Unfamiliarity of physicians with chilblains (perniosis) gives rise to unnecessary hospital admissions with expensive laboratory and radiologic evaluations and, at times, hazardous therapy. Seven cases of chilblains were seen in San Francisco from November 1986 through January 1987. The patients presented with pruritic, at times painful, purple acral patches or plaques on the fingers, toes, and nose after exposure to a cool or a cold, damp environment. Histologic examination in two cases revealed a perivascular lymphocytic infiltrate with endothelial swelling of the subcutaneous fat and of the upper and lower dermal plexus.