Successful Treatment of Coexisting Alopecia Areata and Bullous Pemphigoid With Dupilumab: A Case Report

ABSTRACT Alopecia areata (AA) and bullous pemphigoid (BP) are distinct autoimmune diseases, but growing evidence points to overlapping immune pathways. We present a rare case of a 71‐year‐old woman with concurrent AA and BP. She initially presented with 10 months of progressive scalp and body hair loss (Severity of Alopecia Tool [SALT] ~ 80) and nail dystrophy; scalp biopsy confirmed AA. One month later, she developed pruritic vesicles and papules, with biopsy findings consistent with BP. Despite multiple therapies, including systemic and topical corticosteroids, anthralin and topical ruxolitinib, she remained refractory. Dupilumab was initiated, resulting in marked improvement: her SALT score dropped to ~5, BP resolved and nails improved. After 1 year on dupilumab, she remained lesion‐free with complete hair regrowth and was able to discontinue treatment without relapse. This case highlights the immunological interplay between Th1‐ and Th2‐mediated disease pathways and the evolving therapeutic role of interleukin (IL)‐4/IL‐13 blockade. Although traditionally associated with Th1 dominance, AA may involve Th2 pathways, particularly in atopic patients. Dupilumab, an IL‐4Rα antagonist, has shown emerging utility in AA and was recently FDA‐approved for the treatment of BP. This case illustrates dupilumab's potential as a unifying therapeutic in autoimmune conditions with overlapping inflammatory mechanisms and underscores the need for further research to guide individualized immunomodulatory therapy in complex dermatologic diseases.