Bullous pemphigoid: a cause of peripheral blood eosinophilia.

A retrospective study demonstrated that fourteen of twenty-eight patients (50%) with clinical, histologic, and immunofluorescent findings of bullous pemphigoid had peripheral blood eosinophilia. Blood eosinophilia ranged from 5% to 43% when first tested, with increase in one patient to 56% during treatment. The pathophysiologic cause of blood eosinophilia in bullous pemphigoid is discussed with its relationship to previously demonstrated elevations of IgE and eosinophilic chemotactic factor of anaphylaxis (ECF-A) in serum and blister fluid. Peripheral blood eosinophilia was a common finding in our group of patients, and bullous pemphigoid should be included in the differential diagnosis of bullous skin conditions with eosinophilia.