Three Cases of Bullous Pemphigoid Associated with Dipeptidyl Peptidase-4 Inhibitors - One due to Linagliptin

BACKGROUND: Bullous pemphigoid (BP) is an acquired subepidermal autoimmune blistering disease in which there are humoral and cellular responses against the BP180 and BP230 antigens. Dipeptidyl peptidase (DPP)-4 inhibitors enhance endogenous glucagon peptide-1 and glucose-dependent insulinotropic polypeptide secretion with food intake, which leads to insulin secretion, as well as to the reduction of glucagon secretion. Recently, several cases of DPP-4 inhibitor-associated BP have been reported. OBJECTIVES: To report 3 cases of DPP-4 inhibitor-associated BP, one of which is due to linagliptin use, as well as to review all currently published cases of DPP-4 inhibitor-associated BP. CASE REPORTS: Three patients diagnosed with BP at our department showed a clear temporal relationship between the introduction of DPP-4 for the treatment of diabetes and the onset of BP. One case was due to linagliptin use, while the other 2 cases were due to an association with vildagliptin-metformin use. CONCLUSIONS: This is the first report of linagliptin-associated BP. Furthermore, 2 other cases of vildagliptin-associated BP are reported.