Eosinophilic Granulomatosis with Polyangiitis (formerly Churg-Strauss Syndrome)

Idiopathic vasculitis of small- and medium-sized arteries seen in patients with symptoms of asthma

Affects multiple organ systems, most commonly skin and lung, but heart, gastrointestinal tract, and peripheral nerves may also be affected

Marked peripheral eosinophilia

Chest radiographic findings range from transient opacities to pulmonary nodules

Histologic features include fibrinoid necrotizing epithelioid and eosinophilic granulomas

Usually requires corticosteroids (prednisone, 1 mg/kg/day, tapering over 3–6 months) and cyclophosphamide (1–2 mg/kg/day, until complete remission is obtained and then tapered slowly)

Replace cyclophosphamide with methotrexate or azathioprine for maintenance therapy