Vitiligo as an adverse reaction to topical diphencyprone.

Dear Editor, Diphencyprone (DCP) is a contact sensitiser used to treat dermatological conditions resulting from an altered immunological state, such as extensive alopecia areata. Adverse effects include local eczema with blistering, regional lymphadenopathy and contact urticaria. Rare adverse effects include an erythema multiforme-like reaction, hyperpigmentation, hypopigmentation and vitiligo. We report 4 patients with alopecia areata who developed the rare side-effect of vitiligo following DCP immunotherapy (Table 1). The patients’ ages ranged from 12 to 67 years old, with the mean duration of DCP therapy before the onset of vitiligo being 10.5 months. Most of the patients had previously failed intralesional triamcinolone therapy, except for patient 3 who had been started on SABDE (squaric acid dibutyl ester) and subsequently DCP because of her young age and extent of alopecia. The typical concentration of DCP used was variable, with vitiligo developing with concentrations as low as 0.0001% in patient 2. Vitiligo was preceded by contact dermatitis of the scalp in patient 2, but not in the other patients. Vitiligo involved sites distant from the location of DCP application in 2 out of 4 patients Vitiligo as an Adverse Reaction to Topical Diphencyprone