frequent lancing for monitoring blood glucose may cause skin changes

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Introduction Patients with diabetes who frequently monitor glucose in skin blood may develop discolouring and thickening of the skin at the lancing sites. These changes are a minor consequence of diabetes management and cannot be compared to the major threats of dia- betic organ disease. Nevertheless, they are annoying for the person affected as they make blood sam- pling more difficult and are cosmeti- cally unpleasant. This study exam- ines, in a group of people with diabetes, frequency and type of mor- phological skin changes following frequent lancing. Furthermore, it looks for factors favouring the occur- rence of these changes. Methods Members of a German diabetes self- help group (Die Insuliner) attending their annual meeting were examined for skin changes occurring at the fin- gertips or at alternative lancing sites. Ninety-three participants (>90% of the group) volunteered to participate in this study, of whom five had type 2 diabetes and the others type 1 dia- betes. Sixty of them were female, 33 male; the average age was 45 years (range 13–72 years) and the average duration of diabetes 24 years (range 2–46 years). First, all individuals were asked for information about their lancing habits (frequency of blood sampling, actually used and preferred lancing sites, pressure of the lancing device against the skin), lancing equipment (type of lancing device, lancing depth, repeated use of the same lancet), and side effects of lanc- ing (pain, oozing, inflammation). Then all fingertips and alternative lancing sites were checked by visual and tactile examination, and all skin changes were noted. Skin thickening at the lancing sites with respect to cor- responding normal skin was divided up into four classes (none, slight, moderate, severe). Finally, partici- pants were asked about tobacco con- sumption and whether or not they were prone to cold fingers. The average lancing frequency for each lancing site was estimated from the data of lancing frequency, used lancing sites and preferred lancing sites. In order to analyse a possible relationship between lanc- ing frequency and severity of skin changes, the finger data were arranged in a table of four lancing frequencies (0.5/day, >0.5–1.0/day, >1.0–1.5/day, >1.5/day), and three severities (none, slight, moderate/ severe) which were subjected to the Chi-square test. The statistics overes- timated the evidence because more than one lancing site of an individ- ual entered the analysis. Results The majority of people used the fin- gertips for blood sampling; only a few used the thenar (n=3) and the hypothenar (n=5) eminence of the palm, or the earlobe (n=2). On aver- age, six sites (range 1–10 sites) were regularly lanced by an individual. The most frequently used fingers were the middle, ring and little fin- gers (Figure 1), and the distal tips were the preferred lancing sites rather than the sides of the tactile ele- vations. Skin areas of the arm or of other sites were not regularly used, although several individuals had tried to measure glucose in blood from these sites but had given up this prac- tice because they thought glucose values deviated from those in finger- tip blood (Jungheim et al. 1 provide more information on this problem). Within the whole group, the average lancing frequency was 5.8/day (range 2.5–11); lancing frequency at one site ranged from 0.2–5 lancings/day. The average lancing frequency of the thumb and index finger was between 0.6 and 0.7/day; lancing frequency of the middle, ring and little fingers was between 0.9 and 1.1/day. One and the same lancet was used on average for 223 lancings (median 91, range 1 to >3000). Nearly 80% of the individ- uals used lancing devices with several easily adjustable depth settings. Only a few used freehand cannulae (n=6) or lancets (n=2). Most individuals applied the lancing device with too little pressure on the skin and they used depth settings that gave approx- imately two-thirds of the possible lancet protrusion (1.5–2.0mm). Pract Diab Int June 2006 Vol. 23 No. 5 Copyright © 2006 John Wiley & Sons, Ltd. 207 Frequent lancing for monitoring blood glucose may cause skin changes H Fruhstorfer* P RACTICE P OINT ABSTRACT Fingertips and alternative lancing sites were examined for skin changes in 93 people with diabetes, regularly checking blood glucose. In all, 60 individuals had a thickened skin at one or more lancing spots. Mainly fingertips and earlobes were affected whereas the thenar and hypothenar were free from these changes. There is a clear positive relationship between lancing frequency and skin changes which is possibly influenced by individual disposition. The observed relationship suggests the way in which to avoid skin changes: as many lancing spots as possible should be alternately used, avoiding lancing a given spot more often than once every other day. Copyright © 2006 John Wiley & Sons, Ltd. Practical Diabetes Int 2006; 23(5): 207–209 KEY WORDS fingertip lancing; skin blood; glucose measurement; skin changes Heinrich Fruhstorfer, MD, Former Professor of Physiology, Institute of Physiology, University of Marburg, Germany Correspondence to: Dr H Fruhstorfer, Ketzerbach 47, D-35037 Marburg, Germany; e-mail: [email protected] Received: 8 March 2004 Accepted in revised form: 17 December 2004

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IntroductionPatients with diabetes who frequentlymonitor glucose in skin blood maydevelop discolouring and thickeningof the skin at the lancing sites. Thesechanges are a minor consequence ofdiabetes management and cannot becompared to the major threats of dia-betic organ disease. Nevertheless,they are annoying for the personaffected as they make blood sam-pling more difficult and are cosmeti-cally unpleasant. This study exam-ines, in a group of people with diabetes, frequency and type of mor-phological skin changes followingfrequent lancing. Furthermore, itlooks for factors favouring the occur-rence of these changes.

MethodsMembers of a German diabetes self-help group (Die Insuliner) attendingtheir annual meeting were examinedfor skin changes occurring at the fin-gertips or at alternative lancing sites.Ninety-three participants (>90% ofthe group) volunteered to participatein this study, of whom five had type 2diabetes and the others type 1 dia-betes. Sixty of them were female, 33male; the average age was 45 years(range 13–72 years) and the averageduration of diabetes 24 years (range2–46 years). First, all individuals wereasked for information about theirlancing habits (frequency of bloodsampling, actually used and preferredlancing sites, pressure of the lancingdevice against the skin), lancingequipment (type of lancing device,lancing depth, repeated use of thesame lancet), and side effects of lanc-ing (pain, oozing, inflammation).Then all fingertips and alternativelancing sites were checked by visualand tactile examination, and all skinchanges were noted. Skin thickening

at the lancing sites with respect to cor-responding normal skin was dividedup into four classes (none, slight,moderate, severe). Finally, partici-pants were asked about tobacco con-sumption and whether or not theywere prone to cold fingers.

The average lancing frequencyfor each lancing site was estimatedfrom the data of lancing frequency,used lancing sites and preferredlancing sites. In order to analyse apossible relationship between lanc-ing frequency and severity of skinchanges, the finger data werearranged in a table of four lancingfrequencies (≤0.5/day, >0.5–1.0/day,>1.0–1.5/day, >1.5/day), and threeseverities (none, slight, moderate/severe) which were subjected to theChi-square test. The statistics overes-timated the evidence because morethan one lancing site of an individ-ual entered the analysis.

ResultsThe majority of people used the fin-gertips for blood sampling; only a fewused the thenar (n=3) and thehypothenar (n=5) eminence of thepalm, or the earlobe (n=2). On aver-age, six sites (range 1–10 sites) wereregularly lanced by an individual.The most frequently used fingers

were the middle, ring and little fin-gers (Figure 1), and the distal tipswere the preferred lancing sitesrather than the sides of the tactile ele-vations. Skin areas of the arm or ofother sites were not regularly used,although several individuals had triedto measure glucose in blood fromthese sites but had given up this prac-tice because they thought glucose values deviated from those in finger-tip blood (Jungheim et al.1 providemore information on this problem).Within the whole group, the averagelancing frequency was 5.8/day (range2.5–11); lancing frequency at one siteranged from 0.2–5 lancings/day. Theaverage lancing frequency of thethumb and index finger was between0.6 and 0.7/day; lancing frequency ofthe middle, ring and little fingers wasbetween 0.9 and 1.1/day. One andthe same lancet was used on averagefor 223 lancings (median 91, range 1to >3000). Nearly 80% of the individ-uals used lancing devices with severaleasily adjustable depth settings. Onlya few used freehand cannulae (n=6)or lancets (n=2). Most individualsapplied the lancing device with toolittle pressure on the skin and theyused depth settings that gave approx-imately two-thirds of the possiblelancet protrusion (1.5–2.0mm).

Pract Diab Int June 2006 Vol. 23 No. 5 Copyright © 2006 John Wiley & Sons, Ltd. 207

Frequent lancing for monitoring bloodglucose may cause skin changesH Fruhstorfer*

PRACTICE POINT

ABSTRACTFingertips and alternative lancing sites were examined for skin changes in 93 people withdiabetes, regularly checking blood glucose. In all, 60 individuals had a thickened skin atone or more lancing spots. Mainly fingertips and earlobes were affected whereas thethenar and hypothenar were free from these changes. There is a clear positive relationshipbetween lancing frequency and skin changes which is possibly influenced by individualdisposition. The observed relationship suggests the way in which to avoid skin changes:as many lancing spots as possible should be alternately used, avoiding lancing a givenspot more often than once every other day. Copyright © 2006 John Wiley & Sons, Ltd.

Practical Diabetes Int 2006; 23(5): 207–209

KEY WORDSfingertip lancing; skin blood; glucose measurement; skin changes

Heinrich Fruhstorfer, MD, Former Professorof Physiology, Institute of Physiology,University of Marburg, Germany

Correspondence to: Dr H Fruhstorfer,Ketzerbach 47, D-35037 Marburg, Germany;e-mail: [email protected]

Received: 8 March 2004Accepted in revised form:17 December 2004

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Two-thirds of the examined indi-viduals had thickened skin at one ormore lancing sites (Figure 2); thiswas similar for men and women.Altogether 523 fingers were used forregular blood sampling and 24%, 6%and 2% of these showed slight, mod-erate and severe thickening, respec-tively (Figure 1). Often the skin atthe lancing sites was also rough andyellowish discoloured. Earlobes regu-larly lanced were markedly enlargedand thickened; they were, however,soft and the epidermis was not con-spicuously altered. On the fingertipsthere was a clear tendency for a grow-ing number of skin changes withincreasing lancing frequency (Figure3; Chi-square <0.0001); only 6% ofthe fingers lanced once every secondday or less often had a thickenedskin, whereas 69% of the fingerslanced more than 1.5 times per dayshowed skin changes. The thenarand hypothenar never had a thick-ened skin even if a site was used twiceper day and some fingers of the sameindividual had skin changes. Theoccurrence of skin changes differedinterindividually. In some individualsall lanced sites had a thickened skinalthough lancing frequency was oneper day or less. In others, only one ortwo of the lancing sites were alteredor all were normal despite their fre-quent use. There was no indicationthat the frequent use of the samelancet promoted the skin changesnor was there a conspicuous relation-ship with smoking habits or beingprone to cold fingers.

DiscussionThe results show that regular lancingof the fingertips for sampling skinblood results in thickened skin inmore than half of the individuals.These skin changes are the more frequent the higher the lancing fre-quency is at a given skin area.

At first glance the thickened skinresembles hyperkeratotic changes asa consequence of friction or otherpersisting mechanical strain of theskin. Examination of these changeswith optic coherence tomographysuggested, however, that the stratumcorneum is not involved and that thehypertrophic area seems to includeviable epidermis and/or dermis.2The apparently normal skin surface

208 Pract Diab Int June 2006 Vol. 23 No. 5 Copyright © 2006 John Wiley & Sons, Ltd.

PRACTICE POINT

Frequent lancing for monitoring blood glucose may cause skin changes

Figure 1. Frequency of skin thickening observed at the different fingers inpercentage of the fingers used for lancing. Shading indicates the degree ofthickening (light = severe, dark = slight); the figures below give the numberof fingers lanced on the right/left hand. The higher incidence of skinthickening in the middle, ring and little fingers is caused by a higher lancingfrequency of the fingers used

Figure 2. Photograph of severe skin thickening at the tips of the middle,ring and little fingers of the right hand; normal skin on the sides of the tactileelevations and on the index finger. Female person 44 years old; diabetessince 42 years; five to six controls/day lancing only the tips of the middle,ring and little fingers of both hands; corresponding skin changes on theother hand

Thumb Index finger Middle finger Ring finger Little finger (7/7) (19/20) (70/78) (78/86) (76/82)

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of the earlobes which were enlargedafter frequent lancing would supportthis assumption. Lancing also differsfrom frictional strain by repeatedlyinjuring a multitude of cells andnerve endings down to the subpapil-lary venous plexus3 and leavingblood within the punctured wound.Many of the injured cells and of theblood constituents release a multi-tude of mediators4 that activateimmunologic and repair processesfor defence and healing. In suscepti-ble individuals, an excessive activityof these processes may lead to hyper-trophy of the skin. Morphology willhave to show which layers are in factinvolved in this lancing-provokedskin thickening.

Skin thickening is annoying forthe patient as it makes blood sam-pling more difficult and gives an

unpleasant sensation of tension. Atthe fingertips these changes tend todisappear if an affected area is notused for blood sampling for alonger period. The enlargement ofthe earlobes, however, seems to bepermanent.

The best remedy for hyper-trophic skin changes is their preven-tion. As they are caused by frequentwounding, lancing frequency at onespot and wound size have to be min-imised. This can be accomplished bythe following measures.• Both sides of the tactile elevationsof all fingers should be alternatelylanced. Lancing of the very tips of thefingers is not recommended as theseareas are normally heavily used by tac-tile activity. If special lancing equip-ment required for the thenar andhypothenar (i.e. a dome-shaped cap

with a wider aperture) is available,these sites should be lanced too. • A lancing device with depth adjust-ment should be used at the lowestpossible depth setting and with afirm pressure against the skin toensure the preset lancing depth.• In order to minimise the puncturelesion, thin (0.3–0.4mm diameter)and sharp (sharpness diminisheswith use) lancets should be used,and the required blood volumeshould be obtained by gently milk-ing the finger.

Lancing the skin of the fingers as wellas that of the thenar and hypothenaris a safe method to obtain blood ofhigh quality for measuring glucose.Apart from the frequent thickeningof the skin and extremely rare complications (e.g. infection5 ornecrosis6), this method has noadverse side effects: even after yearsof lancing neither blood perfusion7

nor sensibility8 of the fingertips showany signs of deterioration.

References1. Jungheim K, Koschinsky T. Glucose

monitoring at the arm: Risky delays ofhypoglycemia and hyperglycemiadetection. Diabetes Care 2002; 25:956–960.

2. Fruhstorfer H, Abel U, Garthe C-D, etal. Thickness of stratum corneum ofthe volar fingertips. Clin Anat 2000; 13:429–433.

3. Fruhstorfer H, Müller T, Scheer E.Capillary blood sampling: how muchpain is necessary? Part 2: relationbetween penetration depth and punc-ture pain. Pract Diabetes Int 1995; 12:184–185.

4. Falabella AF, Falanga V. Wound heal-ing. In The Biology of the Skin. FreinkelRK, Woodley DT (eds). New York:Parthenon, 2001; 281–297.

5. Ryan EA, Miller J, Skyler JS. Finger sep-sis: possible complication of self moni-toring of blood glucose. BMJ 1983;286: 1614–1615.

6. Giannini O, Mayr M. Finger pricking.Lancet 2004; 364: 980.

7. de Graaff JC, Hemmes GJ, Bruin T, etal. Influence of repetitive finger punc-turing on skin perfusion and capillaryblood analysis in patients with dia-betes. Clin Chem 1999; 45: 2200–2206.

8. Weber B. Führt häufigeKapillarblutentnahme aus derFingerbeere zu Gefäß- undNervenschäden? Marburg: MarburgUniversity Medical Dissertation, 2001.

Pract Diab Int June 2006 Vol. 23 No. 5 Copyright © 2006 John Wiley & Sons, Ltd. 209

PRACTICE POINT

Frequent lancing for monitoring blood glucose may cause skin changes

Key points

• Two-thirds of the diabetic patients monitoring glucose in blood from thefingertips suffer from thickening and discolouring of the skin at one or morelancing sites

• The occurrence of these skin changes is related to lancing frequency at agiven spot

• Using the sides of the tactile elevations of all fingers and lancing a given spotless often than once every other day will help to avoid thickening of the skin

Figure 3. Frequency of skin thickening as a function of lancing frequency inpercentage of lanced fingers in that category. Shading indicates the degreeof thickening (severe, moderate, and slight) and the figures below give thenumber of observations in this category

≤0.5/day ≤1.0/day ≤1.5/day >1.5/dayn= 71 274 107 71

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