Dermatomyositis.

Dermatomyositis is a condition that combines an inflammatory myopathy with characteristic cutaneous disease. This disorder is closely related to polymyositis, which has all the muscular features of dermatomyositits without the presence of skin disease. Both dermatomyositits and polymyositis may occur in the presence of other collagen vascular diseases such as lupus erythematosus, scleroderma, Sjögren's syndrome, rheumatoid arthritis, and various vasculitides. Dermatomyositis seems to be characterized by an increased frequency of internal malignancy and both dermatomyositis and polymyositis are associated with morbidity and mortality. Therefore, prompt and aggressive therapy is necessary.