Clinical features and outcomes of juvenile dermatomyositis and other childhood onset myositis syndromes.

The childhood myositis syndromes, primarily JDM, are relatively homogeneous diseases that have a good outcome in most cases, but are chronic, with poor outcomes, in a substantial number of cases. Because of the rarity of childhood myositis, and because there has not yet been a unified evidence-based approach to therapy, optimal treatment remains unknown. In clinic-based series the disease seems to be homogeneous but there are patients with rare clinical features, (e.g., cardiac, pulmonary, and neurologic disease), that impact prognosis. Racial, genetic, and other factors may lead to geographic variations in clinical presentations and outcomes, and perhaps further exploration of these influences will lead to a better understanding of the clinical features and outcomes seen in children. Our treatments are based on accumulated experience, but proper clinical trials have not been done. Ongoing registry studies, development of validated activity and damage assessment tools, large clinical trials, and continued investigation into the pathogenesis of the childhood myositis syndromes should lead to improved understanding and better treatments.