Ulcerative colitis and bullous pemphigoid: Direct association or a medication side effect: A case report

Bullous pemphigoid (BP) is an autoimmune blistering skin disorder. It is associated with other autoimmune disorders and the use of certain drugs. We describe a case of BP in a patient with ulcerative colitis (UC) treated with mesalamine.

A 38-year-old male patient with UC and a history of multiple flares was maintained on mesalamine with good clinical response. One year after starting mesalamine, he sought medical care following the onset of a severe itchy rash of several weeks' duration with a recent appearance of skin bullae. A biopsy of the skin revealed subepidermal blistering dermatitis with focal eosinophilic spongiosis. Direct immunofluorescence studies revealed linear IgG and C3 immune reactant deposits at the dermoepidermal junction, consistent with the diagnosis of BP. Prednisone therapy alleviated his symptoms. However, tapering prednisone led to re-eruption of the bullae.

BP should be considered when patients with UC develop skin manifestations. Although BP is not one of the extraintestinal manifestations of UC, there may be an association between these two conditions. Whether treatment with mesalamine or other therapeutic agents plays a role in the development of BP remains unclear.