Relapsing eosinophilic myositis.

We report 3 male patients with a unique eosinophilic myositis of unknown etiology who appear to have a benign course. The most striking feature in 2 patients was relapsing myalgias with lower extremity predilection and tendency for spontaneous recovery. Laboratory studies showed peripheral eosinophilia, elevated CPK, and EMG consistent with a myositic pattern. Muscle biopsies showed myositis characterized by focal necrosis and degeneration with an inflammatory infiltrate predominantly composed of histiocytes and eosinophils. Skin and fascia were normal.