Childhood dermatomyositis and polymyositis. Treatment with methotrexate and prednisone.

The conditions of three children with dermatomyositis and one child with polymyositis were treated for nine to 31 months with combined prednisone and intravenous methotrexate (1 mg/kg/wk) when prednisone alone was ineffective in controlling the disease or when there were substantial steroid-related toxic effects. All children showed a major clinical improvement within three months despite concomitant reduction of the prednisone dose. Three children completely recovered; one patient relapsed and died. The toxic effects of methotrexate included elevated liver transaminases (3/4), nausea (2/4), abdominal pain (2/4), bone pain (2/4), mild neutropenia (1/4), and mild pruritus (1/4). Intravenous methotrexate is an effective adjunct to steroid therapy in the treatment of steroid-resistant or life-threatening dermatomyositis-polyositis or dermatomyositis-polymyositis complicated by severe steroid-related effects.