the usefulness of dermoscopy in canine pattern alopecia: a ... · results – dermoscopic ﬁndings...

The usefulness of dermoscopy in canine patternalopecia: a descriptive study

Giordana Zanna*, Paola Roccabianca†, Eric Zini*‡§, Sara Legnani*, Fabia Scarampella¶, SilvanaArrighi** and Antonella Tosti††

*Istituto Veterinario di Novara, S.P.9 Granozzo con Monticello, Novara 28060, Italy

†Department of Pathology, Hygiene and Veterinary Public Health, Universit�a degli studi di Milano, Via Celoria 10, Milan 20133, Italy

‡Department of Animal Medicine, Production and Health, Universit�a degli studi di Padova, Via 8 Febbraio 2, Padua 35122, Italy

§The Clinic for Small Animal Internal Medicine, University of Zurich, Winterthurerstrasse 260, Zurich 8057, Switzerland

¶Studio Dermatologico Veterinario, Via G. Sismondi 62, Milan 20133, Italy

**Laboratory of Anatomy and Confocal Microscopy, Department of Health, Animal Science and Food Safety, Universit�a degli studi di Milano, Via

Trentacoste 2, Milan 20134, Italy

††Department of Dermatology & Cutaneous Surgery, Miller School of Medicine, University of Miami, 1295 NW 14th Street K –M, Miami,

FL 33136, USA

Correspondence: Giordana Zanna, Istituto Veterinario di Novara, S.P.9 Granozzo con Monticello, Novara 28060, Italy.

E-mail: [email protected]

Background – Dermoscopic studies evaluating noninflammatory, nonpruritic progressive alopecia attributable to

pattern alopecia are currently unavailable.

Hypothesis/objectives – To evaluate the dermoscopic features observed in healthy skin of short coated dogs

and compare these findings with those observed in dogs affected by pattern alopecia diagnosed by clinical and

dermatopathological examination.

Animals – Thirty male and female, healthy, breed matched, young adult, short coated dogs (controls) and 30

male and female, young adult, short coated dogs affected by pattern alopecia.

Methods – Dermoscopy was performed with a Fotofinder II videodermoscope equipped with software that

allowed the measurement of structures visualized in magnified images (209–409–709). Skin biopsy samples

were obtained from the thorax and evaluated dermoscopically for dermoscopic–histological correlation in

affected dogs.

Results – Dermoscopic findings in canine pattern alopecia were hair shaft thinning, circle hairs and follicular ker-

atin plugs; in the affected sun exposed areas there was a honeycomb-like pattern of pigmentation. Arborizing red

lines reflecting vascularization were classified as a nonspecific finding because they were also common in

healthy dogs. Dermoscopic features correlated with histology for selected hair follicle abnormalities.

Conclusions and clinical importance – Although canine pattern alopecia is a visually striking disease, this study

supports the value of dermoscopy for clinical examination and also opens promising perspectives for the identifi-

cation of diagnostic dermoscopic patterns that may be useful for other skin disorders.

Introduction

Skin surface microscopy has been reported to date back

to 1663, when Johan Kolhaus first looked at nail fold

vessels with a microscope.1 Nevertheless, it was only

during the 20th Century that several diagnostic methods

were developed utilizing surface microscopy. Currently,

two techniques are used for in vivo diagnosis. The first

is dermoscopy, originally used to observe and diagnose

pigmented skin lesions such as melanocytic nevus and

melanoma; the second is trichoscopy of the hair and

scalp.2–8 Trichoscopy has been used to visualize normal

hairs and assess their number per follicular unit, to dis-

tinguish whether hair follicle openings are normal,

empty, fibrotic or containing biological material as hyper-

keratotic plugs, and to study the appearance of perifollic-

ular epidermis and cutaneous microvessels.9 Therefore,

trichoscopy has proved relevant in the differentiation

between cicatricial and noncicatricial alopecias. On the

one hand, as a large group of disorders characterized by

permanent destruction of hair follicles, cicatricial alopecia

shows trichoscopic features such as loss of follicular

ostia and presence of white patches corresponding to

fibrous tracts that mark extinct hair follicles.10 On the

other, in all noncicatricial alopecias, such as alopecia

areata and androgenetic alopecia (male and female pat-

tern alopecia), suggestive trichoscopic findings are repre-

sented by specific hair shaft and follicular opening

abnormalities.11–13

In spite of the widespread use in human medicine, to

date only a few studies on the application of dermoscopy

Accepted 22 April 2016

This article is based on a Supporting original Study presented at

the 8th World Congress of Veterinary Dermatology held May

2016 in Bordeaux, France.

Sources of funding: The study was supported by an ESVD

Research Grant.

Conflict of interest: No conflicts of interest have been declared

© 2016 ESVD and ACVD, Veterinary Dermatology, 28, 161–e34. 161

Vet Dermatol 2017; 28: 161–e34 DOI: 10.1111/vde.12359

have been documented in veterinary medicine; specifi-

cally in feline dermatology.14–16 Moreover, except for an

unpublished abstract regarding the dermoscopic features

in 35 dogs with juvenile-onset demodicosis and 35 breed-

and age-matched dogs,17 to the best of the authors’

knowledge there is no dermoscopic study of canine non-

inflammatory alopecia. Therefore, the purpose of this

study was two fold. The first aim was to evaluate dermo-

scopic features observed in short coated healthy dogs

and compare these findings with those observed in short

coated dogs affected by pattern alopecia diagnosed by

clinical and dermatopathological examination. The second

aim was to validate the use of dermoscopy using

histopathology as a reference standard in order to gener-

ate dermoscopic criteria that would be useful for the diag-

nosis of pattern alopecia.

Material and methods

Study populationA population of 30 healthy, short coated dogs was matched with 30

short coated dogs referred for noninflammatory, nonpruritic progres-

sive alopecia attributable to pattern alopecia. Details about both

groups are presented in Table 1.

Dogs were owned by dog breeders or clients; informed owner

consent was obtained prior to any procedure. Dogs were

selected on the basis of the following criteria: (i) no other clinical

abnormalities at the time of physical examination; (ii) except for

pattern alopecia, no evidence of additional skin lesions on derma-

tological examination; (iii) for intact female dogs, not being preg-

nant or lactating; and (iv) normal complete blood count and

routine serum biochemical analysis.

Dermoscopic examinationA videodermoscope (Fotofinder� TeachScreen Systems software

GmbH; Bad Birnbach, Germany) was used and six body sites includ-

ing convex pinnae, periaural area, ventral neck, thorax, abdomen and

caudal thighs were selected. Alcohol (Kodan� spray, Schulke & Mayr;

Vienna, Austria) was applied as an interface solution to better

observe surface and subsurface microscopic features.

In order to take a dermoscopic overview image of the selected

cutaneous region, images at 20-fold and 40-fold magnification were

observed initially. Then, as previously reported,11 images at 70-fold

magnification, which allows a high quality enlargement of 9 mm2 of

the skin area to the size of the computer screen, were used for statis-

tical purposes. An area of 3.14 mm2 was calculated on the selected

70-fold images by means of the FotoFinder� software; dogs with pat-

tern alopecia and controls were compared for the following parame-

ters: diameter and total number of hair tufts next to follicular ostia

per examined area; total number of hairs per hair tuft plus the ratio

between the number of secondary hairs/primary hair; and diameter

of both primary and secondary hairs in each hair tuft. Hair follicle

infundibula, perifollicular epidermis and vascular structures such as

very small capillaries were also observed.

Dermoscopy versus histopathologyFor dermoscopic–histopathological correlation, in 20 of the

affected dogs a single skin biopsy taken from the thoracic skin

area previously circled with a marker during dermoscopic exami-

nation was collected under local anaesthesia using a 4–6 mm

skin biopsy punch. The biopsies were fixed in 10% neutral buf-

fered formalin, trimmed, routinely processed and paraffin embed-

ded. Transverse serial sections (4 lm thick) were obtained and

stained with haematoxylin and eosin for histological examination.

Histological images were observed under an Olympus BX51 pho-

tomicroscope equipped with an Olympus C-5060 Wide Zoom and

DP software digital camera (Olympus; Tokyo, Japan) for com-

puter-assisted image acquisition and analysis. The slides con-

tained multiple transverse sections of the skin at different levels

starting from the panniculus and ending with the stratum cor-

neum. For hair follicle number assessment, transverse skin sec-

tions were examined at the level of the mid/lower isthmus. The

total number of follicular units per examined area and number of

total hairs per follicular unit were counted.

Other parameters assessed included: infundibular hyperkeratosis

evaluated in the superficial slides at the level of the infundubulum in

cross-section; vascularization scored in the same slides used to

examine infundibular hyperkeratosis; and pigment clumping evalu-

ated in overall sections and scored according to severity of clumping

in bulbs and hair shafts. Infundibular hyperkeratosis was graded as �(absent), + (mild), ++ (moderate) or +++ (severe); vascularization and

pigment was graded as � (absent), + (weak), ++ (evident) or +++(prominent).

Statistical analysesIn order to assess whether dogs with and without pattern alopecia

were correctly matched for age and body weight, the Mann–Whitney

U-test was used; for sex and hair colour, Fisher’s exact test and an

r 9 c contingency table were used, respectively. For each of the

three dog breeds investigated, dogs with pattern baldness and con-

trols were compared for the measured parameters on the six

selected body regions described above.

The analysis was performed using the Mann–Whitney test fol-

lowed by Bonferroni correction. Furthermore, the same hair

parameters were compared between regions within each dog

breed for those with and without pattern alopecia, using the

Friedman test followed by Dunn’s multiple comparison test. To

assess whether dermoscopic examination yielded similar results

to histology, the Spearman’s rank correlation coefficient was cal-

culated between the total number of hair tufts next to follicular

ostia per examined area based on the former method and the

total number of follicular units per examined area counted with

the latter. The same test was also used to verify whether the

total number of hairs per hair tuft at dermoscopy correlated with

the total number of hairs per follicular unit identified at histology.

Significance was considered with P < 0.05. In addition, Cohen’s

kappa coefficient was used to assess whether there was agree-

ment between the two methods in the analysis of infundibular

hyperkeratosis, vascularization and pigment. j values <0 indicated

no agreement, 0–0.20 slight, 0.21–0.40 fair, 0.41–0.60 moderate,

0.61–0.80 substantial and 0.81–1 as almost perfect agreement.

Software package was used for analysis (GraphPad Prism v.5.0,

GraphPad Software; La Jolla, CA, USA).

Results

Group matching

Population characteristics did not differ statistically in any

of the three breeds between dogs with pattern alopecia

and controls, suggesting appropriate matching.

Table 1. Signalment, age, body weight and sex of selected dogs

used for dermoscopy

Breed and number

of dogs Age (years)

Body

weight (kg) Sex

Controls

Dachshund: 15 4.20 � 0.77 8.09 � 1.84 7F (2 FS); 8M

Italian greyhound: 10 3.50 � 1.13 4.85 � 0.63 6F (2 FS); 4M

Miniature pinscher: 5 2.00 � 1.17 3.89 � 0.70 2 F; 3M

Dogs with pattern alopecia

Dachshund: 15 3.98 � 1.21 7.25 � 1.01 7F (2 FS); 8M

Italian greyhound: 10 3.80 � 1.23 4.88 � 1.31 6F (2 FS); 4M

Miniature pinscher: 5 2.1 � 1.43 3.32 � 1.19 4 F (2FS); 1MN

F, female; FS, spayed female; M, male; MN, neutered male; data are

expressed as mean � SD.

© 2016 ESVD and ACVD, Veterinary Dermatology, 28, 161–e34.162

Zanna et al.

Dermoscopic features

In control dogs, hair shafts were grouped into follicular

units consisting of thick hairs emerging independently

from their follicular ostia and considered as primary hairs,

and surrounded by a variable number of thinner hairs all

protruding through a common external orifice and consid-

ered as secondary hairs (Figure 1a). Other observed fea-

tures included: hair follicle openings that were not empty,

fibrotic or filled with material such as keratotic plugs; no

scaling on perifollicular and interfollicular skin surface; and

thin arborizing red lines corresponding to vessels

between follicular units. All of these findings are illus-

trated in Figure 1b. In dogs with dilute hair colour, pin-

point black spots were also observed on the interfollicular

skin surface.

In dogs affected by pattern alopecia, the most com-

mon dermoscopic finding included primary and sec-

ondary hair shafts that were shorter and thinner than

those of controls (Figure 1c–d). Other findings were:

scattered circle hairs, plugging of the follicular infundibu-

lum with yellow brown material and on periaural and cau-

dal thigh regions, a honeycomb-like pigmented network.

Scattered circle hairs, plugging of the follicular infundibu-

lum with yellow brown material; on periaural and caudal

thigh regions, a honeycomb-like pigmented network. As

in control dogs, dogs with dilute hair colour showed inter-

follicular pinpoint black spots or, in some cases, larger

black spots around hair follicle openings. Thin arborizing

vessels regularly distributed between follicular units were

also detected as in controls. These findings are illustrated

in Figure 2 (a–f).

Dermoscopic parameters

Results are reported in Table S1.

Dachshunds

Comparing dachshunds with pattern alopecia and control

dogs, the following significant differences were docu-

mented: (i) the median diameter of hair tufts next to follic-

ular ostia was smaller in those with pattern alopecia than

control dogs in the convex pinnae (0.05 mm versus

0.08 mm; P < 0.001), ventral neck (0.07 mm versus

0.08 mm; P < 0.01), chest (0.06 mm versus 0.08 mm;

P < 0.05) and abdominal region (0.06 mm versus

0.08 mm; P < 0.01); and (ii) the median diameter of pri-

mary hairs was smaller in those with pattern alopecia in

the ventral neck (0.03 mm versus 0.04 mm; P < 0.05)

and chest (0.03 mm versus 0.04 mm; P < 0.01). In dachs-

hunds with pattern alopecia, the periaural region had a

higher median ratio of secondary hairs/primary hair [7

(range: 4–14)] than the abdominal region [5 (2–8);P < 0.001]. In control dogs, the periaural region had a

smaller median diameter of hair tufts located next to follic-

ular ostia [0.07 mm (0.04–0.08)] than the ventral neck

[0.08 mm (0.07–0.11); P < 0.01], the chest [0.08 mm

(0.06–0.11); P < 0.01] or abdominal region [0.08 mm

(0.06–0.11); P < 0.05], whereas the periaural region had a

smaller median diameter of primary hairs [0.03 mm

a b

c d

Figure 1. Representative hair features in control dogs and dogs affected by pattern alopecia. Control dogs: (a) primary thick hairs surrounded by

thinner secondary hairs (209); (b) normal hair follicle openings from which emerge thick primary hairs surrounded by thinner secondary hairs;

between follicular units, presence of thin arborizing red lines corresponding to vessels and indicated (black arrow) (709). Affected dogs: (c) diffuse

hair thinning (209); (d) both primary and secondary hairs thinner and shorter than in controls. Arborizing red lines are evident between follicular

units (black arrow) (709).


Dermoscopy in canine pattern alopecia

(0.02–0.03)] than either the ventral neck [0.04 mm (0.02–0.05); P < 0.01] or chest [0.04 mm (0.03–0.05); P < 0.01].

Italian greyhounds

Between Italian greyhounds with pattern alopecia and con-

trol dogs, the median diameter of hair tufts next to follicular

ostia was smaller in those with pattern alopecia [0.05 mm

(0.04–0.07)] than control dogs [0.07 mm 0.07–0.08);P < 0.01] in the ventral neck. No other differences were

documented for the hair tuft parameters in any region.

Miniature pinschers

Between miniature pinschers with pattern alopecia and

control dogs, the following significant differences were

documented: (i) the median diameter of hair tufts next to

follicular ostia was smaller in those with pattern alopecia

than control dogs in the convex pinnae (0.05 mm versus

0.08 mm; P < 0.001), ventral neck (0.05 mm versus

0.08 mm; P < 0.05) and caudal thigh region (0.05 mm

versus 0.07 mm; P < 0.05); and (ii) the median diameter

of secondary hairs was smaller in those with pattern

alopecia than control dogs in the convex pinnae

(0.01 mm versus 0.02 mm; P < 0.01), ventral neck

(0.01 mm versus 0.02 mm; P < 0.001) and chest region

(0.01 mm versus 0.02 mm; P < 0.01).

In control dogs the convex pinnae had a higher median

ratio [9 (8–11)] than either the chest [5 (5–6); P < 0.05] or

caudal thigh [5 ( 4–6); P < 0.01].

Histological findings

In transverse histological sections taken from the thoracic

region, hair follicles were characterized by a moderate to

severe decrease in size without distortion or irregularity

of their contour or reduction of the overall number of

adnexal units. Infundibular hyperkeratosis and melanin

clumping were also variably observed, whereas in some

areas, vessels appeared more prominent but not

increased in number.

Dermoscopy versus histopathology

Dermoscopic and histological findings are reported in

Table S2. A very strong positive correlation was observed

a b

c d

e f

Figure 2. Representative follicular and interfollicular dermoscopic features in dogs with pattern alopecia. (a) Hair circles (white arrows) between

miniaturized hairs (209); (b) plugging of the follicular infundibulum with yellow brown material (blue arrows) (409); (c) hair circles (black arrow), thin

arborizing vessels (red arrow) and plugging of the follicular infundibulum (blue arrow) (709); (d) honeycomb-like pattern (black arrows) on the caudal

thigh (709); (e) pinpoint black dots in a dog with diluted hair colour (black arrow) (709); (f) large black dots around hair follicles in a dog with diluted

hair colour (709).


Zanna et al.

for the total number of hair tufts next to follicular ostia

based on dermoscopy and the total number of follicular

units per examined area counted with histological examina-

tion (rho = 0.898; 95% CI = 0.750–0.961; P < 0.001).

Also, the total count of hairs per hair tuft at dermoscopy

correlated with the total number of hairs per follicular unit

identified with histological examination (rho =0.868; 95% CI = 0.683–0.948; P < 0.001) (Figure 3). A fair

agreement was observed between dermoscopic and

histopathological findings for the analysis of follicular hyper-

keratosis (j = 0.333; 95% CI = 0.013–0.679) with 12 of 20

(60%) agreements, vascularization (j = 0.200; 95%

CI = 0.120–0.520) with nine of 20 (45%) agreements and

pigment (j = 0.294; 95% CI=0.032–0.556) with 11 of 20

(55%) agreements.

Discussion

In this study dermoscopic findings in dogs affected by

pattern alopecia have been characterized for the first

time, highlighting the value of dermoscopy as an adjunc-

tive technique for cutaneous clinical examination.

Canine pattern alopecia is a relatively common but

poorly studied skin disorder somehow similar to, but

also clearly different from, human androgenetic alope-

cia.18 Fine hairs referred to as miniaturized hairs repre-

sent the hallmark clinical presentation of the disorder in

people. However, to the best of the authors’ knowl-

edge, in vivo measurement of hair shaft thickness

based on dermoscopy has not been performed before

in dogs. In this study, the first hair parameter mea-

sured dermoscopically was the median hair tuft thick-

ness diameter next to follicular ostia, which was

shown to be smaller in all affected dogs compared

with controls. This result is not surprising if we con-

sider that the relative thinning of hairs is the most strik-

ing feature of the disease. Of note, however,

differences between breeds and within the same breed

were detected, dependent on other hair parameters

accounted for. For example, in affected dachshunds

the median ratio between the number of secondary

hairs:primary hairs was shown to be higher in diseased

animals than in controls in all the skin regions evalu-

ated. The periaural region demonstrated the largest

number of secondary hairs. Moreover, within the group

of dachshund dog controls, the periaural region was

demonstrated as having the smallest median diameter

of primary hairs, indicating that thinning of hairs in this

region may be considered as a normal feature in this

breed. In Italian greyhounds, the ventral neck region

was described as affected mainly by thinning hairs, and

this finding indicates the relevance of this region in dis-

tinguishing affected from healthy dogs. In miniature

pinschers, secondary hairs were smaller in affected

dogs than in control dogs, mostly in the convex pinnae,

ventral neck and chest areas, whereas in control dogs

the median number of secondary hairs:primary hairs

ratio was higher in the convex pinnae. All of these

results taken together reveal that hair shaft thinning in

canine pattern alopecia is a process that does not

simultaneously affect all hairs of all regions, and that

great variability exists between and within affected dog

breeds. This variability may be the result of artificial

selection pressure for extremely fine hair coats sought

by breeders who often attempt to manipulate the

appearance of a dog, thereby predisposing it to this

presumptively genetic alopecia.19

In order to provide both qualitative and quantitative

diagnostic follicular information, transverse sections of

skin biopsy specimens were used in this study, as in

human studies.20,21 Some key information such as follic-

ular counts was easily assessed and histological findings

were shown to positively correlate with dermoscopic

calculations of hair parameters. However, accurate

determination of growth stages of the hair cycle was not

possible on transverse sections due to the absence of

the entire length of the hair follicle including site, shape

and depth of the hair inferior portion and, specifically, of

the bulb. Therefore, longitudinal sections may continue

to provide the best morphological and spatial information

to assess specific growth stages of the hair cycle in

dogs.

In order to detect other dermoscopic features that

could differentiate diseased dogs from controls, hair

follicle openings, perifollicular and interfollicular skin sur-

face, and vascular structures were examined dermo-

scopically and evaluated in conjunction with histological

findings. Follicular ostia filled with light yellowish or

brownish material were observed mostly in the ventral

regions of dogs affected by pattern alopecia; histologi-

cally, this was related to a variable amount of keratin

filling the follicular infudibulum. In humans, this dermo-

scopic finding, termed ‘yellow dot’, represents sebum

mixed with variable amounts of keratin secreted by

normal, active sebaceous glands through the miniatur-

ized hair follicle.7,9,11 Therefore, the result of this

process is the accumulation of yellow material in the fol-

licular infundibula. In spite of a fair agreement between

dermoscopy and histopathology that might have been

influenced by preparation of the biopsy site, our hypoth-

esis is that a similar mechanism may occur in canine pat-

tern alopecia.

Moreover, in some affected dogs, hairs with typical

circular or spiraliform arrangement were observed

Figure 3. Correlation of the number of hair tufts located next to fol-

licular ostia based on dermoscopy (x-axis) with number of follicular

units counted with histology (y-axis). The regression line is shown.



dermoscopically, but no histopathological change was

identified in relation to this dermoscopic feature. In

humans, circle hairs are seen on the abdomen, buttocks,

trunk and upper legs, as coiled hairs without any signs

of follicular abnormality. Their pathogenesis is still

unclear; some authors believe they correspond to rem-

nants of the mammal undercoat, and others postulate

that they are hairs with a smaller diameter making it dif-

ficult for the hairs to perforate the stratum corneum,

resulting in coiling underneath the skin surface.22,23

Based on this, our dermoscopic finding could provide an

explanation, but further studies are necessary to better

understand the pathogenesis of these hairs with this

typical arrangement.

Agreement between dermoscopy and histopathology

was demonstrated for pigment, mostly in dogs with

dilute hair colour, probably as a result of abnormal

melanin deposition in and around hair follicles. Pin-

point and large black spots corresponding to melanin

clumping were dermoscopically observed on the inter-

follicular skin surface and this finding may open new

insights into the application of dermoscopy for other

skin disorders.

Finally, a honeycomb-like hyperpigmentation pattern,

characterized by hyperchromic rings on the skin sur-

face and resulting from solar exposure in thinning or

completely balding areas, as demonstrated in humans,

often coexisted as an additional feature in the periaural

and caudal thigh regions.10 However, these regions

were not selected for histological correlation and this

finding requires further studies in order to be better

elucidated.

Cutaneous microvessels that arborize into thin red

branches in a nonhomogeneous fashion were considered

as nonspecific dermoscopic findings because they are

also common in normal skin. Given that dermoscopy

enables horizontal inspection of the skin, vessels that run

parallel to the skin surface are visualized as lines,

whereas those that run perpendicularly are generally

viewed as dots, or even loops.24,25 However, they are

best evaluated when the pressure exerted by the dermo-

scope against the skin is low. High outside pressure may

indeed reduce blood flow in cutaneous capillaries.10 In

this study, the lack of dermoscopic visualization of cuta-

neous blood vessels in some selected areas and the fair

agreement demonstrated with histopathology may have

resulted from excessive pressure applied to the skin with

the dermoscopy instrument. Translucent ultrasound gel

that allows gentler application of the lens against the skin

in order to better visualize blood vessels could be used in

future studies.

In summary, the results of this study suggest that

although pattern alopecia is a visually striking disease,

dermoscopy provides additional information beyond

that obtained by evaluating the lesions through a derma-

tological examination. Besides hair thinning, new der-

moscopic features have been identified offering the

clinician a novel way in which to uncover clinical aspects

of hair disorders. In the future, dermoscopy may be of

benefit in further studies to differentiate various hair

disease states.

Acknowledgements

The authors are grateful to the clients and amateur pet

breeders who permitted us to carry out this study. We

would also like to thank Adelaide Pap�o for her invaluable

help in selecting dogs.

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Supporting Information

Additional Supporting Information may be found in the

online version of this article.

Table S1. Results of dermoscopic hair parameters in both

affected and control dogs.

Table S2. Dermoscopic histological correlation of quanti-

tative and qualitative parameters.

R�esum�e

Contexte – Les �etudes dermoscopiques portant sur l’alop�ecie progressive non prurigineuse non inflamma-

toire attribuable �a une alop�ecie en patron sont actuellement indisponible.

Hypoth�eses/Objectifs – �Evaluer les crit�eres dermoscopiques de la peau saine des chiens �a poils courts et

de comparer ces donn�ees �a celles observ�ees chez les chiens atteints d’alop�ecie en patron diagnostiqu�ee

par examen clinique ou dermatopathologique.

Sujets – Trente chiens males et femelles, sains, crois�es, jeunes adultes, �a pelage court (controles) et 30

chiens males et femelles, jeunes adultes, �a pelage court atteints d’alop�ecie en patron.

M�ethodes – La dermoscopie a �et�e r�ealis�ee par un vid�eodermoscope Fotofinder II �equip�e d’un logiciel per-

mettant la mesure des structures visualis�ees en image grossie (209–4099-7099). Des biopsies cutan�ees

ont �et�e r�ealis�ees au niveau du thorax et �evalu�ees par dermoscopie pour corr�elation dermatopathologique

chez les chiens atteints.

R�esultats – Les donn�ees dermoscopiques de l’alop�ecie en patron �etaient un amincissement des tiges pilai-

res, des manchons pilaires et des poils incurv�es; dans les zones expos�ees au soleil il y avait un patron de

pigmentation en nid d’abeille. Des lignes rouges arborescentes, refl�etant la vascularisation, ont �et�e clas-

sifi�ees comme donn�ee non sp�ecifique, �etant assez fr�equent �egalement chez les chiens sains. Les crit�eres

dermoscopiques corr�elaient avec l’histologie des anomalies folliculaires s�electionn�ees.

Conclusions et importance clinique – Bien que l’alop�ecie en patron soit une maladie visuellement sin-

guli�ere, cette �etude rapporte l’int�eret de la dermoscopie pour l’examen clinique et aussi ouvre de promet-

teuses perspectives pour l’identification et le diagnostic des patrons dermoscopiques qui pourraient etre

utiles pour d’autres atteintes cutan�ees.

Resumen

Introducci�on – estudios dermosc�opicos evaluando la alopecia no inflamatoria, no pruriginosa progresiva

conocida como alopecia en patr�on definido no est�an disponibles actualmente.

Hip�otesis/objetivos – Evaluar las caracter�ısticas dermosc�opicas observadas en la piel sana de perros de

pelo corto y comparar estos resultados con los observados en los perros afectados por alopecia de patr�on

definido diagnosticada tras examen cl�ınico y dermatopatol�ogico.

Animales – Treinta perros machos y hembras, sanos, emparejados por raza, adultos j�ovenes de pelo corto

(controles) y 30 perros machos y hembras, j�ovenes adultos de pelo corto afectados por la alopecia.

M�etodos – la dermoscop�ıa se realiz�o con un videodermoscopio Fotofinder II equipado con un software

que permite la medici�on de estructuras visualizadas en im�agenes ampliadas (20 9 -409x -709 9). Muestras

de biopsia de la piel se obtuvieron de t�orax y se mediante dermoscop�ıa para poder realizar una correlaci�on

dermoscop�ıa-histolog�ıa en los perros afectados.

Resultados – los hallazgos dermatosc�opicos en la alopecia de patr�on definido en perros fueron dismi-

nuci�on del grosor del cabello, pelos circulares y tapones de queratina foliculares; en las �areas afectadas

expuestas al sol hab�ıa un patr�on en forma de panal de la pigmentaci�on. L�ıneas ramificadas rojas que refleja-

ban la vascularizaci�on se clasificaron como un hallazgo inespec�ıfico, ya que tambi�en eran comunes en per-

ros sanos. Las caracter�ısticas dermatosc�opicas se correlacionaron con la histolog�ıa en las anormalidades

del pelo seleccionadas.

Conclusiones e importancia cl�ınica – Aunque la alopecia de patr�on definido canina es una enfermedad

visualmente impactante, este estudio apoya el valor de la dermoscopia para el examen cl�ınico y tambi�en

abre perspectivas prometedoras para la identificaci�on de patrones dermosc�opicos de diagn�ostico que pue-

den ser �utiles para otros trastornos de la piel.

Zusammenfassung

Hintergrund – Zurzeit gibt es keine dermoskopischen Untersuchungen, die nichtentz€undliche, nichtju-

ckende progressive Alopezie analysierten, welche einer Pattern Alopezie zugeschrieben werden konnte.

Hypothese/Ziele – Eine Evaluierung der dermoskopischen Merkmale, die in gesunder Haut von Hunden

mit einem kurzen Haarkleid beobachtet werden k€onnen und ein Vergleich dieser Befunde mit jenen, die bei

Hunden, die mittels klinischer und dermatopathologischer Untersuchung mit einer Pattern Alopezie diagno-

stiziert worden waren.



Tiere – Dreißig m€annliche und weibliche, gesunde, den Rassen angepasste, erwachsene, kurzhaarige

Junghunde (Kontrollen) und 30 m€annliche und weibliche, kurzhaarige Junghunde, die eine Pattern Alopezie

aufwiesen.

Methoden – Die Dermoskopie wurde mit einem Fotofinder II Videodermoskop, welches mit einer Soft-

ware ausgestattet war, die eine Messung der Strukturen, die in den Vergr€oßerungsaufnahmen (20x-409x-

709x) sichtbar gemacht werden konnten, erlaubte. Hautbiopsien wurden vom Thorax entnommen und der-

moskopisch evaluiert, um eine dermoskopisch-histologische Korrelation bei den betroffenen Hunden zu

erstellen.

Ergebnisse – Die dermoskopischen Befunde bei der Pattern Alopezie des Hundes bestanden aus Haar-

schaftverd€unnung, kreisrunden Haaren und follikul€aren Keratinpfropfen; an den der Sonne ausgesetzten

Stellen bestand eine Honigwaben-artige Pigmentierung. Die €Aste-bildenden roten Linien, die die Vaskulari-

sierung reflektierten, wurden als nichtspezifische Befunde klassifiziert, weil sie auch bei gesunden Hunden

h€aufig auftraten. Die dermoskopischen Merkmale korrelierten mit der Histologie selektiver Haarfollikelab-

normalit€aten.

Schlussfolgerungen und klinische Bedeutung – Obwohl die Pattern Alopezie des Hundes eine visuell

markante Erkrankung darstellt, st€utzt diese Studie den Wert der Dermoskopie als Teil der klinischen Unter-

suchung und er€offnet eine vielversprechende Perspektive zur Identifizierung der diagnostischen dermosko-

pischen Muster, die auch f€ur andere Hauterkrankungen hilfreich sein k€onnten.

要約

背景 – パターン脱毛症に起因する非炎症性、非掻痒性進行性脱毛症を評価しているダーモスコピーの研究は、今の所存在しない。仮説/目的 – 短毛種のイヌの健康な皮膚において認められるダーモスコピーの特徴を評価すること、およびそれらの特徴を臨床、病理組織学的な検査によりパターン脱毛症と診断されたイヌで観察された所見と比較することである。供与動物 – 30頭の雄および雌の健康で犬種が合致し、若い成犬、短毛種のイヌ(対照群)および30頭の雄および雌

の若い成犬でパターン脱毛症に罹患した短毛種のイヌ。方法 – 拡大画像(209–4099-7099)を視覚化し、構造の計測が可能なソフトウエアが装備されたFotofinder IIvideodermoscopeを用いてダーモスコピーを行った。皮膚生検材料を胸部から採取し、罹患したイヌにおいてダーモスコピー�組織学関連性を、ダーモスコピーを用いて評価した。結果 – イヌのパターン脱毛症におけるダーモスコピー所見は毛軸が細くなること、輪状毛およびに毛包ケラチン塞栓が認められ、日光に暴露された罹患部位は蜂の巣状のパターンの色素沈着が認められた。血管新生を反映した樹の枝状の赤い線は健康なイヌでも一般的であったため、非特異所見と分類された。ダーモスコピーの特徴は毛包異常

が認められた部位の組織学的特徴と相関していた。結論および臨床的な重要性 – イヌのパターン脱毛症は視覚的に分かりやすい疾患であるが、この研究は臨床検査のためのダーモスコピーの価値を支持し、また、他の皮膚疾患のために有用な可能性のある、診断的なダーモスコピーのパターンの特定のために、期待できる考え方となる。

摘要

背景 – 目前还不能利用皮肤镜来确定模式脱毛引起的非炎性、非瘙痒性脱毛。假设/目的 – 评估正常短毛犬皮肤的皮肤镜特征,并与模式脱毛的患犬进行比较,这些病例已经临床和皮肤病

理学确诊。动物 – 三十只雄和雌性、健康的、品种相当的、青年短毛犬(对照组),以及三十只雄和雌性、青年、短毛、模式脱毛患犬。方法 – 使用Fotofinder II皮肤镜检查皮肤,其安装了可对放大图像(209–4099-7099)进行测量的软件。取

胸部皮肤活检样本,分别使用皮肤镜和组织病理评估。结果 – 皮肤镜发现模式脱毛患犬的皮肤毛发稀疏、毛发周围及毛囊角质栓塞;日照部位有蜂窝样色素沉积模

式。树枝状红线是血管化的反映,被归为非特异性变化,因为这也常出现在其他多种皮肤病患犬身上。皮肤镜

和组织学结果交集为毛囊异常。总结与临床意义 – 尽管犬模式脱毛是直观的特征鲜明的疾病,本研究支持皮肤镜的临床检查价值,也开启了

皮肤镜诊断鉴定模式,有望未来用于其他皮肤疾病的诊断。

Resumo

Contexto – Estudos dermatosc�opicos avaliando alopecia progressiva n~ao pruriginosa e n~ao inflamat�oria,

associada �a alopecia padr~ao, est~ao indispon�ıveis no momento.

Hip�otese/Objetivos – Avaliar as caracter�ısticas dermatosc�opicas observadas na pele h�ıgida de c~aes de

pelagem curta, e comparar estes resultados com os encontrados em c~aes afetados por alopecia padr~ao,

diagnosticada por exames cl�ınico e histopatol�ogico.

Animais – Trinta c~aes machos e femeas de pelagem curta, jovens adultos, h�ıgidos, de rac�as pareadas

(grupo controle) e trinta c~aes machos e femeas de pelagem curta, jovens adultos e afetados pela alopecia

padr~ao.

M�etodos – A dermatoscopia foi realizada utilizando o Fotofinder II videodermoscope equipado com um

programa que permite a mensurac�~ao das estruturas visualizadas nas imagens magnificadas (20x – 409x –

Zanna et al.

© 2016 ESVD and ACVD, Veterinary Dermatology, 28, 161–e34.e33

709x). Bi�opsias de pele foram obtidas da regi~ao do t�orax e avaliadas dermatoscopicamente para correlac�~aode dermatosc�opica e histopatol�ogica em c~aes afetados.

Resultados – Achados dermatosc�opicos na alopecia padr~ao canina foram adelgac�amento das hastes pilo-

sas, pelos circulares e tamp~oes de queratina. Nas �areas expostas �a radiac�~ao solar, nos animais afetados,

havia um padr~ao de pigmentac�~ao similar a colmeias de abelhas. Linhas vermelhas ramificadas indicando

vascularizac�~ao foram classificadas como um achado n~ao espec�ıfico porque tamb�em foram comuns nos

c~aes h�ıgidos. Caracter�ısticas dermatosc�opicas correlacionaram com determinadas alterac�~oes do fol�ıculo

piloso.

Conclus~oes e importancia cl�ınica – Apesar da alopecia padr~ao canina ser uma doenc�a visualmente singu-

lar, este estudo reitera o valor da dermatoscopia para o exame cl�ınico al�em de abrir promissoras perspecti-

vas para a identificac�~ao de padr~oes dermatosc�opicos que podem ser �uteis para outras dermatopatias.


© 2016 ESVD and ACVD, Veterinary Dermatology, 28, 161–e34. e34

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