Coexistence of pemphigus foliaceus and bullous pemphigoid. Demonstration of autoantibodies that bind to both the pemphigus foliaceus antigen complex and the bullous pemphigoid antigen.

Pemphigus and bullous pemphigoid are autoimmune blistering diseases of the skin characterized by circulating autoantibodies directed against the keratinocyte cell surface and the epidermal basement membrane zone, respectively. The coexistence of pemphigus and bullous pemphigoid is very uncommon. We describe a patient with pemphigus foliaceus who later developed bullous pemphigoid and show, by means of immunoprecipitation studies utilizing both cultured keratinocytes and suction blister epidermis, that our patient had circulating autoantibodies directed against both the pemphigus foliaceus antigen complex and the bullous pemphigoid antigen. This report is the first to demonstrate the coexistence of pemphigus foliaceus and bullous pemphigoid at the molecular level.