Lichen Planus and Alopecia Areata Co-Localization.

Sir,

Lichen planus (LP) has been associated with a number of autoimmune diseases including alopecia areata (AA). Although the co-occurrence of LP and AA has commonly been reported, there is a paucity of literature on the co-localization of the two conditions.[1]

A 30-year-old man presented with a 2-month history of a mildly itchy violaceous plaque over the occiput. After about 4 weeks, the patient had noticed an area of hair loss surrounding the initial lesion but without any symptoms or surface changes. The patient was otherwise well with no systemic complaints. Past medical and family history was unremarkable.

Cutaneous examination revealed a patch of non-scarring alopecia about 5 × 4 cm in size over the occipital area of the scalp. A single well defined round violaceous plaque of about 2 × 1.5 cm was present at the center of the alopecic patch [Figure 1]. There was no skin lesion or loss of hair over other body sites. Mucosal and nail examinations were normal. Two punch biopsies were taken. Histopathology of the violaceous plaque revealed hyperkeratosis, wedge-shaped hypergranulosis, irregular acanthosis, basal cell liquefaction, and a band-like lymphocytic infiltrate and pigment? incontinence suggestive of a diagnosis of LP and that of alopecic patch revealed a perifollicular “swarm of bees”-type lymphocytic infiltrate consistent with the diagnosis of AA [Figures 2 and 3]. Based on clinical and histopathology findings, the diagnosis of co-localization of LP and AA was made.

Figure 1

Non-scarring alopecic patch with a violaceous plaque at the center

Figure 2

Basal cell degeneration with band-like lymphocytic infiltrate at the dermoepidermal junction and pigment incontinence (H and E, 100Ö)

Figure 3

Perifollicular lymphocytic infiltrate with the typical “swarm of bees” appearance (H and E, 400×)

Both LP and AA have frequently been described in association with other autoimmune disorders such as thyroid disease, diabetes mellitus, vitiligo, pernicious anemia etc. About 25% of patients with one autoimmune disease have a tendency to develop additional autoimmune disease. Multiple autoimmune syndrome (MAS) is the coexistence of three or more autoimmune diseases. In MAS, patients often have at least one dermatological condition.[2] There are reports on anatomic co-habitation of autoimmune skin diseases like vitiligo and LP, vitiligo, and AA.[13] There have been many reports on the co-occurrence of LP and AA, however, their anatomical co-localization remains scarcely reported. The co-localization of LP and AA can possibly be explained based on a common T-cell mediated pathogenesis in the two conditions.[14]

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Conflicts of interest

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