Six Cases of Pemphigoid Nodularis during Treatment with Dipeptidyl Peptidase-4 Inhibitors

Introduction: We investigated 6 cases of pemphigoid nodularis under treatment with dipeptidyl peptidase-4 (DPP-4) inhibitors. Case Representation: In 3 cases, only nodules were observed at the initial presentation, but bullous lesions appeared during the course of the disease. All patients had diabetes mellitus and were taking DPP-4 inhibitors from 1 to 1.5 years. Anti-BP180Nc16a antibodies were positive in 3 cases, and low or negative in 3 cases. Full-length BP180 antibodies were analyzed in 2 of the 6 cases and were positive in both. Since patients with diabetes mellitus occasionally develop prurigo nodularis, it is important not to misdiagnose pemphigoid nodularis as prurigo nodularis. Conclusion: There are few reports of pemphigoid nodularis under DPP-4 inhibitors. It should be noted that not only bullous pemphigoid but also pemphigoid nodularis can be induced by DPP-4 inhibitors.