Dermatomyositis worsens to the most serious condition with severe skin lesions, muscle lesions involving the heart and respiratory muscles, etc., and heart failure and respiratory failure. Dermatomyositis is mostly slow onset, with a few acute onset. Clinical manifestations are dominated by skin and muscle lesions, and patients may have various types of rashes, such as Heliotrope’s sign, Gottron’s papules, cutaneous heterochromia, perinail capillary dilatation, and symmetrically fused purplish-red spots. Muscle lesions are often characterized by symmetrical proximal muscle weakness of the extremities, in addition to involvement of the scapular girdle muscle group, neck and throat muscle groups, and also involve the heart muscle, with palpitations (rapid heartbeat, often accompanied by panic), arrhythmia and even heart failure. Involvement of respiratory muscle groups such as diaphragm, intercostal muscles, etc. can occur respiratory weakness and respiratory failure. Some patients may even develop interstitial lung disease, myocarditis, malignant tumors and other complications. It is recommended that patients with dermatomyositis should consult the rheumatology and immunology department in time, and standardized treatment should be carried out under the guidance of doctors.