Trichoscopy as an aid in the diagnosis of trichotillomania.

Sir,

Trichoscopy is gaining popularity as a valuable tool in the diagnosis of hair loss and has almost become inevitable in trichology practice. Structures which may be visualized by trichoscopy include hair shafts of different types, hair follicles and abnormalities of scalp skin color or structure.[12] Trichoscopy is done using a hand-held dermoscope at a working magnification of 20x. Trichoscopy can also be used to perform dermoscopic trichogram, which is a simple, reliable and rapid diagnostic method of examining the plucked hair roots for disorders of hair growth.[3]

Trichotillomania is a chronic impulse control disorder characterized by repetitive hair pulling resulting in alopecia.[4] This conscious or subconscious habit or tic is most commonly performed by young children, adolescents and women. Many children have a benign self-limited form of hair pulling. The favorite site is the easily reached frontoparietal region of the scalp followed by eyelashes, eyebrows, pubic hair, body hair and facial hair.[5] It has to be differentiated from alopecia areata and noninflammatory tinea capitis.

An 8-year-old boy presented with a patchy loss of hair over the temporal region of the right side of scalp of 2-weeks duration. The affected area had an irregular angulated border and the density of hair was greatly reduced over the patch [Figure 1]. Several short broken hairs of varying lengths were randomly distributed in the involved site. The patient denied any history of hair pulling. On examination the hair pull test was negative.

Figure 1

Patchy hair loss in a young boy

A KOH smear was done to rule out noninflammatory tinea capitis.

Trichoscopic examination at 20× magnification showed short broken hairs of varying lengths. [Figure 2]. Scalp surface was normal. Dermoscopic trichogram showed the presence of atrophic sharply angulated rigid root like a spade characteristic of catagen hairs and complete absence of telogen hairs typical of trichotillomania [Figure 3]. Based on the clinical findings and characteristic trichoscopic features a diagnosis of trichotillomania was made.

Figure 2

Trichoscopy showing broken hairs of varying lengths

Figure 3

Dermoscopic trichogram showing catagen hair

Trichotillomania has to be differentiated from other causes of patchy nonscarring hair loss like alopecia areata and noninflammatory tinea capitis. A KOH and Woods lamp examination can rule out noninflammatory tinea capitis. Although patches of alopecia areata are completely devoid of hair, sometimes in atypical cases diagnosis cannot be completely established solely on the basis of clinical appearance. Hair pull test can some times help to differentiate between the two but it is present only in the active phase of alopecia areata and it is usually at the margins. Light microscopy helps to differentiate between the two but it is invasive and difficult to perform in children. In view of the simplicity, noninvasiveness, and less need for a technical expertise to handle, trichoscopy definitely has an edge over the conventional diagnostic tools in differentiating trichotillomania from alopecia areata.

Most characteristic trichoscopic features of alopecia areata include regularly distributed hyperkeratotic plugs in the hair follicles (yellow dots), cadaverised hairs (black dots), microexclamation mark hairs (visible when 1 mm or less in length) dystrophic and regrowing hairs.[6] Dermascopic trichogram shows the presence of dysplastic and dystrophic anagen hairs. In trichotillomania trichoscopy shows the presence of broken hairs of varying lengths. Dermoscopic trichogram shows catagen hairs and anagen hairs with ruptured root sheaths with the absence of telogen hairs. This case is reported to highlight the characteristic trichoscopic features of trichotillomania and how trichoscopy and dermoscopic trichogram can help the clinician far better than the other methods in the diagnosis of atypical cases of hair loss.