Dipeptidyl peptidase-4 (hereinafter referred to as DPP-4) inhibitors are used in diabetes therapy. They lower blood glucose by inhibiting DPP-4 and promoting insulin secretion. Here, we report a case of oral mucous membrane pemphigoid caused by the oral administration of a DPP-4 inhibitor. A 61-year-old female with gingival erosion and bleeding in the maxilla from the right first premolar to the left first premolar was referred to our department. On the first visit, redness, blisters, erosion, and the Nikolsky phenomenon were observed in the aforementioned region. A biopsy was performed for suspected pemphigoid. A histopathological
diagnosis of pemphigoid was obtained using HE staining and the fluorescent antibody method. The patient had diabetes and had been taking a combination drug containing vildagliptin (DPP-4 inhibitor) and metformin hydrochloride for two years and six months. We suspected that the pemphigoid was caused by the DPP-4 inhibitor. A request for a prescription modification was made to the internal medicine department, and the DPP-4 inhibitor was replaced with canagliflozin hydrate. The symptoms (redness, blisters, erosion, and the Nikolsky phenomenon) disappeared one month after suspension of the drug containing the DPP-4 inhibitor. Furthermore, relapse has not occurred in the 2 years since.
