Gliptin-Induced Bullous Pemphigoid: A Case Series

Abstract Bullous pemphigoid (BP) is a chronic autoimmune blistering disorder characterised by tense bullae and intense pruritus. Dipeptidyl peptidase-4 (DPP-4) inhibitors are widely used to manage type 2 diabetes mellitus. In recent years, multiple studies have recognised DPP-4 inhibitors as causative agents for drug-induced BP. This series includes two patients who developed BP after starting Sitagliptin therapy and a third who developed the condition following the initiation of Vildagliptin. It highlights distinct clinical courses: a 75-year-old male with Sitagliptin-induced BP who exhibited a refractory course requiring Omalizumab despite stopping the drug; a 73-year-old female with Vildagliptin-induced BP characterised by rapid onset within 15 days; and a 55-year-old female with Sitagliptin-induced BP presenting with mucosal involvement and clear dose-related worsening. Immunological profiling revealed isolated anti-BP180 positivity in all cases, with histology showing a subepidermal cleft with eosinophilic infiltrates, and direct immunofluorescence showing linear C3 and IgG deposition in one case. Clinical improvement was observed after stopping the inciting gliptin and starting systemic therapy tailored to disease severity. All patients showed a gradual decrease in blister formation and symptomatic relief following these interventions. This series highlights that gliptin-induced BP is not a uniform condition; it can present with variable latent periods, atypical mucosal involvement, and varying degree of reversibility. Pharmacovigilance is crucial, as early detection, discontinuation of the drug, and appropriate therapy are vital for improving clinical outcomes and preventing disease progression.