Relapsing eosinophilic perimyositis.

Two patients with a syndrome of relapsing myalgia are described. In both cases nonspecific inflammatory features were present and electromyography disclosed a myositic pattern in one. Muscle biopsy in both patients showed a perimysial infiltrate of eosinophils although peripheral eosinophilia was only noted in one patient. In each, relapse occurred after a recovery phase, but eventually recovery was complete, spontaneously in one, and after therapy in the other. The known causes of eosinophilic myositis are reviewed, with emphasis on a companion with the myositis of eosinophilic fascitis (Shulman's syndrome). Because our cases exhibited distinctive features, this new syndrome should be considered in the differential diagnosis of any eosinophilic myositis.