Marked improvement of Churg–Strauss syndrome neuropathy by intravenous immunoglobulin and cyclophosphamide

A 42-year-old Japanese man developed Churg–Strauss syndrome 7 years after being diagnosed with chronic eosinophilic pneumonia. Prominent eosinophilia, subcutaneous nodules, and neuropathy in the left leg were seen. A pathological diagnosis of necrotizing vasculitis was determined by a biopsy of a subcutaneous nodule. The leg pain was severe and there was prominent atrophy of the thigh and calf, but the muscle weakness was mild. Serum anti-myeloperoxidase anti-neutrophil cytoplasmic antibody was positive. Because the initial treatment with an intravenous methylprednisolone pulse at 1 g/day for 3 days was not sufficient, a onetime treatment with intravenous cyclophosphamide at 15 mg/kg and intravenous immunoglobulin therapy (IVIG) at 400 mg/kg/day for 5 days were administered. Peripheral eosinophilia improved and the leg pain significantly improved. IVIG was repeated 1 month later and symptoms gradually improved further. The early diagnosis of Churg–Strauss syndrome and the early initiation of IVIG with cyclophosphamide were thought to be important.