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. The following diseases may also be the cause of total epidermal necrosis and subepidermal maculoplasia: 1. Epidermolysis bullosa “epidermolysis bullosa” (EB) was first introduced by Koebner in the late 19th century to describe a blistering skin disease that does not leave a scar. It was subsequently used to describe a group of polygenic genetic dermatoses characterized by susceptibility of the skin and mucous membranes to mechanical injury and the formation of large blisters, a typical group of diseases involving the basement membrane area of the skin. Internal organs may also be involved. The disease shows great clinical variability. Also, genetic heterozygosity is evident, with autosomal dominant and recessive inheritance. Abnormal wound repair can lead to chronic damage and crusting, and metastatic carcinoma is common. Significant progress has been made in the study of this disease, mainly through molecular cloning of the key protein networks that encode the structural integrity of the skin hierarchy. This disease also belongs to the category of “pemphigus” in Chinese medicine. 2, acquired epidermolysis bullosa Acquired epidermolysis bullosa (EBA) is a chronic subepidermal maculopathy with immunoreactive antibodies against type VII collagen, mostly seen in adults. The disease is similar to the “pemphigus” described in the Chinese medical literature.