Dermatomyositis is classified as adult dermatomyositis, childhood dermatomyositis, malignant tumor dermatomyositis, autoimmune disease secondary dermatomyositis, non-myopathic dermatomyositis and multiple dermatomyositis. 1. Adult dermatomyositis: patients with symmetrical proximal limb muscle weakness, pain as the main characteristics, but also appear dermatomyositis characteristic rash, manifested as periorbital edema-like erythema, V-collar sign, batch sign and so on the rash, and joints will appear scaly rash. 2. Malignant tumor-phase dermatomyositis: Generally speaking, the tumor is solid tumor, such as lung cancer, breast cancer. 3. Dermatomyositis in children: Dermatomyositis in children usually has a more rapid onset of disease, with more obvious symptoms of myxedema and muscle pain, and is often accompanied by vasculitis. 4. Autoimmune diseases secondary to dermatomyositis: due to the body’s immune system disorders, the skin and muscle as a foreign body to attack. 5. Dermatomyositis without myopathy: it is a dermatitis with skin damage, but it is also accompanied by the incidence of malignant tumors. The main symptoms are erythema of the skin in the exposed area and pulmonary lesions. 6. Multiple dermatomyositis: a non-purulent inflammatory disease in which the transverse muscle is the main lesion. Its clinical manifestations are weakness of proximal muscle groups, skin rashes on the palms and elbows and other parts of the body. If suffering from dermatomyositis, it is recommended that patients go to the regular hospital in time. Drugs need to be taken under the guidance of the doctor, usually can be appropriate exercise, as far as possible to avoid the recurrence of the disease.