Risk factors for bullous pemphigoid in the elderly: a prospective case-control study.

A rise in the incidence of bullous pemphigoid (BP) was documented recently in Europe, and the main risk factors for BP remain unknown. We conducted a multicenter case-control study to evaluate risk factors for BP. We identified 201 incident BP cases and 345 controls individually matched for age, gender, center, and place of residence (home, nursing home, or extended-care facility).