Psoriasiform pemphigus foliaceus: a report of two cases.

Pemphigus foliaceus (PF) represents an autoimmune blistering disease characterized by the disruption of epidermal intercellular adhesion proteins. Clinical findings include superficial crusted erosions in a seborrheic distribution; however, the disease can rarely present as an exfoliative erythroderma. Histopathologic findings include acantholysis with cleavage within the granular layer. Direct immunofluorescence studies show intercellular IgG and complement deposition. We present two patients, to our dermatology department, with a previous diagnosis of psoriasis, with an exfoliative erythroderma, which ultimately proved to be because of PF based on histopathological features, direct immunofluorescence results and levels of antibodies against desmoglein 1. Both patients responded well to oral prednisone and rituximab. This variant of PF should be entertained in both the clinical differential diagnosis of psoriasiform erythroderma and in the microscopic differential diagnosis of psoriasiform epidermal hyperplasia with focal acantholysis, particularly in patients for whom the clinical history is not classic for psoriasis or for whom conventional psoriasis therapies have not proven beneficial.