Dermatomyositis is a relatively common skin disorder. Typical symptoms of dermatomyositis include two aspects, a skin symptom such as rash and a muscle symptom such as muscle weakness. 1. Skin symptoms: Typical skin lesions include to the positive rash, i.e., periorbital red or purplish-red macular rash, often accompanied by edema, photosensitive rash on the head, face, chest and V-zone (V-shaped sign) and back of the shoulders (shawl sign); Gotton rash, i.e., purplish-red papules on the elbows of the limbs, knees, metacarpophalangeal joints, and extensor surfaces of the interphalangeal joints. Mechanic’s hand, i.e., the skin on the radial palm surface of both hands appears keratinization, cracks, rough and flaky skin; perinail lesions, i.e., capillary dilatation erythema or petechiae can be seen at the nail root folds, and the others are skin atrophy, hyperpigmentation or loss of pigmentation, capillary dilatation or subcutaneous calcification. 2. Muscle symptoms: the main manifestation is the pain and weakness of limb muscles, especially near the trunk part of the muscles. Muscle tissues such as limb muscles, neck muscles, larynx, swallowing muscles, respiratory muscles, etc., will undergo inflammation and degeneration, which will eventually cause symmetrical muscle weakness and muscle atrophy. If dermatomyositis is diagnosed, it is recommended to seek medical attention to avoid delays.