Anti-neutrophil Cytoplasmic Antibody-negative Eosinophilic Granulomatosis with Polyangiitis Complicated with Peripheral Neuropathy that Underwent Remission Induction with Mepolizumab Monotherapy.

A 72-year-old woman was admitted to our hospital with numbness in her lower extremities and hypereosinophilia. She was diagnosed with eosinophilic granulomatosis with polyangiitis (EGPA). On admission, she was suspected of being complicated with pneumonia and sepsis; therefore, treatment with mepolizumab monotherapy was begun, resulting in partial improvement. After the possibility of a complicating infection was ruled out, corticosteroids were initiated, followed by intravenous gamma globulin therapy. Although the induction of remission of EGPA with mepolizumab monotherapy is not usually recommended, induction with mepolizumab monotherapy may be an option in terms of safety and clinical efficacy in some cases.