[A case of pemphigus vulgaris with predilection for exposed areas]

A 35-year-old man with the bullous lesions on the face and forearms was reported. Histopathological studies revealed the presence of acantholysis. Direct immunofluorescent (DIF) investigation showed depositions of IgG and C3 in the intercellular space of the epidermis. While the patient was successfully treated with oral prednisolone, we tried to induce the lesion by applying middle wave ultraviolet (UVB) on the uninvolved skin of the back. After irradiation of 5 MED of UVB, deposition of IgG in the intercellular space of the epidermis corresponding to the irradiated region was revealed by DIF, but no acantholysis was observed. When the serum which had been taken before the corticosteroid administration was injected on the uninvolved skin of the back followed the irradiation of the same dose of UVB, upper dermal infiltration of neutrophils was observed in addition to the above findings. The results indicate that the possible relation between UVB and production of the lesions was not obtained, however, in view of the clinical distribution of the lesions and IgG deposits by the irradiation of UVB, we should consider the relation between pemphigus vulgaris and the light.