[Pemphigus vulgaris induced by radiotherapy].

A 54-year-old male patient who had been suffering from lymphoma for four years developed pemphigus vulgaris three weeks after exposure to radiotherapy. Skin lesions were initially strictly confined to the irradiated area and later extended over other skin areas. The eruption rapidly improved with glucocorticosteroid therapy which could be stopped after six months. Thirteen cases of pemphigus following X-ray irradiation have been published, twelve of them being associated with an internal malignancy. Clinical data strongly indicate radiation therapy as a provoking factor for the development of pemphigus, but a possible role of the neoplasia in our patient cannot be ruled out. It is suggested that immunological disturbances associated with lymphoma lead to an autoimmune response after exposure to X-rays. Ionizing radiation may alter the antigenicity of the epidermal cell surface or unmask epidermal antigens.