Dipeptidyl peptidase 4 inhibitors linked Bullous Pemphigoid in Patients with Type 2 Diabetes Mellitus: A Series of 13 Cases

Abstract Background Dipeptidyl peptidase 4 (DPP4) inhibitors have increasingly been linked to bullous pemphigoid, but there is paucity of data from India where about 1.85 million patients have been estimated to use these drugs. Methods In 30,000 patients with T2DM seen by us in two tertiary care centres since 2015, we detected 13 cases of bullous pemphigoid linked to DPP4 inhibitors. We used WHO-UMC (World Health Organization-Uppsala Monitoring Centre) causality assessment system for assessment. Results Lesions of bullous pemphigoid appeared at varied intervals (within 1 weeks to 2 years) after start of DPP4 inhibitors. Implicated drugs were Linagliptin (n, 8), Vildagliptin (n, 4) and Sitagliptin (n, 1). Mostly, lesions were seen after 60 years age, and over trunk and extremities. Skin biopsy was compatible with bullous pemphigoid in two patients. Lesions regressed within a month of stopping DPP4 inhibitors in 9 patients while delayed regression up to 6 months in 4 patients. Overall, skin lesions remitted in all patients and did not recur. Conclusion Any new bullous lesion appearing while patient is on DPP4 inhibitors should be considered as bullous pemphigoid and should necessitate prompt withdrawal of the drug.