Dermatomyositis and polymyositis

Dermatomyositis (DM) and polymyositis (PM) are currently considered to fall within the category of autoimmune diseases. DM manifests as diffuse inflammation of the skin and muscles, with erythema and edema on the skin, and weakness, pain, and swelling in the muscles, which may be accompanied by arthralgia and damage to multiple organs such as the lungs and myocardium; PM has no skin lesions. This disease is similar to muscular bi syndrome or rheumatic bi syndrome in traditional Chinese medicine.