[Pigmentation abnormalities in the course of topical immunotherapy of alopecia areata].

Pigmentation troubles have been associated in the past years with contact dermatitis and patch-testing. Contact allergy and increase of pigmentation has been associated with Tinopal; on the other hand contact allergy and depigmentation have been associated with many substances such as DNCB, squaric acid dibutylester (SADBE), carbyne, alstroemeria. Leukoderma can also be produced by irritant compound such as phenols, catechols and mercaptoamines. During 1978 and 1984 we have treated 132 patients suffering from alopecia areata with DNCB or SADBE: 51 patients have been treated by DNCB and 81 by SADBE. During the treatment 10 patients developed a leukoderma vitiligo-like localized to the areas of topical application of the allergens and to the flare-up site; one patient had an increase of pigmentation. Lesions vitiligo-like appeared 10-15 weeks after the onset of treatment. Among the patients who developed leukoderma, 4 had a personal history of vitiligo. The possible pathogenetic mechanisms are discussed.