Increased frequency of diabetes mellitus in patients with bullous pemphigoid: a case-control study.

A case-control study was designed to assess the occurrence rate of primary diabetes mellitus (DM) in patients with bullous pemphigoid (BP) by retrospectively reviewing the records of our thirty histopathologically and immunopathologically proved cases of BP from the past 10 years. One hundred twenty patients were selected as controls, which included two names immediately before and two names immediately after each case of BP in our histopathology record book. The occurrence rate of primary DM prior to the administration of systemic corticosteroids was significantly higher in patients with BP than in the controls (20% and 2.5%, respectively; p = 0.004). Among patients over 50 years of age, this occurrence rate was again higher in patients with BP than in the controls (23% and 3.6% respectively; p = 0.02). This study suggests a higher than chance association of BP and primary DM.