . M . , Nater , J . P . , B l eumi nk , E . S k i n i rri tancy of

surfactants as as sessed by water vapour l oss measurements . J . I nvest .

Dermato l . 82 : 291-293 ( 1984 ) .

2 1 ) V i ckers , C . F . H . Exi s tence of reservo i r i n the s tratum corneum . Arch .

Dermato l . 88 : 20-23 ( 1963 ) .

103

CHAPTER 5

ECZEMATOUS ( I RRITANT AND ALLERG I C ) REACT IONS OF THE SKIN AND

BARR I ER FUNCT ION AS DETERMI NED BY WATER VAPOUR LOSS

Accepted for publ i cati on i n

Authors :

P . G . M . van der Va l k

M . H . Kru i s-de Vri es

J . P . Nater

E . B l eum i n k

M . C . J . M . de Jong

C l i n i ca l and Experimental Dermatol ogy

1 04

Summary .

The a im o f th i s study was t o compare t h e i nfl uence of i rri tant a n d a l l er­

g i c react i ons on the barr i er fu nction of the s k i n and to correlate d i s ­

turbances o f barr i er funct i on wi th macroscop i ca l l y v i s i bl e changes .

For th i s purpose , the s k i n of the vol ar s i de of the forearm was exposed

to n i ckel su l fate {5% ) , sod i um l aury l s u l fate ( 5% ) , d i methyl su l fox i de

{50• ) and phenol su l fate (5% ) duri ng a peri od of 48 hours . D i s ti l l ed

water served as contro l .

The exposures were made i n a test panel of 23 fema l e subj ects cons i st i ng

of a grou p of 14 pati ents w i th pos i ti v e s k i n react i ons to n i ckel su l fate

and 9 contro l s i n whom no ev idence of s k i n d i sease was found .

Both s k i n water vapour l oss measu rements and a '' v i sua l scori ng system"

{ based on erythema , f i s su r i ng and scal i ng ) were used to assess the effects

of the substances on the s k i n . The test s i tes ex posed to n i c kel s u l fate

were a l s o read for a l l erg i c react i ons .

Al l test substances caused an i ncrease i n s k i n water vapour l os s i n com­

pari son with d i s ti l l ed water i n both groups . The i ncrease was found to be

stat i sti ca l l y s i g n i f i cant for n i c kel s u l fate , sod i um l auryl su l fate and

d imethyl s u l fox i de {a = 0 . 05 ) . Erythema was cons i stent l y el i c i ted by the test substances , parti cu l arly

by sod i um l auryl su l fate . In add i t i on , d i methyl su l fox i de reg u l ar ly

caused f i ne cracks ( chappi ng ) .

The corre l at i on between erythema and the i ncrease i n water vapour l os s

after exposure o f the s k i n t o an i rri tant var i ed cons i derably from sub­

stance to substance and was poor for n i ckel su l fate {5% ) and phenol ( 5% ) and negati v e for d i methyl s u l fox i de (50% ) . A s i g n i fi cant correl at ion was

found for sodi um l auryl s u l fate ( 5% ) . Th i s impl i es that a l i near re­

l at ions h i p between barrier funct ion d i sturbance and damage to the v i ab l e

cel l s o f deeper l ayers o f the s k i n may not b e as sumed beforehand .

Water vapour l os s measurements i n s k i n exposed to n i c ke l s u l fate revea l ed

that severe a l l erg i c s k i n reacti ons ( 3+ and 4+ reacti ons ) may l ead to an

i ncrease i n water v apour l os s i n compari son wi th d i sti l l ed water .

Al l erg i c s k i n react i on may a l so i nf l uence adj acent i rri tant react i on s :

The i rr i tant effect of sod i um l auryl su l fate was i nf l uenced by a pos i t i ve

105

patch test reacti on to n i ckel s u l fate .

I ntroduc t i on .

Substances wh i ch are desti ned to contact the s k i n must be eva l uated for

unwanted effect s . Var i ou s methods have been devel oped for th i s safety

eva l uat i on . Mos t of these ut i l i ze parameters for asses s i ng i nfl ammatory

react i ons ei ther quanti tat i ve ly by measu ri ng , for examp l e , s k i n fo l d

t h i ckness ( oedema ) ( Wah l berg , 1983 ) and cutaneous bl ood f l ow ( Laser

Doppl er fl owmetry ) ( N i l sson , Otto & Wah l berg , 1982 ) or sem i quant i tat i ve­

ly by , for examp l e , " v i su a l scor i ng " of erythema , scal i ng and f i ssuri ng

( B ettl ey , 1964 ; Kl i gman & Wood i ng , 1967 ; Frosch & Kl i gman , 1979a ; Da h l &

Tranci k , 1977 ) .

Most m i l d i rri tants encountered i n da i l y l i fe do not provoke v i s i b l e

changes i n the s k i n (Ma l ten , 1981 ) . These i rr i tants , however , may have

a subcl i n i ca l effect wh i ch may be cumu l at i v e and wh i ch may in the l ong

run l ead to the devel opment of chron i c i rr i tant contact dermat i t i s .

Because of th i s , methods for assess i ng subc l i n i ca l effects of i rr i tants

have been devel oped ( Smeen k , 1968 ; Bj ornberg , 1968; Mal ten & den Arend ,

1978 ; von Ki s s , 1979 ; He i s e , von Mattheus & Brust , 1983 ) .

Among such techn i ques , s k i n water vapour l oss measu rements proved to be

usefu l in assess i ng the i nfl uence of substa nces on the barr i er funct i on

i ntegri ty (Mal ten & T h i e l e , 1973a , 1973b ) . These measurements are based

on the assumpt i on that the i ncrease i n water vapour l os s para l l e l s the

extent of barri er funct i on d i sturbances (de Jongh , 1981 ) .

The a im of the study reported here was to assess the i nfl uence of i rr i ­

tant and a l l erg i c react i ons o n t h e barri er funct i on to a macroscop i ca l l y

v i s i b l e chang e .

T h e i nvest i g at i on was performed o n a test panel cons i st i ng o f a group of

14 fema l es wi t h pos i t i v e patch test reacti ons to n i ckel s u l fate and a

grou p of 9 fema l e subj ects without a ny known a l l ergy .

106

Mater i a l s and method s .

Unaffected s k i n of the vol ar s i d e o f t h e forearm was exposed to the

fol l owi ng su bstances :

1 ) n i ckel su l fate-7H20 5 g/v% i n d i s t i l 1 ed water , pH 5 . 4 .

2 ) sod i um l auryl s u l fate , 5 g/v% in d i s t i 1 1 ed water , pH 7 . 3 .

3 ) d imethyl su l fox i de 50 g/v% i n d i st i l l ed water , pH 7 . 1 .

4 ) phenol 5 g/v% i n d i st i l l ed water , pH 6 . 2

5 ) d i s t i l l ed water pH 6 . 5 .

The test substances were appl i ed to the sk i n for a peri od of 48 hours .

One- hundred mi crol i ters of the tes t substances were pi petted ( Capi ­

l etto r , C l i n i con AB , Stockho lm , Sweden ) i nto an a l um i n i um chamber of

12 mm d i ameter ( Large F i nn chamber , Epi test Ltd . Oy , Hel s i nki , F i n l a nd )

wh i ch conta i ned f i ve pi eces of a bsorb i ng paper ( Whatma n ) . The chambers

were sea l ed to the s k i n by means of adhes i v e tape ( Scanpor tape , Norges­

p l aster A/ S , Os l o , Norway ; F i xomu l l stretch , Bei ersdorf AG , Hamburg ,

Germany ) . After the 48 hours exposure , the morphol og i ca l changes of the

test s i tes were graded a s fol l ows ( Frosch & Kl i gman , 1 97 9b ) :

erythema :

sca l i ng :

f i s sur i ng :

1+ s l i ght rednes s , s potty or d i ffu s e .

2 + moderate rednes s .

3+ i ntense red ness .

4+ fi ery red wi th oedema .

1+ f i n e .

2 + moderate .

3+ severe wi th l arge fl a kes .

1+ f i ne cracks .

2+ s i ng l e or mu l t i p l e broader f i s �ures .

3+ wi de cracks wi th hemorrhage or exudat ion .

The test s i tes on the arm were a l so read for a l l erg i c react i ons accord i ng

to standards devel oped for patch tes t i ng a nd graded a s fol l ows ( Nater ,

197 4 ) :

107

0 no reacti on .

1+ erythema wi thout i nf i l trat ion .

2+ erythema wi th papu l es / i nfi l trat i on .

3+ erythema wi th ves i c l es .

4+ conf l uent ves i c l es .

Ski n water vapour l os s measurements on the tes ted s k i n s i tes were per­

formed after a wa i t i ng peri od of 15 mi nutes . The measurements were done

u nder neutra l envi ronmental c i rcumsta nces ( room temperature , 2 1 . 1 °C

± 1 . 1 ; re l at i ve humi d i ty , 38 . 1 k ± 9 . 0 ) .

The mea surements were made by means of an Evaporimeter ( Servo Med , Stock­

hol m , Va l l i ng by , Sweden ) accord i ng to methods descri bed i n deta i l earl i er

( N i l sson , 1977 ; van der Va l k , Na ter & Bl eum i nk, 1984 ) . The opera t i ng

pri nc i pl e of th i s i nstrument i s based on ca l cu l ati on of a water vapour

pres sure grad i ent perpend i cu l ar to the sk i n .

The exposures and measurements were performed i n two groups :

1 ) a grou p of 14 femal e pati ents (mean age , 27 . 9 � 1 0 . 2 ; range , 19-52 y . )

w ith a h i story of derma t i t i s ; a l l were i n a qu i et phase of the derma­

t i t i s . These pati ents were sel ected on the ba s i s of pri or pos i t i v e

patch t e s t resu l ts t o n i c kel su l fate and thei r react i on to n i c ke l

su l fate as appl i ed duri ng the i nvest igat i o n ;

2 ) a grou p o f 9 fema l e control s (mean age , 10 . 3 ; range , 19-52 y . ) wi thout

any known s k i n d i sease or a l l ergy .

Stat i st i ca l methods :

The d i fferences between the test chem i ca l s as regards the i r effects on

the barri er funct i on of the s k i n (mean s k i n vapour l oss scores ) were

tested for s i g n i f i cance as compared wi th d i st i l l ed water u s i ng a t -test

for pai red data . To study the associ at1 on between the morphol og i ca l

changes o f the s k i n and the s k i n water vapour l os s va l ues , rank order

corre l at i on coeffi c i ents were cal cu l ated ( Kenda l l ' s tau ) . Th i s stat i s t i ­

c a l method was sel ected because o f the l arge number o f t i ed ranks i n

the " v i sua l scor i ng " vari abl es ( N i e et a l . , 1981 ) .

108

Res u l ts .

The mean val ues for the s k i n water vapour l oss from the expos ed s k i n

s i tes are presented i n Tabl e I . Marked ly i ncreased va l ues were observed

for a l l test substances as compared wi th d i st i l l ed water . The di ffe­

rences were found to be stat i st i ca l ly s i g n i fi cant ( t-test for pai red

data ) for n i c kel su l fate ( 5% ) , sod i um l aury l s u l fate ( 5% ) and d i methyl

su l fox i de ( 50% ) {Tab l e I I ) . The observed d i fferences in reacti on between

the a l l erg i c i nd i v idua l s and control s were found to be s i gn i f i cant for

sod i um l auryl s u l fate.

The ari thmet i c means of the scores for erythema , f i s suri ng and scal i ng as

graded accord i ng to the " v i su a l scori ng system" are l i sted i n Tabl e I I I .

Erythema , espec i a l l y after exposure to sod i um l au ry l s u l fate , was con­

s i stently obs erved . D imethyl su l fox i de regu l ar l y el i c i ted fi ne cracks

( chappi ng ) . The assoc i at i on between erythema a nd water vapour l os s from

exposed s k i n was determi ned ( Kendal l ' s tau correl at i on coeffi c i ent ) .

A s i gn if i cant correl ati on was found for sod i um l au ryl s u l fate ( 5% ) .

Corre l a t i on was poor for n i ckel s u l fate ( 5% ) and phenol ( 5% ) and nega­

t i ve for di methyl s u l fox i de ( 50% ) . Sca l i ng and f i ssuri ng were too un­

common to just i fy ca l cu l at i on of correl at i on coeffi c i ents w ith s k i n

vapour l os s {Tabl e I I I and I V ) .

Grou ps w ith the same grade of a l l erg i c or nona l l erg i c reacti on to n i c kel

s u l fate were formed and the mean water vapour l os s of these groups was

cal cu l ated i n order to assess the i nfl uence of an a l l erg i c reacti on on

the barr ier funct i on of the s k i n . The res u l ts are presented i n Tabl e V

( see a l so F i g . 1A ) .

To eva l uate the i nfl uence of a n a l l erg i c reacti o n to n i ckel s u l fate on

the i rr i tancy of the other substances , the assoc i at i on between the a l l er­

g i c reacti ons to n i c kel s u l fate and the grades of eryth ema of the test

s i tes exposed to the d i fferent test substances was i nvestigated ( Tab l e

V I ) .

The i rr i tancy of sod i um l a uryl su l fate was i nf l uenced by a pos i t i ve patch

test reacti on to n i ckel s u l fate ( Kenda l l ' s tau correl ati on coeffi c i ent ,

0 . 42 ; p < 0 . 01 ) .

109

Di scuss i on .

Assoc i at i on between the erythematous effect of the test substances and

s k i n water vapour l os s .

I n t h i s study , sod i um l auryl su l fate was the on ly test substance for

wh i ch pos i t i ve s i gn i f i cant corre l ation between the degree of erythema

and the i ncrease of s k i n water vapour l os s was found (Tabl e I I ) . The

5 g/v% so lut ion of th i s potent i rr i tant ( Bj ornberg , 1 96B ) a s u sed i n

th i s study cau sed v i s i b l e ( i nfl ammatory ) react i ons i n most subj ects .

Sod i um l auryl su l fate l i ke other an ion ic surfactants a l so has a pro­

nounced effect on the barr i er fu ncti on of the s tra tum corneum ( van der

Val k et a l . , 1 984 ; Scheu p l e i n & Ros s , 1970 ) . The h i g h correl ati on

between erythema and water va pour l oss suggests that the extent of

cytotox i c damage to the v i ab l e cel l s of the epi dermi s and derm i s

paral l el s barr i er fu nct i on impa i rment for water . For phenol ( 5% ) and

d imethyl su l fox i de ( 50% ) , no pos i t i ve corre l at i on between the l os s of

water vapour and erythema was observed .

Dimethyl s u l fox i de i nfl uences the barr i er funct i on wi thout much structu­

ral damage ( Sweeney , Downes & Matol tsy , 1966 ) . It causes only extract i on

of some l i p ids , wh i ch may prevent compl ete restorat i on of barri er func­

t i on ( Scheup l e i n & Ros s , 1970 ) . ( Chappi ng was regu l ar ly obs erved i n

t h i s study after s k i n exposu re to d imethyl s u l fox i de ( 50% ) ) . The l ow

nons i gn i f i cant i ncrease i n water vapour l os s after exposure of the

s k i n to phenol ( 5% ) may be i nfl uenced by the effect of phenol on the

sweat g l and pores ( Dobson & Lobi tz , 1 957 ; Mal ten et a l . , 196B ) . Both

substances a l so have a cytotox i c effect on the v i ab l e cel l s of the epi ­

dermi s (Mal ten et a l . , 1 968; Baker & Kl i gman , 1967 ) .

I n th i s study , no pos i t i ve ( s i gn i f i cant ) correl at i on between water va pou r

l os s and v i s i b l e ( i nf l ammatory ) react i ons was observed for the s k i n ex­

posed to phenol ( 5% ) and d imethyl s u l fox i d e ( 50% ) , suggesti ng that for

these substances an i ncrease of water vapou r l os s does not para l l el the

extent of cytotox i c damage to the v i abl e cel l s of the epi derm i s and der­

mi s .

Th i s impl i es that a l i near rel at i on between barr i er functi on i mpai rment

and damage to the v i abl e cel l s of deeper l ayers of the s k i n may not be

110

TABLE I . Mean s k i n water vapour l os s from the s k i n exposed to the test substances

and d i st i l l ed water .

Persons with a l l erg i c Control grou p

react i ons to n i ckel s u l fate

n = 14 n = 9

mean (g/m2h )±so mean ( g/m2h ) ±so

S . V . L . 3 ) after n i c kel su l fate 6 . 8 ± 4 . 4 5 . 6 ± 3 . 6

S . V . L . after sod i um l aury1 su l fate 33 . 9 ± 2 1 . 7 1 3 . 7 ± 9 . 2

S . V . L . after d i methyl su l fox i de 8 . 9 ± 3 . 2 9 . 9 ± 3 . 6

s . v . L . after phenol 7 . 1 ± 7 . 3 4 . 1 ± 2 . 5

s . v . L . after d i s ti l l ed water 4 . 0 ± 1 . 3 3 . 6 ± 1 . 5

S i g n . 1 )

n . s . 2 )

p < 0 . 01

n . s .

n . s .

n . s .

1 ) S i g n i f i cance o f the d i fference between the group o f persons wi th a l l erg i c reacti ons t o n i c kel su l fate

and the control group ( a = 0 . 01 ) .

2 ) n . s . = not s i g n i f i cant .

3 ) S . V . L . = Sk in ( Water ) Vapour Loss .

....... ...... .--<

TABLE I I . S i gn i fi cance of the d i fferences between the mean i ncrease

in S . V . L . after exposure of the s k i n to the test substances as

compared with d i st i l l ed water ( control ) ( pa i red t-tests , t > 2 . 07 ;

p < 5% ) .

1 . ni ckel s u l fate

2 . sod i um l auryl su l fate

3 . d imethyl su l fox i de

4 . phenol

+) not s i g n i f i cant .

t-va l ue

2 . 95

5 . 29

8 . 62

1 . 60

s i g n i f i cance

p < 0 . 05

p < 0 . 05

p < 0 . 05

+ n . s .

TABLE I I I . Morphol ogi cal changes i n the s k i n (mean scores of

23 subj ects ) after a 48- hour exposure to the test substances .

erythema scal i ng fi ssuri ng

n i c kel su l fate 0 . 9 0 . 0 0 . 0

sodi um l auryl su l fate 1 . 8 0 . 1 0 . 2

d imethyl su l fox ide 0 . 7 0 . 0 0 . 4

phenol 0 . 2 0 . 0 0 . 0

d i s t i 1 1 ed water 0 . 0 0 . 0 0 . 0

1 1 2

TABLE IV . Assoc i a t ion between S . V . L . and erythema ( a s graded

accord i ng to a v i sual scor i ng system ) i n s k i n exposed to the

test substances .

Corre l a t i on Coeff i c i ent1 ) S i g n . 2 )

n i ckel s u l fate

sod i um l auryl s u l fate

d imethyl s u l fox i de

phenol

0 . 1 0

0 . 65

-0 . 36

0 . 23

1 ) Kenda l l ' s tau correl at i on coeff i c i ent .

2 ) Level of s i gn i f i cance a = 0 . 01 .

n . s .

p < 0 . 01

n . s .

n . s .

TABLE V . Mean water vapour l os s from the s k i n after a 48-hour exposure

to n i ckel s u l fate for the group wi thout an a l l erg i c reaction and those

wi th d i fferent grades of react i o n .

mean ( g/m2h ) ± SD

negat ive ( 9 subjects ) 5 . 6 ± 3 . 6

1+ react i on ( 2 subj ects ) 5 . 2 + 0 . 8

2+ react i on ( 5 subj ects ) 4 . 7 ± 1 . 2

3+ react i on ( 3 subj ects ) 7 . 6 ± 4 . 4

4+ react i on ( 4 subj ects ) 9 . 6 + 7 . 1 -

1 1 3

TABLE V I . Assoc i at ion between the grades of erythema of

adj acent s k i n exposed to a test su bstance and the grades

of a l l erg i c react i on to n i ckel su l fate .

n i c kel su l fate

sod i um l auryl s u l fate

d imethyl s u l fox i de

phenol

Correl ation coeff i c i ent 1 )

0 . 78

0 . 42

0 . 26

0 . 3 2

S i g n . 2 )

p < 0 . 01

p < 0 . 01

n . s .

n . s .

1 ) Kenda l l ' s tau correl ati on coeff i c i ent between erythema and

the a l l erg i c reacti ons to n i ckel su l fate .

2 ) Level of s i gn i f i cance a = 0 . 01 .

1 1 4

assumed beforehand and i s probabl y doubtfu l for many s ubstances .

Assoc i at i on between a l l ergi c patch test resu l ts for n i ckel su l fate and

s k i n water vapour l os s .

S k i n water vapour l oss was sometimes cons i derabl y i ncreased after expo­

sure to ni cke l su l fate , espec i a l ly if strong a l l erg i c reacti ons were

present ( Tabl e V ) .

However , not a l l a l l erg i c reacti ons l ead to d i sturbances of the horny

l ayer barr i er for water . Apparently , the horny l ayer was not (yet )

affect ed by the eczematous process or the funct i onal nature was reta i ned

or restored by adaptat ion or regenerati on , e . g . , by an i ncreased m i toti c

rate.

The i nfl uence of " s p i l l -over" react i ons and s k i n water vapou r l oss .

The erythematou s react ion of the s k i n to sod i um l auryl su l fate was

stronger i f pos i t i ve patch test react i ons to n i c ke l su l fate were

present on an adj acent area , i nd i cati ng a " sp i l l -over phenomenon" , i . e . ,

enhancement of an i rri tant react ion by an adj acent a l l erg i c reaction

( Bruynzeel et a l . , 1983 ) . { I t shou l d be noted that theoret i cal l y the

stat i sti ca l assoc i a t i on can a l so be expl a i ned by enhancement of a l l erg i c

react i ons by an adj acent i rri tant react i on ) .

T h i s i nd i cates that adj acent a l l erg i c react i on may i nf l uence the i rr i tant

response , wh i ch may secondari l y l ead to i ncreased s k i n water vapour l os s .

I t may b e concl uded that :

a ) A substance ( and i ts veh i cl e ) may have a primary { d i rect ) effect on

the horny l ayer by i nteract i on w ith horny l ayer components , resu l t i ng

i n i ncreased s k i n water vapour l os s .

b ) After permeation , a substance may el i c i t secondary ( a l l erg i c and

i rr i tant ) i nf l ammatory react i ons , wh i ch may a l so have del ayed effects

on the barri er functi on of water .

c ) D i rect damage to the horny l ayer may correspond w ith the extent of

the macroscop i ca l i nfl ammatory reacti ons of the s k i n , but th i s i s

not necessar i l y the case .

T h e s k i n water vapour l os s measu rements and t h e v i s i b l e changes i n the

1 1 5

s k i n are probab ly only partl y i nterdepend ent . The assoc i at i on between

the two parameters var i es from substance to substance . The concentrat ion

of the test substances wi l l probab ly a l so i nfl uence the assoc i at i o n . A

l ow concentrat ion of a su bstance may have an effect on the barr i er

funct i on for water wi thout el i c i t i ng v i s i b l e changes , whereas a h i gher

concentrat i on wi l l a l so cause macroscopi ca l changes in the s k i n .

I n the f i rst s i tuati o n , no s i g n i f i cant correl at i on wi l l be fou nd , i n

contrast w ith the second . The t ime of eva l uat ion wi l l a l so b e of impor­

tance , subs i d i ng of the erythema and restorat i on of the barr i er funct i on

hav i ng the i r own courses i n t ime .

I t may b e neces sary therefore t o assess the i rr i tancy o f a substance by

eva l uat i on of the s k i n barr i er funct ion as wel l as of the v i s i b l e i n­

fl ammatory response of the exposed s k i n . The eva l uati on shou l d be done

not on ly once , but by repeated measu rements ( time ser i es ) .

1 1 6

13

12

1 1

10

9

8

7

6

s � UJ (/) I. +I

_, 3 > (/) c 2 til Cll E

F i g . A .

f ±

0 1 +

I

2+ 3+ f. + patch test react ions

Mean s k i n vapour l os s (t S . E . M . } of the d i fferent patch test

reactions ( d i fferent grades o f a l l erg i c reacti ons ) to

n i ckel s u l fate .

1 1 7

References :

1 . Ba ker , H . & Kl i gman , A . M . ( 1 967 ) Measurement of transepi derma l

water l oss by el ectr i ca l hygrometry . Archi ves of Dermatol ogy , 96 ,

441 -452 .

2 . Bett l ey , F . R . ( 1 964 ) Non spec i f i c i rri tant reacti on i n eczematous

subj ects . Bri t i s h Journal of Dermato l ogy , 76 , 1 1 6 - 12 1 .

3 . Bett l ey , F . R . ( 1 97 2 ) The i rr i tant effects of detergents . Trans­

acti ons of the St. John ' s Hos p ita l Dermatol og i ca l Soc i ety , 58 , 65-74 .

4 . Bj Hrnberg , A . ( 1 968 ) Sk in reacti ons to pri mary i rri tants in pat i ents

with handeczema . Thes i s Oscar I sacsons Tryc ker i A . B . , GHtenborg .

5 . Bruynzeel , D . P . , N i eboer , C . , Boersma , D . M . , Scheper , P . J . & van Ke­

tel , W . G . ( 1 983 ) Al l erg i c react i ons , " s pi l l over " react i ons and T­

cel l subsets . Arch i ves of Dermatol og i c a l Research , 27 5 , 80- 85 .

6 . Da h l , M . V . & Tranci k , R . J . ( 1 977 ) Sod i um l auryl sul fate i rri tant patch

tests . Degree of i nf l ammat i on at vari ous t i mes . Contact Dermat i t i s ,

3 ' 263-266.

7 . Dobson , R . L . & Lobi tz , W . C . ( 1 957 ) Some h i stochem i ca l observati ons on

the human eccr i ne swea t g l ands . Archi ves of Dermatol ogy , 7 5 , 653-666 .

8 . Fros ch , P . J . & Kl i gman , A . M . ( 1 97 9a ) The Du hri ng Chamber . An i m­

proved techni que for epi cutaneous tes t i ng of i rri tant and a l l erg i c

react i ons . Contact Dermat i ti s , 5 , 73-81 .

9 . Frosch , P . J . & Kl i gman , A . M . ( 1 979b ) The soap chamber tes t . A new

method for asses s i ng the i rr itancy of soaps . Journa l of the Ameri can

Academy of Dermatol ogy , 1 , 35-41 .

1 0 . Hei s e , H . , Von Mattheu s , A . & Bru s t , B . ( 1 983 ) Irri tati onsprUfungen

in der Dermato l og i e , i hre Bedeutungen u nd Au ssage . Dermatol og i sche

Monatsschri ft , 169 , 63 1-637 .

1 1 . De Jong h , G . J . ( 1981 ) Poros i ty of human s k i n i n v i vo assessed i n

water l os s , carbon d i ox i de and el ectr i ca l impedance for heal thy

vol unteers , atop i c and psor i a t i c pat i ents . I n : Current Probl ems i n

Dermatol ogy : some fundamental approaches i n s k i n research ( Ed . by

J . W . H . Ma l i ) , Vol . 9 , 83- 10 1 . S . Karger , Basel .

1 2 . Von K i s s , G . ( 1 97 9 ) Mes sung der el ektri schen Impedanz zur Best immung

von durch Laugen bed i ngten Hautschadi gungen . Dermatol og i sche Monats -

1 18

schri ft , 1 6 5 , 526- 530 .

1 3 . Kl i gman , A . M . & Wood i ng , W . M . ( 1 967 ) A method for the measurement and

eva l uat i on of i rr i tants on human s k i n . Journal of I nvest igat i ve

Dermatol ogy , 49 , 78-94 .

1 4 . Mal ten , K . E . , Spru i t , D . , Boemaars , H . G . M . & de Kei zer , M . J . M .

( 1 968 ) Horny l ayer i nj ury by sol vents . Berufsdermatosen , 1 6 , 135- 147 .

1 5 . Mal ten , K . E . & Thi e l e , F . A . J . { 1973a ) Eva l ua t i on of s k i n damage I I .

Water l os s and carbon d i ox i de l oss rel ease measurements rel ated to

s k i n res i stance measu rements . Bri t i sh Jou rna l of Dermatol ogy , 89 ,

565- 569 .

1 6 . Ma l ten , K . E . & T h i e l e , F . A . J . { 1973 b ) Some measuri ng method s for the

eva l uat i on of orthoerg i c contactdermati t i s . Archi ves Bel ges de Derma­

tol og i e et de Syph i l i graph i e , 28 , 23-46 .

17 . Mal ten , K . E . & den Arend , J . ( 19 78 ) Top i ca l tox i c i ty of vari ou s con­

centrati ons of DMSO recorded w ith impedance measurements and water

vapour l oss measurements . Contact Derma t i t i s , 4 , 80- 92 .

1 8 . Ma l ten , K . E . ( 1981 ) Thoughts on i rr i tant contact dermat i ti s . Contact

Dermati t i s , 7 , 238-247 .

1 9 . Nater , J . P . { 1974 ) Techn i ek en moei l ij kheden van de l apj esproef .

I n : Contacteczeem , 23-27 . Stafl eu , Lei den .

20 . N i e , N . H . , Had l a i Hu l l , C . , Jenki ns , J . G . , S chei nbrenner , K . & Bent ,

D . H . { 1981 ) Stat i sti ca l package for the soc i a l s c i ences , 289- 290 .

McGraw-H i l l Book Company , New Yor k .

2 1 . N i l sson , G . E . ( 1 97 7 ) Measu rements o f water exchange through s k i n .

Med i ca l and B i o l og i ca l Eng i neer i ng and Comput i ng , 1 5 , 209- 2 1 5 .

2 2 . N i l s son , G . E . , Otto , U . & Wahl berg , J . E . { 1982 ) Assessment o f s k i n

i rr i tancy i n man by Laser Doppl er F l owmetry . Contact Derma t i t i s , 8 ,

401 -406 .

23 . Scheu p l e i n , R . & Ros s , L . ( 1970 ) Effects of surfactants and sol vents

on the permeabi l i ty of epi derm i s . Journal of the Soci ety of Cosmet i c

Chem i sts , 2 1 , 853-87 3 .

24 . Smeen k , G . { 1 968 ) De i nv l oed van deterg ent i a op de hu i d . Thes i s J .

Noorduyn en Zoon N . V . , Gori chem .

2 5 . Sweeney , T . M . , Downes , A . M . & f-latol t sy , A . G . ( 1 966 ) The effect of

DMSO on the epiderma l water barr i er . Journal of I nvesti gat ive

1 19

Dermato l ogy , 46 , 300- 302 .

26 . Van der Val k , P . G . M . , Cri j ns , M . C . , Na ter , J . P . & B l eum i n k , E .

( 1 984 ) S k i n i rri tancy of commerc i a l ly ava i l abl e soaps and detergent

bars as measured by water vapour l oss . Dermatosen in Beruf und

Umwel t , 3 , 87-90 .

28 . Wah l berg , J . E . ( 1 983 ) Assessment of s k i n i rr i tancy : mea surement of

s k i n fol d thi cknes s . Contact Dermat i t i s , 9 , 2 1-26 .

120

CHAPTER 6

THE I NFLUENCE OF LOW CONCENTRAT IONS OF IRRITANTS ON SK IN BARR I ER

FUNCT I ON AS DETERMI NED BY WATER VAPOUR LOSS

Accepted for pu b l i cat i on i n

Dermatosen i n Beruf und Umwe l t

1 2 1

Au thors :

P . G . M . v an der Va l k

J . P . Nater

E. B l eum i nk

Summary .

The effect of some i rr i tants on the barr i er funct i on of the s k i n was

assessed by means of wa ter va pou r l oss measu rements .

One-hundred mi crol i ters of the test substa nce i n d i s ti l l ed water were

appl i ed to the s k i n for a peri od of 48 hours , u s i ng l arge Fi nn chambers .

The exposures were done i n a test panel of 42 subj ects .

Sod i um l auryl su l fate ( 2% ) , cocobeta i ne ( 2% ) , crotona l dehyde ( 0 . 7 5v ) wi th

sod i um l auryl su l fate ( 0 . 5% ) and d i methyl s u l fox i de ( 50� ) mar ked l y

i nfl uenced water va pou r l os s .

Sod i um hydroxi de ( 1 % ) had l es s effect o n water vapou r l oss , a l though

the i ncrease wa s s i gn i f i cant (p < 0 . 05 ) . Phenol ( 5% ) and benza l koni um

ch l or i de ( 0 . 2% } d i d not s i g n i f i cantly i nfl uence the l os s of water

through the s k i n .

It i s concl uded that subc l i n i ca l effects of chem i ca l s o n the barr i er

funct i on may be of i mportance i n the devel opment of i rr i tant contact

dermat i t i s , but that th i s capac i ty i s probab ly not the only factor wh i ch

determi nes the potent i a l of a substance to contri bute to the devel opment

of i rr i tant contact dermat i t i s . A chem i ca l wh i ch has l i tt l e or no effect

on the funct i on of the horny l ayer may have a tox i c effect on the v i abl e

cel l s of deeper l ayers of the sk i n .

Th i s tox i c effect may a l so be a n important subc l i n i ca l factor i n the de­

vel opment of i rri tant contact dermat it i s .

I ntroducti on .

Whereas exposures o f the s k i n to strong i rr i tant factors l ead t o d i rect

and acute s k i n react i ons i n wh i ch a cause a nd effect rel at ionsh i p can be

establ i s hed w ith some certa i nty , thi s rel at i ons h i p i s as a ru l e l es s

evi dent i n chron i c i rr i tant derma ti t i s .

Preva i l i ng theory states that chron i c i rri tant contact dermati ti s may be

attr i butab l e to the cumu l at i ve effect of subc l i n i ca l doses of i rri tant

factors wh i ch i n themse l ves are not capab l e of produci ng c l i n i ca l effects

( 1 -3 ) .

I t i s hel d that barr i er funct i on impai rment of the stratum corneum p l ays

122

a rol e i n the devel opment of i rri tant s k i n reacti ons ( 3 , 4 ) .

The defi ci ent barri e r of the s k i n may l ead to i ncreased permeat ion of

chem ica l substances and th i s may faci l i tate tox i c effects upon the

v i ab l e cel l s of the epi derm i s and derm i s ( 4 , 5 ) .

I n strong i rri tant react i ons , the barr i er fu ncti on of the stratum cor­

neum wi l l be i mpai red by either the d i rect effect of the chem i ca l upon

the horny l ayer or i nd i rect l y by a severe tox i c ( eczematou s ) reaction

of the skin ( 5 ) .

The a im of t h i s study was to as sess the d i rect effect of some chem i ca l s

upon barr i er funct ion o f the s k i n . An attempt was made to expose the

s k i n to a concentrat i on whi ch may el i c i t subc l i n i ca l effects upon the

horny l ayer w ithout cau s i ng a severe tox i c react ion .

The barri er funct i on of the s k i n was eva l uated by means of s k i n water

vapou r l os s measurements ( 5- 7 ) .

Mater i a l s and method s .

The exposures were done i n a test panel of 4 2 subj ects (mean age 3 9 ±

1 7 . 5 y ; rang e , 16-83 yea rs ) . The panel cons i sted of pati ents w ith

mi scel l aneou s s k i n d i seases ( l oca l i zed eczema , u l cu s cruri s , psori a s i s ,

etc . ) v i s i t i ng the outpati ent department for a l l erg i c patch tes t i ng . The

fol l owi ng test su bstances were appl i ed on c l i n i ca l l y unaffected s k i n

o f the vol ar s i de o f t h e forearm { g/v% i n d i st i l l ed water ) :

sod i um l auryl su l fate ( 2g/v%) pH 7 . 3

cocobetai ne ( 2 g/v% ) pH 5 . 2

croton a l dehyde ( 0 . 7 5 g/v% ) wi th sod i um l auryl pH 4 . 8

su l fate ( 0 . 5 g/v% )

d imethyl s u l foxi de ( 50 g/v% ) pH 7 . 1

phenol ( 5 g/v% ) pH 6 . 2

sod i um hydrox i de { 1 g/v% ) pH 1 2 . 7

benza l kon i um ch l or ide ( 0 . 2 g/v% ) pH 6 . 6

d i s ti l l ed water pH 6 . 5

The substances were tested (on the bas i s of a prel im i nary study ) i n these

concentrati ons in order to el i c i t s l i ght macroscopi cal l y v i s i b l e changes

123

i n the s k i n , i . e . , on ly s l i ght or moderate erythema , s l i ght scal i ng or

fi ssu r i ng ( 1+ or 2+ reacti ons as descri bed by Frosch & Kl i gman ( 1 97 9 ) )

( 8 ) .

I n these concentrati ons , subc l i n i cal effects on the barri er funct i on

can be expected . The exposures were done for a per i od of 48 hours by

means of a chamber method ( F i nn c hamber , Epi test Ltd . Oy , Hel s i nki ,

F i n l and ) . The a l um i n i um cups wi th a d i ameter of 12 mm , and fi tted wi th

5 pi eces of absorb ing pa per ( Whatma n ) were saturated wi th 1 00 � 1 of the

test substance .

At 24 hours after the exposu res , s k i n water vapour l oss was measured by

means of the Servo Med Evaporimeter ( Servo Med , Stockho l m , Val l i ng by ,

Sweden ) accord i ng to methods descri bed i n deta i l el sewhere ( 6 , 7 ) .

Th i s i ns trument i ncl udes a measuri ng probe wh i ch reg i sters vapour l os s

o f a s k i n area correspond i ng w ith t h e s i ze o f t h e exposed s k i n .

S k i n water vapour l oss was determi ned after a res t i ng per i od of at l east

1 5 mi nutes . The measurements were done under neutral envi ronmenta l c i r­

cums tances ( 21 . 0°C . � 1 . 9 ; rel ati ve hum id i ty , 42 . 1� ! 9 . 6 ; s k i n tempe­

rature , 3 1 . 5°C � 1 . 2 ) .

Stati st ica l method s .

S k i n water vapour l oss from the exposed s k i n was compared wi th that of

unexposed s k i n . The d i fferences were tes ted for s i g n i f i cance by u s i ng a

t-test for pai red observati ons ( 9 ) .

Res u l t s .

Water vapour l oss from the s k i n s i tes ex posed t o the test substances and

from unexposed s k i n i s g i ven i n Tab l e I . The surface act i ve agents

( sod i um l auryl su l fate ( 2% ) , cocobeta i ne ( 2% ) and sod i um l auryl su l fate

in combi nat ion wi th crotona l dehyde ( 0 . 7 5%) ) , except for benza l kon ium

ch l or ide ( 0 . 2% ) ( ta ke note of d i fferent concentrati on ) , cons i derab ly

i ncreased water vapour l oss i n compari son w ith unexposed s k i n . D imethyl

s u l foxi d e ( 50%} and sod i um hydrox i d e ( 1% } a l so i ncreased s k i n water

vapour l os s . Phenol ( 5% ) d i d not negat ive ly i nfl uence the barri er func-

124

t i on for water ( i n the appl i ed concentrati on ) . The d i fferences between

s k i n exposed to the test substances and unexposed s k i n were s i g n i f i cant ,

except for phenol ( 5% ) and benzal kon i um ch lor ide ( 0 . 2% ) ( a = 0 . 05 ) .

D i scuss i on .

I n th i s study , an attempt was made to expose the s k i n t o chem i ca l s i n a

concentration el i c i t i ng subcl i n i cal effects on the barr i er funct i on

wi thout the devel opment of man i fest tox i c react i ons , a l though i t shou l d

be noted that accurate assessment o f such a concentrati on i s d i ff i c u l t

becau se o f the occurrence o f l arge i ntra- and i nter i nd i v i dual d i fferen­

ces i n reacti on to i rr i tants { 10 ) .

A pre l i m i nary study revea l ed that h i g her concentrati ons than those used

i n th i s study cause severe tox i c react i ons i n s ome i nd i v i dua l s . For

exampl e , benza l kon i um ch l or ide proved to have a greater i rr i tant poten­

t i a l i n compari son w ith the other tested su rfactants and had to be

tested i n a l ower concentrati on .

The subcl i n i ca l effect on barri er funct i on a s d etermi ned by s k i n water

vapour l os s var i ed among the test substances . Benza l koni um chl oride

( 0 . 2% } and phenol ( 5% ) , a l though cau s i ng i rr i tant effects i n h i g her

concentrat i ons , hard ly i nfl uenced the barr i e r functi on of the s k i n ( as

determ i ned by water vapour l os s ) .

Apparentl y , some i rr i tants act by exert ing a subcl i n i ca l effect on the

barri er fu ncti on , whi l e others fa i l to do so .

Therefore , eva l uat i on of the subcl i n i ca l effects of chem i ca l s upon

barri er functi on may be u sefu l only i nsofar as stratum corneum i ntegri ty

i s important to prevent the permeati on of chem i ca l s and consequently

to prevent the devel opment of i rr i tant or a l l erg i c contact derma t i t i s

( 3 , 4 ) .

I t must be cons i dered that subcl i n i ca l effects other than i mpai rment of

barr i er funct i on may pl ay a rol e i n the devel opment of chron i c i rr i tant

contact dermati t i s ( 1 1 ) . After penetrat i on of a substance through the

horny l ayer wi thout primari l y i mpa i r i ng the horny l ayer funct i ons ,

damage to the v i ab l e cel l s of the epidermi s a nd dermi s may occur and thi s

may l ead to the devel opment of i rr i tant contact dermati t i s ( 5 ) .

1 25

Thus , subcorneal l ayers may be subcl i n i ca l l y damaged , whi l e at the same

time no measura b l e effects on the barrier functi on of the s k i n can be

noted .

126

TABLE I . Mean vapour l ass 2 + {g/m - S . D . ) from ex posed and unexposed s k i n

S . D . s i g n . +

mean

sod i um l auryl su l fate 6 . 4 3 . 6 p < 0 . 05

cocobeta i ne 5 . 1 2 . 7 p < 0 . 05

crotona l dehyde w i th sod i um l auryl su l fate 5 . 1 5 . 9 p < 0 . 05

d imethyl su l fox ide 5 . 3 4 . 3 p < 0 . 05

phenol 2 . 7 0 . 9 ++ n . s .

sod i um hydroxi d e 3 . 6 2 . 0 p < 0 . 05

benza l kon i um chl oride 3 . 0 1 . 4 n . s .

d i st i l l ed wa ter 2 . 5 1 . 1 n . s .

control 2 . 5 1 . 0

+ ) S i g n i f i cance of the di fference between the expos ed s k i n s i te and

the unexposed s k i n (a = 0 . 05 ) .

++ ) n . s . = not s i gn i f i cant .

127

References

1 . Mal ten , K . E . , Thi el e , F . A . J . Some theoreti cal as pects of ' ortho­

erg i c ' ( = i rri tant ) dermati t i s . Arch . Bel g . Derm . 28 : 9-22 ( 197 2 ) .

2 . Hagerma n , G . Uber das traumi terati ves ( tox i sche ) Ekzem . Dermato l o­

g i ca 1 1 5 : 525-529 ( 1 957 ) .

3 . Mal ten , K . E . Thoughts on i rri tant contact dermat i t i s . Contact Derma­

t i t i s 7 : 238-247 ( 1 981 ) .

4 . Ummenhofer , B . Hornsch i chtphys i ol og i sche Grund l agen der Pravent i on

und Reha bi l i tati on von Berufsekzemen . Dermatosen 29 : 1 02- 106 ( 1981 ) .

5 . Va l k , P . G . M . van der , Kru i s -de Vr ies , M . H . , Nater , J . P . , Bl eumi n k ,

E . , Jong , M . C . J . M . d e . Eczematous ( i rr i tant and a l l erg i c ) react i ons

of the s k i n and barri er function as determi ned by water vapour l oss

Accepted for pub l i cati on . C l i n . & Exp . Derm .

6 . N i l s son , G . E . Measu rement of water exchange through the s k i n . Med .

& B i o l . Eng . & Comput . 1 5 : 209- 2 1 5 ( 1 977 ) .

7 . Va l k , P . G . M . van der , Nater , J . P . , B l eumi n k , E . S k i n i rri tancy of

su rfactants as assessed by water vapou r l os s measurements . J . I nvest .

Dermatol . 82 : 291-293 ( 1 984 ) .

8 . Frosch , P . J . , Kl i gma n , A . M . The soap chamber tes t . J . Am . Acad .

Derma tol . 1 : 35-41 ( 1979 ) .

9 . N i e , H . N . , Had l a i Hu l l , C . , J enki ns , J . G . , Stei nbrenner , K . , Bent ,

D . H . Stati s t i ca l package for the soci a l sc i ences . McGraw-Hi l l Book

Company , New York pp 267-274 ( 1 97 5 ) .

1 0 . Bj ornberg , A . S k i n react i ons to primary i rri tants i n pat i ents wi th

hand eczema . Thes i s , Oscar I sacsons Tryckeri AB , Goteborg , Sweden

pp 1 38- 142 ( 1 968 ) .

1 1 . Prottey , C . The mol ecu lar bas i s of s k i n i rr itat ion . Cosmet i c Sci ence

vol I . Academ i c Press , London pp 275-349 ( 1 978 ) .

128

CHAPTER 7

SK IN I RRITANCY OF COMMERC IALLY AVAI LABLE SOAP AND DETERGENT

BARS AS MEASURED BY WATER VAPOUR LOSS

Dermatosen i n Beruf und Umwel t

3 : 87-90 { 1 984 )

129

Authors :

P . G . M . van der Val k

M . C . C r i j ns

J . P . Nater

E. B l eumi nk

Summary

The i rri tancy on human s k i n of 13 toi l et soaps was asses sed by means of

water vapour l oss measurements . The tests were performed on heal thy s k i n

o f the vol ar s i de of t h e forearm i n a panel o f 3 3 subjects . The exposu­

res were done u s i ng the F i nn chamber method . S k i n water vapour l oss was

measured by means of an ' evaporimeter ' . Al l soaps - tested i n 2 g/v% so­

l ut i ons - were found to l ead to a stat i st i ca l l y s i gn i fi cant i ncrease of

water vapour l oss as compared to the control s i tes . Syntheti c detergents

based on a l kyl su l fates , part i cu l arly Lactacyd , genera l l y had a rel at i ­

vely greater effect o n s k i n vapour l oss a s compared wi th the other pro­

ducts . On the whol e the d i fferences between the products were sma l l . I t

appears that every person probab ly has h i s own pattern of suscept i b i l i ty

to wash-acti ve agents .

I ntroduct i on

Soaps and detergents u sed for c l eans i ng t he s k i n may damage the s k i n ei ­

ther by i nfl uenci ng i t s barri er funct i on or by cau s i ng tox i c reacti ons i n

the epi derm i s o r dermi s ( 1-4 ) . A faci l i tated permeation of substances may

enhance sens i t i zat ion to a l l ergens present i n the c l eans i ng materi a l or

to other a l l ergens i n the envi ronment ( 5-7 ) . I rr i tant effects may i n the

l ong run contri bute to the deve l opment of i rri tant contact dermat i t i s .

The importance of l ow concentrati ons of surfactants i n cau s i n g and sus­

tai ni ng i rr i tant contact dermati t i s is st i l l i n d i scuss i on . Soaps and

synthet i c detergents commonly cause only s l i ght i rri tati on when tested on

the s k i n i n concentrati ons comparabl e to soa p d i l uti ons used for was h i ng

( 8 , 9 ) . I t i s , however , l i kely that the i rri tant effects of soaps and de­

tergents are cumu l ati ve in the course of time ( 5 , 8 ) . Moreover a certa i n

percentage of i nd i v i du a l s comp l a i ns about dryness and i tch i ng of the s k i n

after u s i ng c l eansi ng products { 10 ) . Therefore i t i s mandatory t o advi se

subj ects with adverse react ions to certa i n soaps or detergents other pro­

ducts wh i ch are better tol erated , i . e . products that do not conta i n com­

ponents that may g i ve ri se to a l l erg i c reacti ons and a l s o have as l i tt l e

i rri tant effects o n the s k i n a s poss i b l e ( 7 , 8 , 1 0- 14 ) .

130

I n order to i nvesti gate the i rri tant effects of soaps and detergents the

d i fferent components have been stud i es ( 1 5 - 1 7 ) . However , the i rri tant ef­

fect of c l eans ing products cannot be estimated re l i ab ly on the bas i s of

data obta i ned from the i ngred i ents a l one ( 18 ) . The total product must a l ­

s o b e tes ted to assess i ts i rri tancy .

I n t h i s study an attempt was made to test l ow concentrati ons of a number

of soap and detergent bars commerc i a l l y ava i l ab l e i n the Netherl ands for

the i r i rr i tancy to human sk i n .

The effect of the products o n the s k i n was asses sed by water vapour l oss

measurements ( 1 3 , 14 , 1 9 ) .

Materi a l s and methods

Thi rteen brand- name products were eva l uated dur i ng the months Apri l and

May on a panel of 33 hea l thy subj ects , rang i ng i n age from 18 to 52 years .

The exposures were performed u s i ng a c hamber method ( Large Fi nn chamber ,

Epi test Ltd . , Oy Hel s i nk i , F i n l a nd ) . Each F i nn chamber w ith a d i ameter of

12 mm conta i ned 5 c i rcu l a r p i eces of absorbent paper { Whatmann ) . By means

of a mi cropi pette {Ass i sten t , Karl Hecht , Sondheim/ Rhon , FR Germany ) th i s

p i eces of absorbent paper were saturated wi th 100 � 1 of a test substance .

I n total 16 F i nn chambers on Scanpor ( Norgesp l aster A/S Os l o , Norway ) we­

re used . Th i rteen were fi l l ed wi th 2 g/v% of the soap or detergent i n d i s ­

ti l l ed water. Th ree were used as control s . The chambers were appl i ed to

the vol ar s i de of the forearm . The brand names of the tested products and

add i t i ona l i nformati on are l i sted in Tab l e 1 . F i xomu l l stretch (Bei ers­

dorf , Hamburg, FR Germany ) and No 1 1 e 1 ast bandage ( Lohmann , Neuwi ed , FR

Germany ) were used for f i x i ng the chambers to the s ki n . After an exposure

of 24 hours and an off- peri od of one hour to reduce effects of macerat i on

and desorpti on ( 20 ) the actual measurements were done .

S k i n water vapour l os s measurements were performed by means of the Servo

Med evaporimeter { Servo Med , Stockhol m , Val l i ng by , Sweden ) . Th i s i nstru­

ment compri ses a probe attached to a portabl e d i s p l ay un i t . The probe i s

appl i ed perpendi cu l ar to the s k i n . I n the probe two pai rs of both a humi ­

j i ty transducer and a thermi stor are s i tuated at d i fferent l evel s . From the

s i gna l s of the sensors the s k i n water va pour l oss per unit t i me and sur-

1 3 1

Ta b l e 1 . I n forma t i on about the tes ted produ cts .

Brand name

Aveenoderm

C i da l

Johnson ' s baby soap

Lactacyd

Lux

Neutrogena

Pa lmo l i ve

Seba med

Sebopona

Sporex

Sul foderm

Un i cura

Zwi tsa l baby soap

Compo s i t i on accord i ng pH

to manufacturer*

Synthet i c detergent 5 . 43 conta i n s sodi um l auryl ester su l fonate

Sod i um soap of tal l ow- and 10 . 6 1 coconut o i l

Sod i um soap of tal l ow- and 1 0 . 65 coco nut o i l

Synthet i c detergent conta i n s 3 . 84 ammon i um a l kyl s u l fate

Sod i um soap of tal l ow- and 9 . 68 coconut o i l

Sod i um soap of coconut o i l 9 . 7 5

Sodi um soap of tal l ow- and 10 . 59 coconut o i l

Synthet i c detergent 5 . 50 conta i n s a l kyl s u l fates

Syntheti c detergent 6 . 68 conta i ns a l kyl s u l fates

Pure sod i um soap of coconut o i l 10 . 63

Synthet i c detergent conta i n s 5 . 88 sod i um s u l fsucci nate

Sodi um soap of tal l ow- and 10 . 60 coconut oi l

Sod i um soap of tal l ow- and 10 . 60 coconut o i l

* Only ma i n components are ment i oned .

1 32

face can be ca l cu l ated . A fu l l descri pt i on of t h i s i nstrument i s g i ven by

N i l s son ( 2 1 ) . Reg i stration and measur i ng techn ique were performed accor­

d i ng to methods descri bed e l sewhere ( 1 9 ) . Measu rements were performed un­

der neutral amb i ent c i rcums tances ( room temperature var i ed from 20 to 22° C ; the mean rel a t ive h umi d i ty was 36 . 4 � 5 . 4 ) .

Stat i s t i c analys i s

A two-way ana l ys i s of vari ance was done to test the contri but i o n o f the

products ta k i ng i nto accou nt the i ntersubj ect vari abi l i ty ( 22 ) . To test the actual d i fferences for s i g n i f i cance a pai red t-test was used .

The assumpt i on of a Gauss i an frequency d i str ibut i on proved to be l eg i t i ­

mate ( 19 ) . To avoid a cumu l at i ve type 1 error proba bi l i ty the Newman­

Keu l s mul t i p l e compari son test procedure was used ( 22 , 23 ) . Th i s conser­

vati ve procedure prov i des a l evel of s i gn i f i cance for the ent i re col l ec­

t i on of tests , implyi ng that the probab i l i ty of obta i n i ng spurious s i g n i ­

fi cant resu l ts does not exceed th i s l evel .

Res u l ts

I n Tab l e 2 the rank order of the tes ted products i s l i sted accord i ng to

the effects on water vapour l os s of the s k i n . Al l products caused a s i g­

n i f i cant i ncrease of water vapour l oss as compared to the control s ( p <

0 . 05 ) . The ana lys i s of var i ance performed on the data showed a s i gn i f i ­

cant contr i but i on o f the products i n cau s i ng the vari ati on . Th i s i nd i ca­

tes that , though d i fferences between products were most ly sma l l , the mean

water vapour l os s va l ues of the exposed s k i n s i tes do not on ly d i ffer by

chance { Tab l e 3 ) .

The actual d i fferences were tested by means of pa i red t-tests { Tabl e 4 ) .

By means of the Newman-Keu l s mu l t i p l e compari son procedure an attempt

was made to order the products i nto groups wi th more or l ess the same ef­

fect on water vapour l os s . Th i s procedure showed a l a rge i ntermed i ate

group of ma i n ly a l ka l i ne soaps wi thout s i g n i f i cant d i fferences . Lactacyd

caused a s i gn i fi cant i ncrease i n water vapour l oss w i th regard to other

products . Sebopona di ffered s i gn i f i cantly from Aveenoderm to C i da l . Seba-

1 33

Tab l e 2 . Rank order of sk i n vapour l os s va l ues of the d i fferent test

substances .

Mean ( g/m2 . h . ) S . D .

1 . Empty F inn chamber 6 . 573 1 . 972

2 . Sod i um chl oride 0 . 9% 6 . 7 1 8 2 . 057

3 . Di st i l l ed water 7 . 388 1 . 9 1 7

4 . Aveenoderm 8 . 333 3 . 276

5 . Zwi tsa l baby soap 8 . 79 1 2 . 4 1 1

6 . Neutrogena 8 . 900 2 . 7 1 0

7 . Sporex 8 . 945 2 . 590

8 . Pa lmol i ve 8 . 99 1 2 . 286

9 . Su l foderm 9 . 030 2 . 6 1 1

10 . Uni cura 9 . 1 7 3 2 . 63 5

1 1 . Lux 9 . 281 2 . 445

1 2 . C i da l 9 . 239 2 . 986

1 3 . Johnson ' s baby soap 9 . 809 3 . 1 7 5

1 4 . Seba med 9 . 909 3 . 049

1 5 . Sebopona 10 . 464 3 . 542

16 . Lactacyd 1 1 . 236 2 . 972

1 34

Tabl e 3 . Analys i s of vari ance , water vapour l os s va l ues by soap and

subj ect .

Soap

Source of

var i at i on

Subj ect

Res i dual

Tota l

Sum of squares

241 . 165

2420 . 73 1

947 . 089

3608. 985

135

OF

1 2

3 2

3 84

428

F

8 . 1

30 . 7

S i gn . F

p < 0 . 001

p < 0 . 001

Tab l e 4 . T-val ues ; pa i red t-tests between SVL-va l ues of the di fferent test substances�) .

1 . Aveenoderm 0

2 . C i da l - 3 . 00 0

3 . J ohnson - 4 . 00 - 1 . 67 0

4 . Lactacyd -6 . 3 1 - 5 . 1 9 -3 . 45 0

5 . Lux - 2 . 33 0 . 06 1 . 47 5 . 16 0

6 . Neutrogena - 1 . 81 1 . 2 1 2 . 94 5 . 70 1 . 19 0

7 . Pa lmo l i ve - 1 . 56 0 . 69 2 . 23 4 . 92 0 . 63 -0 . 3 1 0

8 . Seba med - 3 . 49 - 1 . 65 -0 . 2 1 2 . 80 - 1 . 54 - 2 . 52 - 2 . 38 0

9 . Sebopona - 4 . 34 - 2 . 50 - 1 . 25 1 . 52 - 2 . 53 -3 . 59 - 3 . 10 - 2 . 1 7 0 "' M

10 . Sporex - 1 . 49 0 . 7 7 2 . 1 6 5 . 92 0 . 84 -0 . 16 0 . 14 3 . 10 3 . 93 0

1 1 . S u l foderm - 1 . 67 0 . 52 1 . 7 2 4 . 95 0 . 55 -0 . 36 -0 . 10 2 . 24 2 . 96 -0 . 34 0

1 2 . Un i cu ra - 2 . 22 0 . 19 1 . 53 5 . 36 0 . 13 -0 . 84 -0 . 50 2 . 1 6 3 . 41 -0 . 7 2 -0 . 44 0

1 3 . Zwi tsal - 1 . 1 7 1 . 1 4 2 . 3 5 6 . 04 1 . 37 0 . 33 0 . 53 2 . 90 4 . 00 0 . 47 0 . 7 1 1 . 95 0

1 ) 2 ) 3 ) 4 ) 5 ) 6 ) 7 ) 8 ) 9 ) 1 0 ) 1 1 ) 1 2 ) 13 )

� ) t > 2 . 042 , p < 0 . 05 .

med and Johnson ' s Baby Soa p d i ffered s i gn i fi cant ly from Aveenoderm � ) .

Di s cu s s i on

I n the app l i ed 2 g/v � so l u t i on a l l tested products were found to l ead to

a s i ng i f i cant i ncrease of water vapour l os s in compar i son to the contro l

s i tes ( p < 0 . 05 ) . Th i s i ncreas e of water vapour l os s poi nts to a l terati ­

ons of s k i n permeabi l i ty .

I n compari son t o a l ka l i ne soaps syntheti c detergent bars based o n a l kyl

s u l fates , espec i a l ly Lactacyd , appear to exert a s l i ght ly s tronger effect

on the s k i n . Lactacyd a l so conta i ns , apart from ammon i um a l kyl s u l fate ,

l acti c ac i d . Th i s su bstance probab ly has ant i - bacteri a l propert i es , but

a l so may affect the protei ns of the horny l ayer ( 24 ) . So l act i c ac i d may

contri bute to the i ncrease of s k i n water vapour l os s , a s observed i n t h i s

study . The a l ka l i ne s oaps were not found t o i nf l uence water l os s t o a

greater extent than the synthet i c products (wi t h excepti on of Aveenoderm ) .

Thu s the often c l a imed advantages of products wi t h a neutra l or ac i d pH

in compar i son to a l ka l i ne soaps wi th respect to the i r i nj uri ng effect of

the s k i n ( 2 5 ) cou l d not be proven .

Under neutra l c i rcumstances the pH of the s k i n var i es from 5 . 2 to 6 . 0 and

is kept wi th i n these l i m i t s by the " funct i ona l buffer capa c i ty of the

s k i n " , rna i n ly a 1 actate-b i carbonate buffer system ( 26 ) . The importance of

stri ct mai ntenance of the ac i d pH , the " a c i d ma nt l e of the s k i n " ( 2 7 )

seems to b e overemphas i s ed , a s on ly very a l ka l i ne ( buffered ) substances

i nj ure the s k i n structura l l y ( 28 ) . Present ly some i nvest i gators even ad­

vocate the use of a l ka l i ne soaps ( 29 , 30 ) .

Especi a l l y sod i um s oaps of l ong cha i n fatty ac i ds are adv i sed , because

fatty acids of a l ower mo l ecu l a r wei ght more frequently y i e l d i rr i tant

react i ons ( 1 6 , 3 1 ) . E spec i a l l y for subj ects with a " v u l nerabl e s k i n " the

use of these a l ka l i ne soaps shou l d m i n i mi ze the r i s k of adverse react i ­

ons ( 30 ) . The i rri tancy of synthet i c detergents cannot be genera l i zed

however , s i nce products based on i sethi onates seem to have a rel at i vel y

good s k i n compat i b i l i ty ( 10 ) .

� ) Tabu l ati on ava i l ab l e from the authors .

137

Genera l l y we only observed sma l l d i fferences between commerc i a l toi l et

soaps , even between chemi cal ly unre l ated surfactants . I t i s noteworthy

that i n the avai l ab l e l i terature cl ear d i fferences have only been obser­

ved i n stud i es ma k i ng use of repeated exposu res of h i gh concentra t i ons of

the products ( 10- 12 ) . For the popu l ati on as a who l e i t genera l l y may hol d

true that some cl eans i ng products are better tol erated than others , but

in the i nd i v i dua l case t h i s i s not neces sari ly tru e . It i s not poss i b l e

t o pred i ct the i ntens i ty of the s k i n react i on o f a n i nd i v i dual t o an i rri ­

tant ( 32-34 ) . Th i s i s al so pl aus i b l e for su rface acti ve agents ( 1 9 , 32 ) .

Thi s impl i es that every subject may have i t s own pattern of suscept i b i l i ­

ty to soaps and detergents . D i fferences i n " s k i n type" probab ly determ i ne

wh i ch products are wel l tol era ted . For examp l e persons w i t h a severe se­

borrhoea may tol erate a strong l y degrea s i ng produ ct , wh i ch on the other

hand may cause s i de effects i n peop l e wi th a dry and more sens i t i ve s k i n

( 3 5 , 36 ) .

1 38

References

1 ) Bettl ey , F . R . , Donaghue , F . The i rri tant effect of soap upon the nor­

ma l s k i n . Br . J . Dermatol . 7 2 : 67-76 ( 1 960 ) .

2 ) Bett l ey , F . R . The i nf l u ence of soap on the permeab i l i ty of the epi ­

dermi s . Br . J . Dermato l . 73 : 448-454 ( 1961 ) .

3 ) Bett l ey , F . R . The i rr i tant effect of detergents . Transacti ons St .

John ' s Hos p i ta l Dermatol . Soc . 58 : 65-74 ( 19 72 ) .

4 ) Val er , M . D i e verg l e i chende Untersuchung der Rei zw i r kung von Wasch­

mi ttel n auf d ie menschl i che Haut . Berufsdermatosen 1 7 : 83-99 ( 1969 ) .

5 ) Mal ten , K . E . Thoughts on i rri tant contact dermat it i s . Contact Derma­

t i t i s 7 : 238-247 ( 1 981 ) .

6 ) Ummenhofer , B . Hornsch i chtphys i o l og i sche Grundl agen der Pravent i on

und Rehabi l i tat i on von Berufsekzemen . Dermatosen 28 : 102- 106 ( 1981 ) .

7 ) Ummenhofe r , B . Prakt i s che berufsdermatol og i sche As pekte der Hautre i ­

ni gung . Zent . B l . Haut-Gesch l . Krankh . 147 : 379-449 ( 1982 ) .

8 ) Ki s s , G . von . PrUfung von durch Waschmi ttel bedi ngten Hautsch�d i gung­

en . Dermatosen 29 : 1 5- 1 8 ( 1981 ) .

9 ) Jansen , L . H . , Young , E . Mag eczemateus veranderde hu i d gewassen wor­

den? Ned . T . Geneesk . 1 06 : 7 10-7 1 5 ( 1962 ) .

1 0 ) Frosch , P . J . I rri tancy of soaps and detergent bars . I n : Pr i nc i p l es of

Cosmeti cs for the Derma tol og i st , pp 5- 12 ( 1 982 ) Edi tors : Frost and

Horwi tz . Mosby St . Loui s .

1 1 ) Frosch , P . J . , Kl i gman , A . M . The soap chamber test . J . Am . Acad . Der­

matol . 1 : 35- 4 1 ( 1979 ) .

1 2 ) Ketel , W . G . van , Bruynzee l , D . P . , Bezemer , P . O . , Stamhu i s , I . H . Toxi ­

c i ty of handc l eaners . Dermatol oqi ca 168 : 94-99 ( 1984 ) .

1 3 ) Has s i ng , J . H . , Nater , J . P . , B l eum i n k , E . I rr i tancy of l ow concentra­

t i ons of soap and syntheti c detergents as measured by s k i n vapour

l os s . Derma to l og i ca 1 64 : 3 14-321 ( 1 982 ) .

1 4 ) Val k , P . G . M . van der , Nater , J . P . , B l eum i n k , E . S k i n vapour l os s as a

method for measuri ng the i nfl uence of soaps and detergents on human

s k i n . Dermatosen 3 1 : 58-60 ( 1983 ) .

1 5 ) B l ank , I . H . Acti on of soap on s k i n . Arc h . Derm . & Syph . 39 : 8 1 1 -824

( 1939 ) .

139

1 6 ) Tronn i e r , H . Uber d i e Abhang i g kei t dermato l og i scher E i genschaften

waschakti ver Tens i de von deren Kettenl ange . ParfUm . u . Kosmet . 58 :

60-65 ( 1977 ) .

1 7 ) Smeen k , G . De i nv l oed van detergent ia op de hui d . Thes i s , J . Noor­

duyn en zoon N . V . , Gori chem ( 1968 ) .

1 8 ) Gol demberg , R . L . , Safri n , L . R�duct i on of topi cal i rr i tat i on . J . Soc .

Cosmet . Chern . 28 : 667-679 ( 1977 ) .

1 9 ) Val k , P . G . M . van der , Nater , J . P . , Bl eu� i n k , E . S k i n i rri tancy of

surfactants as assessed by water vapor l oss measurements . J . I nvest .

Derma to l . 82 : 291 -293 ( 1 984 ) .

2 0 ) Baker , H . , Kl i gman , A . M . Measurements of transep i derma l water l os s

by el ectr ica l hygrometry . Arc h . Derm . 9 6 : 441-452 ( 1 967 ) .

2 1 ) N i l s son , G . E . Measurements of water exchange through sk i n . Med . B i o l .

Eng . & Comput . 1 5 : 209-2 18 ( 1 977 ) .

22 ) Arm i tage , P . Stat i s t i ca l methods i n med i ca l research , 7 : 189-2 1 6 .

B l ackwel l Sci ent if i c Publ i cati ons , Oxford , U . K . ( 19 7 1 ) .

23 ) Mi l l er , R . G . S imu l taneous stat i s t i cal i nfP.rence , 6 : 82-90 . McGraw­

H i l l Boo k Company , New York , U . S . A . ( 1966 ) .

24 ) Th i el e , F . A . J . The s k i n d i s i nfectant propert i es of l act i c ac i d . I n :

Handbuch der Haut- und Gesch l echts krankhei ten , Vol . 1 /4B , pp 257-258

( 1981 ) Normal e und Patho l og i sche Phys i ol og i e der Haut I I I . Ed i tor :

J . Jadassohn . Spri nger-Verl ag , Berl i n .

2 5 ) Bettl ey , F . R . , Donaghue , E . The i rri tant effect of soap upon the nor­

ma l s k i n . Br . J . Dermatol . 72 : 67-76 ( 1 980 ) .

26 ) Kl aschka , F . Arbei tsphys i o l og i e der Hornsch i cht i n GrundzUgen . I n :

Handbuch der Haut- und Ges chl echts kran khei ten , Vol . 1 /4A , p p 184- 185

( 1 979 ) Norma l e und Patho l og i sche Phys i ol og i e der Haut I I . Edi tor : J .

J adassohn . Spri nger-Ver l a g , Berl i n .

27 ) Schade , H . , March i oni n i , A . P hys i ka l i s ch - chemi sche Untersuchungen

an mensch l i cher Hau t . Kl i n . Wsch r . 1 : 1 - 1 4 ( 1928 ) .

28 ) Tronn i er , H . D i e potent i ometri sche T i trat i on a l s Methode zur Best im­

mung der Al kal i empf i nd l i ch ke i t der Haut . Berufsdermatosen 1 4 : 296-

308 ( 1966 ) .

2 9 ) Mal ten , K . E . Tens i de ( Nederl ands ) = Ten s i de ( Du i ts ) = Surfactants

( Engel s ) z i j n bel angri j ke componenten i n de cosmet i ca . N i euwsbr ief

1 40

Conta ctdermatol ogi e 4 : 47-53 ( 197 3 ) .

30 ) Mal ten , K . E . De zeep waarmee wij ons wassen . N i euwsbrief Contactder­

matol og i e 5 : 66- 7 1 ( 1980 ) .

3 1 ) B l ank , J . H . Act i on of soap on s k i n . Arch . Derm . Syph . 39 : 8 1 1 -824

( 1 939 ) .

32 ) Bj ornberg , A . S k i n reactions to primary i rr i tants i n pati ents wi th

handeczema . Thes i s , Oscar I sacsons Tryckeri AB Goterborg , Sweden

{ 1963 ) .

33 ) Czerwi n s ka- D i hm , I . , Rudzk i , E . S k i n reacti ons to pr imary i rri tants .

Contact Dermat i t i s 7 : 3 1 5 -3 19 ( 1981 ) .

34 ) Coenraads , P . J . , B l eumi nk , E . , Nate r , J . P . Suscept i b i l i ty to prima ry

i rr i tants . Contact Dermati t i s 1 : 377-381 ( 19 75 ) .

3 5 ) Schne i der , W . Experi mentel l e Untersuchungen zur Frage der Rei n i gung ,

Pfl ege und externe Therap i e der Haut . Derm . Wschr . 1 52 : 505- 5 14

( 1965 ) .

36 ) Schne i der , W . , Tron n i e r , H . , Wagner , H . Rei n i gung und Pfl ege der Haut

im Beruf unter besonderen BerUck s i chti gung der experimentel l en u nd

prakt i s chen PrUfverfahren . I n : Dermatol ogi e und Venereol ogi e , Vol I / 2 ,

pp 1 043- 1070 ( 1962 ) Ed i tors : H . A . Gottron , W . Schonfel d . Georg Th i eme

Verl ag , Stuttgart .

141

CHAPTER 8

SUMMARY AND CONCLUS I ONS

SAMENVATTI NG EN CONCLUS I ES

1 42

Summary and conc l u s i ons .

I n t h i s thes i s , the resu l ts of a seri es of i nvestigat i ons i nto the

barri er funct ion of human s k i n are pres ented . I n these i nves t i gat i ons ,

the barr i er functi on was asses sed by water vapour l os s measu rements of

the s k i n u s i ng a method based on grad i ent e st ima t i on .

I n the fi rst chapter , a theoreti cal essay i s prov i ded based on a rev i ew

of the l i terature on the l ocal i za t i on , b i ochemi ca l compos i t i on and phy­

s i cal properti es of the s k i n barri er wi th spec i a l reference to the wa­

ter barri e r .

T h e importance o f an u n impa i red barr i er for prevent ion o f damage to the

v i ab l e l ayers of the s k i n and the pos s i b l e rol e of barr i er function de­

f i c i ency in the devel opment of chroni c i rr i tant contact dermat i t i s i s

d i scus sed . On the bas i s of the l i terature , i t i s concl uded that wi thout

penetrat i on through the horny l ayer i n deeper l ayers of the s k i n poten­

t i a l i rr i tant factors wi l l not g i ve r i s e to tox i c effects i n the s k i n .

The appl i cati on of the method of water vapour l os s meas urements to

a s sess barr ier impa i rment i s worked out and a s urvey of the most con­

found i ng vari abl es i s g i ven . The d i fferent methods of measurement of

water vapour l os s a re d i s cussed and compared wi th the method of g rad i ent

estimat i on . Measurement pri nci p l es and the accuracy of t he method of

gradi ent estimation are d i scussed .

I n Chapter 2 , t he method for asses s i ng the i nfl uence of substances on

the s k i n barri er for water u sed i n the seri es of i nvesti gati ons presen­

ted i n more detai l . The chamber techni que a s u sed to expose the s k i n to

the test substances and the method of measurement are e l aborated . I n

the s tudy presented i n Chapter 2 , the fol l ow i ng s u rface act i ve compounds

and contro l s were tested ( a l l i n d i s t i l l ed water ) :

sod i um l auryl s u l fate ani on i c s urfactant ( pH 7 . 3 )

sod i um l aurate a n i on i c s urfactant ( pH 9 . 2 )

pol ysorbate-60 non i o n i c s urfactant ( pH 3 . 8 )

cocobeta i ne amphoteri c s urfactant ( pH 5 . 2 )

d i st i l l ed water control ( pH 5 . 6 )

NaCl 0 . 9% control ( pH 6 . 7 )

143

Al l tes ted substances as assayed on the vol ar s i de of the forearm i n a

panel of heal thy vol unteers caused a s i gn i f i cant mean i ncrea se i n water

vapour l oss as compared wi th that of unexposed s k i n . D i s t i l l ed water

i nfl uenced the water barr i er of the s k i n to a greater extent than d i d

D . 9% NaCl i n d i s ti l l ed water .

Di vergent i ntra- en i nters ubject patterns of water vapour l oss data

were observed sugges t i ng each i nd i v i dual a s havi ng h i s own patterns of

suscepti b i l i ty to barr i er functi on d i s turbance .

The mean scores for the water vapour l oss measurements were compared

wi th those cal cul ated from the resu l ts of a ' v i sual scori ng system ' :

Erythema 1 + , s l i ght redness , s potty or d i ffuse ; 2+ , moderate redness ;

3+ , i ntense redness ; 4+ , fi ery red wi th edema .

Sca l i ng 1+ , fi ne ; 2+ , moderate ; 3+ , severe wi th l arge fl akes .

F i s sur i ng : 1+ , f i ne cracks ; 2+ , s i ng l e or mu l t i p l e broader fi ssures ;

3+ , wide cracks wi th hemorrhage or exudati on .

The systems proved to be h i gh ly correl ated for the substances tes ted ,

i mp ly i ng that the i rr i tancy of surfactants i s greatly dependent on the i r

effects o n the (water ) s k i n barr i e r .

T h e a im o f the study d i scussed i n Chapter 3 was the assessment by s k i n

water va pour l os s measurements o f s k i n barri er impa i rment caused by

surface acti ve compounds i n d i fferent eczema categori es and control

groups . For th i s purpose , unaffected s k i n of the vol ar s i de of the

forearm was exposed to the fol l owi ng substances ( a l l in a 2 g/v% i n

d i sti l l ed water ) :

sod i um 1 aura te a n i on i c ( pH = 9 . 2 )

sodi um stearate a n i on i c ( pH = 10 . 4 )

sodi um l auryl s u l fate a n i on i c ( pH 7 . 3 )

potas s i um soap II an ion i c ( pH 10 . 0 )

cocobetai ne amphoteri c ( pH 5 . 2 )

ceteareth-12 non i on i c ( pH 6 . 4 )

cocami dopropyl beta i ne amphoteri c ( pH 6 . 0 )

pol ysorbate-GO non i on i c ( pH 3 . 8 )

II ) Potass i um sa l t of coconut- and r i c i nu s o i l .

The group of pati ents wi th eczema as a who l e reacted more severely to

144

the test substances . T h i s was ch i ef ly the resu l t of reacti ons of the

subgroup of pati ents wi th atopi c dermati ti s . The atop i c pati ents reacted

more severel y to the test substances , espec i a l l y to the syntheti c deter­

gents ( arti fi c i a l ly bui l t up surface acti ve compounds out of coa l or mi ­

neral oi l ) . The a l ka l i ne soaps ( carboxyl ates of an ima l or veg eta b l e

oi l s ) were tol erated rel ati ve ly wel l i n t h i s g roup , confi rm ing t h e re­

su l ts of other stud ies . In the subgroup of pati ents wi th i rr i tant con­

tact dermati ti s , i t was not poss i b l e to demon strate a more severe reac­

t i on as determi ned by s k i n water vapour l oss in compar i son wi th the

control groups , sugges t i ng a l i mi ted rol e of a c onsti tuti onal vul nera­

b i l i ty to barr ier functi on d i s turbances in t h i s grou p .

I n Chapter 4 , a study compari ng t h e effects o n t h e barr i er functi on of

the s k i n of a poss i b l e a l l ergen ( n i ckel su l fate ) i n a concentrati on not

norma l l y g i ven r i se to a v i s i b l e i rri tant reacti on and th ree test sub­

s tances wi th moderate ( v i s i b l e ) tox i c effects in the concentrati ons em­

p l oyed i s presented . The fol l owi ng test substances ( a l l in d i st i l l ed

water ) were appl i ed to the vo l ar s i de of the forearm :

n i ckel su l fate 5 g/v% { p H 5 . 4 )

sod i um l au ryl su l fate 5 g/v% ( pH 7 . 3 )

d i methyl su l fox i de 50 g/v% ( pH 7 . 1 )

phenol 5 g/v% ( pH 6 . 2 )

Ba rri er funct i on d i sturbances a s as sessed by water vapour l os s were a l s o

rel a ted to macroscopi cal l y v i s i b l e changes ( ' v i sual scoring system ' ) .

The test s i tes exposed to n i c ke l su l fate were a l so read for a l l erg i c

react i ons accord i ng to a current method . The i nf l uence of the d i fferent

grades of a l l erg i c reacti ons on water vapour l os s was i nvesti gated . The

exposures were done in a g roup of persons wi th a h i s tory of pos i t i ve

a l l erg i c patch test reacti ons to n i c ke l su l fate and a group of persons

wi thout any s k i n d i sease or known a l l ergy . Genera l l y , a l l test sub­

s tances caused an i ncrease in s k i n water vapour l os s in compari son wi th

a control ( d i s ti l l ed wate r ) . The correl a t i on between the s treng th of the

erythematous reacti on and the i n crease of water vapour l oss of the expo­

s ed s k i n s i tes vari ed cons i derab ly among the app l i ed substances . Al l er­

g i c react i ons , es peci a l l y the strong reacti ons , were shown to be abl e to

145

effect the water barr i er of the s k i n .

I t was concl uded that a substance may damage the horny l ayer i n severa l

ways : 1 ) d i rect l y by i ts phys i cochem i ca l properties ( i nteract i on wi th

horny l ayer components ) ;

2 ) i nd i rectl y , after permeation through the horny l ayer , by i ts

effect ( tox i c and/or a l l erg i c ) on the deeper v i ab l e l ayers of

the s k i n . Th i s may secondari ly resu l t i n a def i c i ent horny

l ayer format ion .

Both d i rect and i nd i rect effects may d i s tu rb the barr i er functi on on the

s k i n . It i s a l so concl uded that the extent of the horny l ayer barr i er

funct ion d i sturbance as caused by a substance may run para l l e l to the

extent of the v i s i b l e i nfl ammatory reacti ons of the deeper l ayers of the

s k i n .

Thi s , h owever , i s not a l ways the case , espec i a l l y not i f the effects are

eva l ua ted on ly once , because barr i er i mpai rment and repa i r of the horny

l ayer wi l l fo l l ow another t ime course than the v i s i b l e i nfl ammatory re­

act i on of deeper l ayers of the s k i n .

The resu l ts of a l ong i tud i nal i nvesti gati on of the effect of repeated

s k i n exposures to surface acti ve compounds on the water barr i er are pre­

sented i n Chapter 5 and compared wi th macro scop i ca l ly v i s i b l e changes

( ' v i sual scori ng system ' ) . The fol l owi ng propri etary products were tes ted

i n a 1 g/v% i n d i sti l l ed water on the vol ar s i de of the r i ght arm :

Zwi tsal baby soap ( pH 10 . 6 )

Su l foderm soap ( pH 5 . 9 )

Neutrogena soap ( pH = 9 . 8 )

Lactacyd soap ( pH 3 . 8 )

On the vol ar s i de of the l eft arm were tes ted i n a 0 . 5 g/v% i n d i sti l l ed

water the fol l owi ng surfactants :

cocobetai ne ( pH 5 . 2 )

sod i um l aurate ( pH 9 . 3 )

sod i um l au ryl su l fate ( pH 7 . 3 ) pol ysorbate-60 ( pH 3 . 8 )

The effects of l ow concentrat ions of surface acti ve compounds ( i n a test

panel of hea l thy subjects ) proved to be cumu l ati ve and there was a

146

correspondence between the general pattern of water vapour l os s and the

macroscopi ca l ly occurri ng v i s i bl e changes . I t has conc l uded that re­

pea ted s k i n exposures to l ow concentrat i ons of surfactants may l ead to

i ncreased permeati on and may consequentl y faci l i tate the devel opment of

chron i c i rr i tant contact dermati ti s . Other factors such as faul ty i n­

fl ammatory control mechani sms , d i s turbance of homeostas i s of the v i a b l e

l ayers o f the epi derm i s and derm i s and accumul a t i on o f ( endogeneous )

anti gens and i rr i tants i n repeatedl y exposed s k i n s i tes may a l s o p l ay a

rol e i n caus i ng or mai nta i ni ng chron i c i rr i tant contact dermati ti s .

I n Chapter 6 , the method of s k i n water vapour l oss measurements i s u sed

to assess the subc l i n i ca l effects of l ow concentrati ons of substances

known as s trong i rr i tant i n h i g her concentrati ons . The fol l owi ng sub­

stances were appl i ed to c l i n i ca l l y unaffected s k i n of the vol a r s i de of

the forearm ( g/v% in d i s ti l l ed water ) :

sod i um l au ryl sul fate 2 g/v%

cocobeta i ne 2 g/v%

croton a l dehyde 0 . 75 g/v% and sod i um l au ryl su l fate

0 . 5 g/v%

d imethyl s u l fox i de 50 g/v%

phenol 5 g/v%

sod i um hydroxi de 1 g/v%

benzal koni um c h l or ide 0 . 2 g/v%

d i st i l l ed water

( pH 7 . 3 )

( pH 5 . 2 )

( pH 4 . 8 )

( pH 7 . 1 )

( pH 6 . 2 )

( pH 12 . 7 )

( pH 6 . 6 )

( pH 6 . 5 )

These test so l ut ions e l i c i ted only s l i ght macroscopi cal l y v i s i b l e re­

acti ons of the s ki n . The surface act i ve compounds ( sod i um l au ryl su l fate ,

cocobetai n e and the combi nati on of croton a l dehyde wi th sod i um l au ryl

su l fate ) , except for benza l kon i um chl ori de , i nc reased water vapour l os s

s i gn i fi cantly i n compari son wi th unexposed s ki n . D imethyl su l fox i de at

50% and 1 % sod i um hydrox i de a l so i ncreased sk in water vapour l os s s i gn i ­

f i cant ly . Phenol at 5% d i d not i nfl uence the barr i er functi on of the

s k i n for water .

I t was concl uded that i rr i tant substances i n l ow concentrat i on may have

a subcl i n i cal effect on s k i n barr i er functi on , a l though not a l l i rr i tant

substances produce th is effect .

147

I n the study of Chapter 7 , the effects of 13 propri etary soap and syn -

theti c detergen t bars on the water barri er funct i on of the s k i n was eva-

l uated . The fol l ow i ng products were tes ted on the vol a r s i de of the

forearm i n a panel of heal thy subjects :

Aveenoderm ( pH 5 . 4 ) Pa lmol i ve ( pH 10 . 6 )

C i da l ( pH 10 . 6 ) Sebamed ( pH 5 . 5 )

Johnson ' s babysoap ( pH 1 0 . 7 ) Sebapona ( pH 6 . 7 )

Lactacyd ( pH 3 . 8 ) Sporex ( pH 1 0 . 6 )

Lux ( pH 9 . 7 ) Su l foderm ( pH 5 . 9 )

Neutrogena ( pH 9 . 8 ) U n i cura ( pH 10 . 6 )

Zwi tsa l babysoap ( pH 10 . 6 )

Al l of the propri etary products were found to l ead to a s tati st i cal ly

s i gn i fi cant i ncrease i n wa ter vapour l os s a s compared wi th d i s t i l l ed wa ­

ter . Synthet i c detergent bars based on al kyl s u l fates had a rel a ti vely

greater effect on the s k i n ba rri er than d i d the other products . On the

whol e , however , the mean d i fferences between the products were smal l .

I t i s concl uded that d i fferences i n ' s k i n type ' probably a l so determ i ne

wh i ch products are wel l tol era ted .

The con s i derab l e var i a t i on i n wa ter vapour l os s data as observed i n the

stud i es d i scus sed in th i s t hes i s may hamper a - correct i n terpretat i on .

Partly th i s vari at ion can be expl a i ned by the i nfl uence of i n terven i ng

vari abl es l i ke , e . g . , sweati ng .

The i nfl uence of these vari abl es ( random vari ati on i s l i ke l y ) cou l d be

restri cted by compa r i ng mean s cores .

A s i ng l e person ' s i mpa i rment of s k i n barri e r functi on however , cou l d not

be assessed rel i abl y . Da ta about the suscept i bi l i ty of the i nd i v i dual

to barr i er functi on d i s turbances can probably on l y be obtai ned by keepi ng

the i nfl uence of ( random ) var i a t i on i n more narrow l i mi ts .

1 48

Samenvatt i ng en conc l u s i e s .

I n d i t proefschri ft z i j n d e resul taten gebund e l d van een aantal onder­

zoeken naar de barri erefuncti e van mensel i j ke h u i d tegen schade l i j ke

i nv l oeden u i t de omgev i nq .

I n deze studi es werd de barri erefunct i e van de mensel i j ke hu i d onder­

zocht met behu l p van waterdampverl i esmet i ngen . De met i ngen werden ver­

ri cht vol gens een methode gebaseerd op het meten van de rel ati eve

vocht i ghe id op twee afstanden van de hu i d .

I n het eerste hoofd stuk wordt een theoreti sche verhandel i ng gegeven

over de l oka l i sati e , b i ochemi sche samenstel l i ng en fys i sche ei genschap­

pen van de hu i dbarri ere . Deze verhandel i ng , toegesp i tst op de h u i d ­

barri ere voor waterdampverl i es , i s gebaseerd op l i teratuuronderzoek .

Het bel ang van een onbeschad i gde h u i dbarri ere voor de preventi e van be­

schadi g i ng van d i epere l agen van de hu i d en de mogel i j ke rol van stoor­

n i ssen van de barri erefuncti e b i j het ontstaan van het orthoerg i sch con­

tact eczeem worden bes proken .

Op bas i s van l i tera tuuronderzoek wordt geconc l udeerd dat zonder pe�etra­

t i e door de hoornl aag i n de d i epere l agen van de hui d potenti ee l bescha­

d i gende fa ktoren geen aan l e i d i ng geven tot tox i sche effekten in de hu i d .

De toepass i ng van de waterdampverl i esmeti ngen a l s methode om beschad i ­

g i ng van d e h u i dbarri ere o p te sporen wordt u i tgewerkt en een overz i cl tt

van de var i a bel en , d i e de meti n g kunnen beinv l oeden , wordt gegeven .

Tevens worden de versch i l l ende methoden om het waterdampverl i es te me­

ten bes proken en vergel eken met de i n deze s tud i e toegepaste method i ek .

De meetpr i nc i pes en de nauwkeur i ghe i d van het i n deze s tud i e gebru i kte

i ns trument worden besproken .

I n hoofdstuk 2 wordt de methode besproken om met behu l p van waterdamp

verl i esmeti ngen van de hu i d de i nv l oed van chem i sche s toffen op de h u i d ­

barri ere t e meten .

De kamertechn i e k , zoa l s i n de s tud i es van d i t proefschri ft gebru i kt om

de hu i d aan de chem i sche s toffen b l oat te s tel l en , en de meetprocedure

worden u i tgewerkt .

I n de s tud i e van d i t hoofdstuk werden de vol gende wasakti eve s toffen en

149

control e v l oei stoffen getest ( i n gedest i l l eerd water ) :

natri uml auryl su l faat an i onogene wasakti eve stof ( pH 7 . 3 )

natri uml auraat an i onogene wa sakti eve stof ( pH 9 . 2 )

pol ysorbaat-60 n i et- i onogene wasakti eve stof ( pH 3 . 8 )

cocobeta i ne amfotere wa sakti eve stof ( pH 5 . 2 )

gedes ti l l eerd water contro l e ( pH 5 . 6 )

NaCl 0 . 9% control e ( pH 6 . 7 )

Al l e s toffen werden getes t op de vol a i re z ijde van de onderarm . I n een

groep van gezonde vri jwi l l i gers veroorzaakten a l l e versch i l l ende v l oe i ­

s toffen een s i gn i fi cante toename i n waterdampverl i es i n vergel i j k i ng met

n i et geexponeerde hu i d .

Gedest i l l eerd water veroorzaakte een gemi dde l d grotere toename i n water­

dampverl i es dan een opl os s i ng met 0 . 9% NaCl .

Zowel sprei d i ng tussen de getes te stoffen a l s tussen de proefpersonen

werd waargenomen . Het sterk wi ssel ende patroon in waterdampverl i es w i j s t

erop d a t i eder i nd i v i du een ei gen gevoel i ghe idspatroon voor stoorn i ssen

van de barri erefuncti e heeft .

De gemi ddel de scores van de waterdampverl i esmeti ngen werden vergel eken

met de scores berekend van de resu l taten van een sys teem ter eva l uat ie

van de z i chtbare afwi j k i ngen ( ' v i sual scor i n g system ' ) :

Erytheem 1+ , l i chte roodhei d , pl aatsel i j k of d i ffuus ; 2+ , mat i ge

roodhei d ; 3+, i ntense roodhei d ; 4+ , fel l e roodhe i d met

oedeem.

Sch i l feri ng : 1+ , l i chte schi l fer ing ; 2+ , matige schi l feri ng ; 3+ , ern­

st i ge sch i l feri ng .

Barstj es 1+ , fi j ne barstjes ; 2+ , een of meerdere d i epere barstjes ;

3+ , w i jdere barstj es met b l oed i ngen of exsudaat .

De twee systemen ter eva l uat i e van het effect van d e geteste v l oe i stof-

fen hadden een hoge correl ati e , hetgeen erop du idt dat de schadel i j ke

werk i n g op de hui d van wasakti eve stoffen voor een groat gedee l te wordt

bepaal d door het effekt van deze stoffen op de hui dbarri ere .

Het doel van de stud i e , bes pro ken i n hoofdstuk 3 , was het meten van de

h u i dbeschad i g i ng met behu l p van waterdampverl i esmetingen door wasakti eve

stoffen i n verschi l l ende eczeemcategori een en control egroepen . H i ervoor

1 50

werd onaangedane h u i d van de vol a i re z i jde van de onderarm b l ootgestel d

a an de vol gende chemi sche stoffen ( 2 g/v% i n gedesti l l eerd water ) :

natri uml auraat an i onogeen ( pH 9 . 2 )

natri umstearaat an i onogeen ( pH 10 . 4 )

natri uml auryl s u l faat ani onogeen ( pH 7 . 3 )

ka l i umzeep* ani onogeen ( pH 10 . 0 )

cocobeta i ne amfoteer ( pH = 5 . 2 )

ceteareth- 12 n i et i onogeen ( pH 6 . 4 )

cocami dopropyl beta i ne amfoteer ( pH 6 . 0 )

pol ysorbaat-60 n i et i onogeen ( pH 3 . 8 )

* ) kal i umzout van cocos - e n wondero l i e .

De groep pati enten met eczeem reageerden i n z i j n geheel s terker op de

testv l oe i s toffen . D i t werd hoofdzakel i j k veroorzaakt door de resu l taten

van de subg roep met const i tut i oneel eczeem . Deze pati enten reageerden

heft i ger op de geteste v l oei s toffen , met name op de syntheti s che deter­

genti a ( kunstmati g berei de wasakt i eve s toffen u i t s teenkool of mi nera l e

o l i e ) . D e a l kal i sche zepen ( ca rboxy l aten van d i erl i j ke o f p l antaard i ge

oorsprong ) werden rel ati ef goed verdragen i n deze g roep , hetgeen de

resu l taten van andere stud i es bevesti gen .

I n de subgroep van pati enten met orthoergi sch contact eczeem kon een

hefti ger reacti e ( gemeten met waterdampverl i es ) n i et worden vastgeste ld

i n vergel i j k i ng met de contro l egroepen . Deze bev i nd i ngen s uggereren een

beperkte rol van een consti tutione l e kwetsbaarh e i d voor barri erefuncti e­

stoorni ssen in deze g roep pati enten .

I n hoofdstuk 4 wordt een s tud i e besproken , waar i n de effecten van een

a l l ergeen ( n i kkel s u l faat ) i n een concentrati e , d i e normal i ter geen

z i chtbare beschadi g i ng van de hu i d veroorzaakt en dri e chemi sche s tof­

fen , d i e in de toegepaste concentrat i e mat i ge ( z i chtbare ) toxi sche

effecten veroorzaken , werden verge l e ken wat betreft de effecten op de

barri erefuncti e van de hui d . De vol gende testvl oei s toffen werden op de

huid van de vol a i re z i jde van de onderarm ( i n gedesti l l eerd water ) ge­

pl akt :

1 5 1

n i kkel su l faat 5 g/v% ( pH 5 . 4 )

natr i um lauryl su l faat 5 g/v% ( pH 7 . 3 )

d i methyl su l fox i de 50 g/v% ( pH 7 . 1 )

phenol 5 g/v% ( pH 6 . 2 )

De barri erefuncti es toorn i s sen ( gemeten met waterdampverl i esmethode ) wer-

den oak gerel ateerd aan de macroscopi sch z i chtba re afwi j k i ngen van de

hu i d ( vol gens het ' v i s ual scori ng system ' ) . De hu i d geexponeerd aan

n i k ke l s u l faat werd oak afgel ezen voor a l l ergi sche reacti es vol gens een

gang bare method i e k . De i nv l oed van de ( versch i l l ende ) grader i ngen van

de a l l erg i sche reacti es op het waterdampverl i es werd onderzoch t .

De b l ootstel l i ng a a n de testvl oei stoffen werd verri cht i n een groep pa­

t i enten met pos i t i eve l apj es proeven voor n i kkel su l faat en een groep per­

sonen zonder hui dzi ekte of ( bekende ) a l l erg i e .

I n het a l gemeen veroorzaakten a l l e testvl oe i stoffen een toename i n wa­

terdampverl i es i n vergel i j k i ng met de contro l e ( gedesti l l eerd water ) .

De correl ati e tussen de ernst van het erytheem en de toename van het

waterdampverl i es van de aan de chem i sche s toffen b l ootgestel de hui d va­

ri eerde aanz i en l i j k voor de verschi l l ende s toffen .

Al l erg i sche react i es , met name de heft i ge react i es , hadden i n een aantal

geva l l en een aanz i en l i j k effect op het waterdampverl i es van de hu i d .

Er werd geconc l udeerd dat een chemi sche stof de hoorn l aag kan beschad i ­

gen op versch i l l ende mani eren :

1 ) Di rekt door z i j n fys i cochemi sche ei genschappen ( i nteract i e met hoorn­

l aag bestanddel en ) .

2 ) I nd i rekt , na permeat i e van de hoornl aag , door z i j n· effecten ( toxi sch

en/of a l l erg i sch ) op de d i epere l agen van de hu i d . D i t kan secunda i r

tot een def i c i ente hoorn l aagforma t i e l e i den .

Bei de effecten kunnen aan l e i d i ng geven tot verstori ng van de barri ere­

functi e van de hui d .

Er werd eveneens geconc l udeerd dat de omvang van d e stoorn i s van de

barri erefuncti e van de hoorn l aag , veroorzaakt door chemi sche stoffen ,

overeen kan komen met de omvang van de z i chtbare ontsteki ngsreact i es

van de d i epere l agen van de hu i d . D i t i s echter n i et a l t i j d het ge­

va l , met name n i et i ndi en de effecten eenma l i g worden geeval ueerd ,

1 52

omdat beschad i g i ng en herstel van de hoorn l aag en de di epere l agen van

de hui d een ei gen verl oop in de t i j d kunnen hebben .

I n hoofdstuk 5 worden de resu l taten van een l ongi tudi naal onderzoek naar

het effect van herhaa l de b l ootstel l i ng van de hu i d aan wasakti eve stof­

fen op de barri ere voor waterdampverl i es besproken en vergel eken met de

macroscopi sch z i c htbare veranderi ngen ( ' v i sua l scori ng system ' ) .

De vol gende merkprodukten werden getest i n 1 g/v% i n gedesti l l eerd water

op de vol a i re z i j de van de rechterarm :

Zwi tsal babyzeep ( pH

Su l foderm zeep ( pH

Neutrogena zeep ( pH

Lactacyd zeep ( pH

10 . 6 )

5 . 9 )

9 . 8 )

3 . 8 )

Op de vol a i re z i jde van de l i nkera rm werden was akti eve chemi cal i en ge­

test in 0 . 5 g/v% in gedes ti l l eerd wa ter :

cocobeta i ne ( pH 5 . 2 )

natri uml auraat

natr i um lauryl s u l faat

pol ysorbaa t-60

( pH

( pH

( pH

9 . 3 )

7 . 3 )

3 . 8 )

De effecten van d e toegepaste l age concentrati es was akti eve stof bl eken

in de groep van geexponeerde vri jwi l l i gers een cumu l a t i ef effect te

hebben op de hu idbarri ere . In het a l gemeen kwam het pa troon van het

waterdampverl i es overeen met het optreden van de macroscopi sch z i cht­

bare afwi j k i ngen . Er werd geconcl udeerd dat herhaa l de b l ootstel l i ng aan

l age concentrati e wasakti eve stof kan l ei den tot toename van de door­

gankel i j kh e i d en a l s gevol g daarvan het ontstaan van orthoerg i sch eczeem

kan bevorderen .

Andere factoren echter , zoa l s de onvol doende beteugel i ng van het ont­

stekingsproces , verstori ng van de homeostas i s i n de d i epere l agen van

de epi dermi s en derm i s en de accumu l at i e van ( endogene ) anti genen en

i rri tanti a in herhaa l del i j k b l ootgeste l de hu i d kunnen ook een rol

s pe l en in het veroorza ken en onderhouden van het orthoerg i sch contact

eczeem .

I n hoofdstuk 6 werd de methode van de waterdampverl i esmeti ngen toegepast

1 53

om het subkl i n i sche effect van l age concentrati es van chemi sche stoffen ,

i n hogere concentrati es s terk i rri terend voor de hu i d , te eva l ueren .

De vol gende chemi sche s toffen werden op n i e t-aangedane hu id van de vo­

l a i re z i jde van de onderarmen i n een groep van dermatol ogi sche pati enten

getes t ( g/v% in gedesti l l eerd water ) :

natri uml aury l su l faat 2 g/v%

cocobetai ne 2 g/v%

crotonal dehyde 0 . 7 5 g/v% en natri uml aury l s u l faat

0 . 5 g/v%

d imethyl s u l fox i de 50 g/v%

phenol 5 g/v%

natri umhydroxi de 1 g/v%

benza l kon i umch l ori de 0 . 2 g/v%

gedes ti l l eerd water

( pH =

( pH =

( pH

( pH

( pH :: ( pH

( pH =

( pH =

7 . 3 )

5 . 2 )

4 . 8 )

7 . 1 )

6 . 2 )

1 2 . 7 )

6 . 6 )

6 . 5 )

De testopl oss i ngen veroorzaa kten a l l een l i c hte macroscopi sch z i chtbare

afwi j ki ngen van de hu i d . De wasakti eve s toffen ( natri uml auryl su l faat ,

cocobeta i n e en de comb i nati e van crotona l dehyde met natri uml aury l su l ­

faat ) , beha l ve benza l kon i umch l ori de , veroorzaakten een s i gn i fi cante toe­

name i n vergel i j k i ng met n i et b l ootges tel de hui d . OMSO en NaOH veroor­

zaa kten eveneens een s i g n i fi cante toename van het waterdampverl i es .

Phenol 5% beinvl oedde de barri erefuncti e van de hu id voor het water­

dampverl i es n i et .

Er werd geconc l udeerd dat de i rri tanti a i n l age concentrati es een

subk l i n i sc h effect kunnen hebben op de barri erefuncti e van de hu i d ,

hoewel n i et a l l e i rr i tantia dat effect vertonen .

I n hoofdstuk 7 werd het effect van 13 commerci ee l verkr i jgbare s tu kjes

zeep op de waterbarri ere van de huid bestudeerd . De vol gende produ kten

werden getest i n een groep gezonde vri jwi l l i gers op de vol a i re z i j de

van de onderarm :

Aveenoderm ( pH 5 . 4 ) Neutrogena ( pH = 9 . 8 )

C i da l ( pH 10 . 6 ) Pa l mo l i ve ( pH = 10 . 6 )

Johnson ' s babyzeep ( pH 1 0 . 7 ) Sebamed ( pH = 5 . 5 )

Lactacyd ( pH :: 3 . 8 ) Sebapona ( pH = 6 . 7 )

Lux ( pH 9 . 7 ) S porex ( pH = 10 . 6 )

1 54

Sul foderm

Uni cura

( pH 5 . 6 )

( pH 10 . 6 )

Zwi tsa l babyzeep { pH 10 . 6 )

Al l e produ kten veroorzaa kten een s i gn i fi cante toename van het waterdamp­

verl i es i n vergel i j k i ng met gedes ti l l eerd water . Synthet i s che zepen ,

gebaseerd op a l ky l su l faten , hadden een rel a t i ef groter effect op de

hu i dbarri �re dan de andere produkten . In het g eheel wa ren de gemi dde l de

verschi l l en echter ger i ng en mees ta l n i et-s i g n i fi cant . Er werd gecon c l u ­

deerd dat versch i l l en i n ' hu i dtype ' waarsch i j n l i j k eveneens bepal en wel k

produkt het best door de hu id wordt verdragen .

De aan z i en l i j ke spre i d i n g zoa l s waargenomen i n de resul taten van de wa­

terdampverl i esmeti ngen i n de bes proken s tudi es bemoe i l i j ken een j u i s te

i nterpretat i e . Voor een gedeel te kan deze spre i d i ng worden verkl aard

door de i nv l oed van s torende factoren zoa l s b . v . zweten .

De i nv l oed van deze storende vari a bel en (wi l l ekeuri ge sprei d i ng i s aan­

n emel i j k ) kon worden beperkt door gemi ddel de scores te vergel i j ken .

De beschad i g i ng van de hu idba rri �re b i j een i nd i v i du kon echter n i et be­

trouwbaa r worden bepaa l d . Gegevens over i nd i v i duel e gevoel i ghei d voor

beschad i g i ng van de hu i dbarri ere kunnen waarsch i j n l i j k a l l een worden ver­

kregen i nd i en de i nv l oed van de (wi l l ekeuri ge ) spre i d i ng meer wordt be­

perkt .

155

EXTERNAL. (EJIMRON�ENTAL)

Sll�UU

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l ���UNE RESPONSE

l HORNY LAYER BMRIER

� FUNCTlON OISRIRBANCE

l T AUERGIC (CHRONIC OR ACUTE)

CYTOTOXIC EFTECTS CONTACT OERWAnns

UPON THE VIABLE AO.t.PTATlON AND

LAYERS OF' THE SKIN fE- � IRRITANT (CHRONIC OR ACliTE) ftEGENEPtAT10N

! i CONTACT 0£RMAnns

CONST1RIT10NAL. F'ACTORS

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PERSISTENT INfl....I.MWATORY crus

ACTlVAOON OF' INfl....I.MMATORY

Crus AND/OR HUMORAL F'ACTORS

Hypothet i ca l d i agram of the pathogenes i s of horny l ayer impai rment

and the rol e of barrier functi on d i sturbance i n the et i o l ogy of

i rri tant and a l l erg i c contact dermat i t i s .

1 56

Dankwoord/Acknowl edgement

Voor de hu l p , d i e i k heb verkregen bij het tot stand brengen van d i t

proefschri ft ben i k d e vol gende personen b i j zonder dankbaar :

- Dr . J . P . Nater , d i e het m i j mogel i j k maakte en m i j stimul eerde om het

onderzoek te verr i chten en onder wi ens d i rekte begel e id i ng de u i t­

voer i ng en het op schri ft stel l en p l aatsvond .

- Prof . D r . E . B l eumi n k , d i e m i j waardevol l e opmerki ngen verschafte om­

trent opzet , u i tvoer i ng en het op schr ift stel l en van d i t proefs chri ft .

- Prof . Dr . A . H . Kl okke , i n wi ens k l i n i e k het onderzoek pl aats kon v i n­

den .

Dr . P . J . Coenraads , d i e m i j i nwijdde op het gebi ed van de s tat i s t i ek

en computerprogrammatuur en met wi e i k zeer vruchtbare d i scuss i es had

omtrent opzet en u i tvoer i ng van het onderzoek .

- Mevr . A . Datema , d i e met veel i nzet het typewerk verzorgde .

- Dhr . A . J . Kl oosterhu i s , d i e het tekenwerk verzorgde en dhr . D . C . D i j k ,

d i e de foto ' s vervaard i gde .

- Mev r . T . Woes t , d i e hu l p verl eende b i j het onderzoek en

Dr. M . C . J . M . de Jong , d i e theoreti sche ondersteu n i ng verl eende .

- De col l egae Drs . M . C . Cri j ns , Drs . M . H . Kru i s -de Vri es en

dhr . B. Boorsma , d i e ass i s teerden b i j het onderzoek .

- Drs . V . F i d l er , d i e waardevol l e advi ezen verstrekte met betrekki ng tot

de toegepaste s tati s t i e k .

- Dr . A . C . Ford , P h D , who rev i ewed the engl i s h .

- Al l e proefpersonen , d i e z i ch beschi kbaar s te l den voor het onderzoek .

- Col l ega Drs . H . Lanti nga , met wi e i k pretti g h e b samengewerkt .

- Joke en Thi j s .

1 5 7