Bullous pemphigoid in a patient treated with UVA-1 phototherapy for disseminated morphea

Bullous pemphigoid is an autoimmune disease of the skin characterized by th e production of antibodies directed at structures of the basement membrane zone (BMZ) leading to subepidermal blisters. Several causative triggers hav e been described in the literature, among them UV light. Here, we report on a 73-year-old Caucasian female with disseminated morphea who developed bli sters on her extremities after receiving whole-body UVA-1 phototherapy. The initial differential diagnosis of a phototoxic versus photoallergic reacti on was ruled out as the lesions continued to spread after discontinuation o f phototherapy. Histological and direct immunofluorescence examination show ing a subepidermal blister and linear IgG deposits along the BMZ along with detection of circulating anti-BMZ antibodies led to the diagnosis of bullo us pemphigoid. Immunosuppressive therapy resulted in regression of all blis ters. After ruling out other possible causes, such as neoplasias or drugs, we conclude that UVA-1 has to be regarded as the most likely trigger of the disease. Copyright (C) 2001 S. Karger AG, Basel.