Dermatomyositis is an auto-immune disease, consisting of an idiopathic inflammatory myopathy with characteristic cutaneous findings.

This systemic disorder most frequently affects the skin and muscles but may also affect the joints, the esophagus, the lungs, and less commonly, the heart.

Severe dermatomyositis is associated with profound muscle weakness with involvement of the lungs and heart which may if uncontrolled cause death.

The prevalence of dermatomyositis is estimated to be 20-100 per million individuals.