Familial lichen planus.

Familial lichen planus (FLP) was observed to have developed within a period of 3 years in 2 sisters as well as in the son of one of the women. In contrast to typical FLP, the eruption was generalized in only 1 of these patients; no atypical forms were observed; the response to topical treatment with steroids was rapid, and the relapses were few and mild. Previous reports of familial cases of lichen planus as well as the long interval between onset of the disease in the affected members of the family speak in favor of a genetic predisposition. HLA typing revealed HLA DR in all 3 patients. There was no increased incidence of HLA B7, HLA A3 or HLA A28.