Eosinophilc polymyositis.

A case of eosinophilic polymyositis is reported. Tender muscle swelling was followed by proximal weakness, creatinine kinase elevation, and electromyographic features typical of polymyositis. Severe myocarditis, pericarditis and heart failure were present. Muscle biopsy specimen showed active myositis with eosinophil infiltrate. Unlike previous cases, blood eosinophils count was normal. The clinical response to corticosteroids was excellent, and a relapse occurring as steroid dose was lowered responded rapidly to an increased dose of prednisolone. Eosinophilic polymyositis may be a component of a general systemic illness with prominent cardiac involvement.