Concurrence of Bullous Pemphigoid and Psoriasis: A Case Report

Bullous pemphigoid (BP) and psoriasis are chronic recurrent inflammatory skin diseases. The pathogenesis of concurrence of BP with psoriasis is still unknown. A 39-year-old male with a five-year history of chronic plaque psoriasis developed itchy large tense bullae on the trunk and upper extremities after he had been receiving narrow band ultraviolet B (NBUVB) therapy over five months. Skin biopsy from bulla on the trunk showed typical histological features of BP. Direct immunofluorescent staining showed deposit of immunoglobulin G and C3 in the basement membrane zone (BMZ) which supported the diagnosis of BP. It has been postulated that the autoimmune process responsible for BP lesions might be induced by ultraviolet light therapy and/or the inflammatory processes that occur in psoriasis.