Coexistence of generalized pustular psoriasis and bullous pemphigoid: Pathogenic relationship or coincidence?

The Gulf Journal of Dermatology and Venereology ABSTRACT Psoriasis vulgaris and bullous pemphigoid represent two clinically well-characterized, chronic, inflammatory skin diseases. The concomitant occurrence of these two entities in a patient is rare, and the exact nature of this relationship is not clear. We describe a 31-year-old woman with a history of plaque-type psoriasis who presented with generalized pustular psoriasis after which she developed dessiminated vesiculobullous lesions. Skin biopsies showed the typical histologic and immunohistochemical traits of bullous pemphigoid. Bullous pemphigoid is the autoimmune blistering disease that has most often been associated with psoriasis. The pathogenic relationship between psoriasis and bullous pemphigoid is unclear. It has been postulated that the autoimmune process responsible for bullous pemphigoid lesions may be induced by ultraviolet light therapy, topical corticosteroids, and/or the inflammatory processes that occur in psoriasis.