A case of bullous pemphigoid provoked by doxycycline-induced phototoxicity.

Bullous pemphigoid (BP) is an autoimmune subepidermal blistering disease caused by autoantibodies directed against BP antigen 180 or BP antigen 230.1 BP is histopathologically characterized by a superficial dermal eosinophil-rich infiltrate with dermo-epidermal junction (DEJ) detachment. On direct immunofluorescence linear deposition of immunoglobulin G (IgG) and/or complement component 3 (C3) is present at the DEJ. Predisposing factors are broad and include human leukocyte antigen genes, aging, and trigger factors such as drugs, ultraviolet (UV) radiation, trauma, surgical procedures, and infections.