Etanercept-induced generalization of chronic, localized, anogenital bullous pemphigoid in a psoriatic patient

BP: bullous pemphigoid DIF: direct immunofluorescence TNF-a: tumor necrosis factorealpha INTRODUCTION Up to 20% of cases of bullous pemphigoid (BP) show an atypical presentation, exhibiting localized distribution or non-bullous lesions, such as eczematous, urticarial, prurigolike, and erythema multiformelike papules and plaques. These atypical presentations can be associated with a delay in diagnosis and thus require a high degree of suspicion. We present a case of recalcitrant BP localized to the anogenital region with subsequent generalization after administration of etanercept, a tumor necrosis factorealpha (TNF-a) inhibitor. Our review of bibliographic databases did not find any cases with similar distribution and course. TNF-a inhibitors are used in the treatment of pemphigus and pemphigoid. With expanding use of TNF-a inhibitors and longer follow-up periods, there are increasing reports of autoimmune diseases associated with these therapies, including autoimmune bullous disease and systemic lupus erythematosus. This case highlights that caution should be exercised when considering antieTNF-a therapy for autoimmune bullous diseases.