Linagliptin-Induced Bullous Pemphigoid: A Case Report and Comprehensive Literature Review.

Bullous pemphigoid (BP) is an autoimmune blistering disorder predominantly affecting the elderly, presenting significant management challenges, especially in patients with multimorbidity and polypharmacy. This report details a complex case of a 94-year-old woman with new-onset BP following dipeptidyl peptidase-4 (DPP-4) inhibitor (linagliptin) initiation, complicated by diabetes mellitus, chronic kidney disease, hypertension, and dementia. We describe her clinical course, therapeutic challenges, and response to systemic corticosteroids combined with topical therapies. Furthermore, we comprehensively review the current evidence for emerging biological and targeted therapies (e.g., rituximab, dupilumab, omalizumab, and intravenous immunoglobulin) in BP management, highlighting their potential role in reducing corticosteroid dependence and improving outcomes in frail, comorbid patients. This case underscores the importance of the prompt recognition of drug-induced BP, individualized treatment plans considering comorbidities, and the growing promise of novel therapeutic strategies.