Abstract
Eosinophilic granulomatosis with polyangiitis (EGPA) is a rare autoimmune disorder characterized by necrotizing vasculitis, asthma, and eosinophilia. We report a case of EGPA that developed during benralizumab treatment for severe asthma and provide a literature review. A 79-year-old Japanese male with severe asthma presented with generalized purpura 4 months after initiating benralizumab treatment. He had reduced his oral prednisolone dose from 7.5 to 2 mg/day. Laboratory tests revealed eosinophilia, and skin biopsy showed vasculitis with eosinophilic infiltration. He was diagnosed with EGPA and treated with corticosteroids, azathioprine, and mepolizumab, which led to rapid improvement and sustained remission. Five cases of EGPA developing during benralizumab treatment have been reported, with onset ranging from 14 to 36 weeks after initiation. Clinicians should monitor for EGPA development in patients receiving benralizumab, particularly during oral corticosteroid reduction.