|Year : 2014 | Volume
| Issue : 4 | Page : 762-765
Dermoscopy in hair disorders
Iman A Seleit1, Olaa A El-Bakry1, Rawnaa M El-Sherif2
1 Department of Dermatology; Department of Andrology, Faculty of Medicine, Menoufia University, Berket El Sabea, Menoufia, Egypt
2 Berket El Sabea Hospital, Egyptian Ministry of Health, Egypt
|Date of Submission||23-Dec-2013|
|Date of Acceptance||10-Apr-2014|
|Date of Web Publication||22-Jan-2015|
Olaa A El-Bakry
Dermatology, Andrology Department, Faculty of Medicine, Menoufia University, Menoufia
Source of Support: None, Conflict of Interest: None
Hair loss can have significant effects on patients' quality of life, and a prompt diagnosis of the different types of alopecias and early intervention are needed. This review highlights the main dermoscopic findings in the different types of alopecia, such as androgenetic alopecia, alopecia areata, trichotillomania, lichen planopilaris, and discoid lupus erythematosus of the scalp. We believe that this important tool has been demonstrated to help dermatologists in finding the right site for the biopsy or, furthermore, avoiding unnecessary biopsies. Data sources were medical text books, medical journals, and medical websites that have updated research with the key word Dermoscopy in the title of the paper. Systematic reviews that addressed dermoscopy, its impact on dermatological lesions, and the role of physicians in prevention and management were selected. A special search was conducted at midline with the key word Dermoscopy in the title of the papers; extraction was made, including assessment of the quality and the validity of papers that met the prior criteria that describe Dermoscopy and its use in the diagnosis of hair disorders. Each study was reviewed independently, and the data obtained were rebuilt in new language according to the need of the researcher and arranged into topics through the article. Hair and scalp dermoscopy (trichoscopy) is a fast and noninvasive technique that allows the identification of hair and scalp diseases on the basis of analysis of trichoscopy structures and patterns without the need for removing hair for diagnostic purposes or unnecessary biopsies. Dermoscopy may be useful in the differential diagnosis of various hair and scalp disorders such as alopecia areata, androgenetic alopecia, and tenia capitis and also in the differential diagnosis between discoid lupus erythematosus and lichen planopilaris.
Keywords: Alopecia, dermoscopy, discoid lupus erythematosus, lichen planopilaris, trichotillomania
|How to cite this article:|
Seleit IA, El-Bakry OA, El-Sherif RM. Dermoscopy in hair disorders. Menoufia Med J 2014;27:762-5
| Introduction|| |
Hair loss can have significant effects on patients' quality of life, and a prompt diagnosis of the different types of alopecias and early intervention are necessary when dealing with these patients. The standard methods to diagnose hair and scalp disorders, such as simple clinical inspection, the pull test, and biopsy, vary in their reproducibility and invasiveness, and there is a need for noninvasive methods that help the clinician in everyday practice. The use of dermoscopy improves the diagnostic accuracy and may contribute in understanding the pathogenesis of hair disorders .
For scalp examination, dermatologists can use a manual dermoscope (×10 magnification) or a videodermoscope equipped with various lenses (from ×20 to ×1000 magnification). Dermoscopy findings include vascular patterns, follicular and perifollicular signs, and hair shaft characteristics .
Examination of the normal scalp can show simple fine red loops that represent capillary loops in the dermal papilla1. In dark-skinned individuals, a perifollicular pigmented network (honeycomb pattern) is well appreciated. The network consists of hyperchromic lines that represent melanocytes in the rete ridge system in contrast to hypochromic areas formed by a few melanocytes localized in the suprapapillary epidermis . Follicular units in the normal scalp contain two to four terminal hairs and one or two vellus hair inside.
In scalp psoriasis, within the typical scaly plaques, twisted red loops are observed at a higher magnification (×70) [Figure 1]. Twisted loops are also seen to a limited extent in unaffected psoriatic scalp and in newly treated psoriatic scalp. There is a direct correlation between the morphology of the loop and the state of the overlying epidermis, and twisted loops occur under conditions of epidermal hypertrophy with a psoriasiform pattern. In seborrheic dermatitis, arborizing red lines, which have a wider caliber than the loops, can be observed. This may be helpful in the differentiation of these two scaly conditions. However, capillary loop density seems to be similar in patients with psoriasis, seborrheic dermatitis, and healthy scalp skin, and sometimes twisted loops are observed in sebopsoriasis-like forms of seborrheic dermatitis .
|Figure 1: A typical scaly psoriatic plaque with numerous twisted red loops observed in the scalp.|
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In alopecia areata (AA), the characteristic findings of AA that are detected using dermoscopy are dystrophic hair and yellow dots. Moreover, clustered vellus hairs were found in some areas of alopecia . Vellus hairs may be white . Coudability hairs may be seen the perilesional area  [Figure 2].
|Figure 2: Alopecia areata: numerous pink to yellow dots arranged in groups of two to three dots along the alopecic patch.|
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The yellow dot pattern is seen at ×20 magnification or greater .
Yellow dots are described as yellow to yellow red, round or polycyclic dots of different sizes . These dots represent follicular openings filled with keratinous debris (degenerating follicular keratinocytes) mixed with sebum . This is supported by findings on light microscopy and the observation that degreasing of an affected area with acetone leads to a decrease in the dot size .
Visualization of classic findings of active disease such as dystrophic hairs, exclamation mark hairs, and cadaverized hairs as well as regrowth of vellus hairs has improved beyond simple clinical inspection . Recently, Inui et al.  showed that for diagnosis, yellow dots and short vellus hairs were the most sensitive markers, and black dots, tapering hairs, and broken hairs were the most specific markers of the disease. Black dots, tapering hairs, and broken hairs correlated positively with disease activity. Multiple depressed follicular ostia may be observed under dry dermoscopy. It has been suggested that these represent abnormal hair follicles containing incompletely differentiated hair shafts .
AA incognita is a variety of AA that mimics androgenetic alopecia (AGA) and telogen effluvium, with the development of diffuse and severe hair thinning within a few months. Under dermoscopy, yellow dots are evident within the follicular ostium of both empty and hair-bearing follicles in about 70% of the follicles and a large number of regrowing, tapered, terminal hairs are evident in the entire scalp [Figure 3] .
|Figure 3: Alopecia areata incognita: yellow dots can be observed within the follicular ostium of both empty and hair-bearing follicles.|
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Dermoscopy findings are also important to differentiate trichotillomania from AA. Initially, hairs that are broken at different distances from the scalp and longitudinal splitting of hair shafts can also be seen .
AGA is characterized by hair diameter diversity due to miniaturization of the hair follicles. A variability in the hair shaft diameter of more than 20% of the hair shafts is diagnostic of this condition [Figure 4] . In early AGA, it is common to see peripilar brown depressions described as peripilar signs . In patients with advanced AGA, yellow dots can be observed and the sun-exposed scalp often shows a honeycomb pigment pattern.
|Figure 4: A variability in the hair shaft diameter of more than 20% of the hair shafts is diagnostic of androgenetic alopecia.|
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Dermoscopy allows measurement and monitoring of hair shaft thickness in AGA, where it may also help in calculating the terminal-to-vellus hair ratio . On dermoscopy, under higher magnifications, it is possible to identify and count vellus hairs (with <0.03 mm width) . It is worthwhile to note that follicular ostia in AGA show a predominance of single hairs, instead of 2-4 hair shafts observed in normal individuals .
Primary cicatricial alopecias are a large group of disorders characterized by permanent destruction of the hair follicle. Presumably, all of them result from irreversible injury of the stem-cell-rich bulge area, which is required for the cyclic regeneration of the lower follicle . One of the hallmark features is the absence of follicular ostia and the presence of fibrous tracts that mark extinct follicles on pathology, as observed by Kossard and Zagarella .
In lichen planopilaris (LPP), dermoscopy reveals an absence of follicular openings and the presence of characteristic perifollicular scales (peripilar casts) at the periphery of the patch. Perifollicular erythema, characterized by the presence of arborizing vessels around the follicular ostia, is also observed [Figure 5].
A pigmented network is well appreciated in dark-skinned individuals inside the plaques of hair loss . As the interfollicular epidermis is commonly unaffected by the inflammatory process in LPP, we believe that this sign may help in differentiating this type of alopecia from other scarring alopecias as discoid lupus erythematosus (DLE) of the scalp .
|Figure 5: Lichen planopilaris: perifollicular erythema and hyperkeratosis as well as a discrete pigmented network are well appreciated in this case. The absence of follicular ostia and terminal hair follicles are also evident inside the alopecic plaque.|
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White pale dots distributed between the pigmented network were reported by Kossard and Zagarella .
In dark-skinned patients a focal decrease in the pigmentation of the rete ridges above the fibrous tracts probably accounts for the pale color seen clinically, which is a hallmark of extinct follicles .
Blue-grey dots may be found in some patients, especially in individuals with dark skin. A peculiar 'target pattern' of round perifollicular blue-grey dots may be observed in some dark patients with LPP. Histopathologically, these dots are caused by loose melanin, fine melanin particles, or melanin 'dust' in melanophages or free in the deep papillary or the reticular dermis. The 'target pattern' is associated with the presence of melanophages predominantly around hair follicles, sparing the interfollicular epidermis . Usually, LPP spares some terminal hair follicles inside the alopecic patches.
In frontal fibrosing alopecia, a clinical variant of LPP, the most prominent dermoscopic findings are loss of follicular openings, peripilar scales, and peripilar erythema .
In DLE, the affected scalp shows erythema, scaling, follicular plugging, atrophy, and telangiectasias. Despite the fact that it is considered as a part of the group of cicatricial alopecias, DLE may show hair regrowth if treated promptly. Hence, early diagnosis is important for patients' prognosis.
Under dermoscopy, scalp atrophy is represented by a diffuse white color of the scalp. This pattern is well appreciated in dark-skinned patients, who lose the normally seen pigmented network within the lesion .
The honeycomb pigmented network might be seen at the periphery of the plaque of DLE .
Arborizing and tortuous vessels are the most common vascular patterns seen inside DLE plaques. A peculiar finding of red to pink-red, round and polycyclic dots that are uniform in size and regularly distributed around follicular openings may be also observed .
Hyperkeratotic follicular pluggings are observed in the follicles around the patches. Blue-grey dots may be observed, with a diffuse and speckled pattern of distribution along the patch . These dots represent pigmentary incontinence in the papillary dermis of follicular and interfollicular epidermis. We believe that the different patterns of blue-grey dots described may be an interesting feature to help dermoscopic differentiation between DLE and LPP .
- Introduction of dermoscopy as a routine diagnostic tool in dermatological examination will be of an excellent aid for accurate diagnosis.
- Studying the role of dermoscopy in the diagnosis of diseases such as spongiotic dermatitis, urticaria, urticarial vasculitis, squamous cell carcinoma, and comedones in acne commonly seen in Egypt.
- Correlation between dermoscopic appearance and histopathology examination are required to improve diagnosis.
| Conclusion|| |
Dermoscopy is a useful diagnostic tool that is commonly used in western countries and in Egypt. It improves our diagnostic capabilities and thus helps us to reduce unnecessary biopsies as it is an easy, rapid, noninvasive, and reliable diagnostic technique.
| Acknowledgements|| |
Conflicts of interest
There are no conflicts of interest.
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[Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5]