[Successful early use of mepolizumab in eosinophilic granulomatosis with polyangiitis presenting with peripheral neuropathy and gastrointestinal bleeding].

We report a case of a 55-year-old male with eosinophilic granulomatosis with polyangiitis (EGPA) presenting with peripheral neuropathy and gastrointestinal (GI) bleeding. Despite initial treatment with high-dose intravenous methylprednisolone and intravenous immunoglobulin, the patient's symptoms persisted, and GI bleeding worsened. Capsule endoscopy revealed multiple ulcers and erosions throughout the small intestine, and biopsies from the ileum, cecum, and skin showed marked eosinophilic infiltration. Although peripheral blood eosinophil counts were normalized, tissue eosinophilia remained evident. Early administration of mepolizumab, an anti-IL-5 monoclonal antibody, led to rapid improvement in both GI bleeding and neuropathic symptoms. This case highlights the potential role of tissue-infiltrating eosinophils in EGPA pathogenesis and suggests that mepolizumab may be effective even when blood eosinophil levels are not elevated. Early intervention with mepolizumab may be beneficial in severe or refractory EGPA cases with GI involvement, which are associated with poor prognosis and high relapse rates. Careful monitoring and timely therapeutic decisions are essential for improving outcomes in such patients.