Ultraviolet-induced acantholysis in pemphigus.

Ultraviolet irradiation produced an acantholytic phenomenon in normal skin of seven patients with pemphigus foliaceus. In six of the seven patients, this reaction was manifested by a positive Nikolsky sign and was confirmed by biopsy in four. Friction alone, infrared irradiation, occlusive dressing, and a rubefacient failed to produce a similar reaction. The thermal burn in the skin of patients having pemphigus was of subepidermal type. Ultraviolet-induced acantholysis was inhibited by chloroquine phosphate, taken orally, in the two patients tested. Prednisone had no such effect. It is concluded that ultraviolet light is a major aggravating stimulus for pemphigus foliaceus.