Effect of retinoic acid in lichen planus of the genitalia and perianal region.

Lichen planus of the male genitalia presents as multiple violaceous papules or discrete annular lesions on the glans or shaft of the penis. In female patients, whitish striae or "leukoplakia-like" patches are occasionally observed on the vestibulum or labia minora and bluish-white papules in the anal cleft or around the anus. Signs of lichen planus elsewhere on the body may be absent. As has been noted in lichen planus of the oral mucosa, lesions of the genitalia and perianal region tend to persist for years. Several therapeutic remedies have been tried with no material benefit. Only the more concentrated fluorinated local corticosteroids have appeared to cause resolution of the lesions, but the results are not permanent and recurrences are frequent as soon as the therapy is withdrawn. When retinoic acid is used in lichen planus of the skin or oral cavity, resolution has been observed (Gunther, 1971, 1972a, b, 1973). It was therefore proposed to study the effect of retinoic acid (vitamin A acid) on lichen planus lesions of the genitalia and perianal region.