Total epidermal necrosis and subepidermal macules are one of the symptoms of toxic necrotizing epidermolysis bullosa drug rash. Most drugs have the potential to cause drug rash, including herbal medicines, but those with stronger antigenicity cause the most. Most of them are sulfonamides, salicylates, antipyretic and analgesic drugs such as pautazone and aminopyrine, phenolphthalein, penicillin, tetracycline, barbiturate, phenytoin sodium, etc. In addition, the risk of drug rash is higher in organisms suffering from congenital allergic diseases and in patients with diseases of vital organs. Adverse reactions of skin and/or mucous membrane damage caused by drugs used for prophylaxis, diagnosis, and treatment, regardless of the route of entry into the organism, are called drug rash. It is a common condition in dermatological emergencies. Toxic epidermal necrotizing drug rash is a serious skin disease with multisystem damage. It is characterized by a large area of damage and a high mortality rate. Symptoms and diagnosis: Rapid onset, accompanied by high fever, irritability, drowsiness, convulsions, coma and other obvious signs of systemic toxicity. Skin manifestations include total epidermal necrosis and subepidermal blister formation. At the beginning, it is a large bright red patch, followed by purple-brown, and within 1 to 2 days, large blisters appear on the patch and expand, partially synthesizing several dozens of centimeters in size, showing most parallel strips of crepe. Nilolsky’s sign (j), while the mucosa of the mouth, eyes, nose, upper respiratory tract, pubic area, and esophagus, can be widely involved. The mucosa is detached and a large vesicular surface appears. Pain is extreme. The body temperature often remains above 40°C for 2 to 3 weeks. The heart, kidneys, liver and brain are also often involved. The prognosis is serious, with a death rate of 25% to 50%. Most deaths are due to secondary infections, liver and kidney dysfunction, and water-electrolyte disturbances. Diagnostic history: the use of sulfonamides, salicylates, antipyretic analgesics such as pautazone and aminopyrine, phenolphthalein, penicillin, tetracycline, barbiturates, phenytoin sodium and other drugs. Instrumental examination: Microscopic examination of skin smear, physical examination of skin diseases.