Topical imiquimod-induced linear IgA bullous dermatosis

A 68-year-old woman was referred to the unit of dermatology for a large basal cell carcinoma on the chin. She was treated with imiquimod cream 5%, and 4 weeks after she developed isolated and grouped tense serum-filled vesicles and bullae on lips, nose, scalp, ankles and lumbar area, and then expanded to the whole body. Histological examination was consistent with a subepidermal bullous dermatosis. Moreover, direct immunofluorescence showed linear deposition of IgA at the basement membrane zone supporting the diagnosis of linear IgA bullous dermatosis (LABD). Dapsone 50 mg/day was administered, and the lesions gradually improved within some weeks, and no new lesions appeared. The temporal relationship between the application of the drug and the development of the disease indicates a role of this topical agent in triggering LABD.