Also known as drug rash, it is an acute rash reaction caused by the systemic use of drugs (oral, injection, infusion, etc.). Drugs that can cause drug rash are many, the more common are antibiotics (penicillin and ampicillin, etc.), antipyretic and antigout drugs (anacin, aspirin, carbamazepine, allopurinol, etc.), sedative-hypnotic (chlorpromazine, phenobarbital), sulfonamides (sulfamethoxazole, furazolidone, etc.), as well as serum products, and so on. Its pathogenesis is divided into immune or non-immune two, the immune response includes all I, II, III, IV type of allergic reaction. In Chinese medicine, it is called: “Chinese medicine poison”. [Diagnosis] 1. Medical history: a clear history of drug use in the recent past before the onset of the rash. The interval between the use of the drug and the rash (incubation period) has a certain regularity. If it is the first time to use the drug, often for 4-20 days, the average 8-9 days. If the drug is used again and has been sensitized to it, the onset of the disease often occurs within 24 hours. The incubation period of exfoliative dermatitis is usually more than 3 weeks. 2, clinical manifestations: the rash often simulates other rash infectious diseases or common skin diseases. However, the rash is more widely distributed, more numerous, more colorful, and more symmetrical. Often accompanied by fever and other systemic symptoms. In severe cases, there may be damage to internal organs such as the heart, liver, kidneys, etc. and/or hematopoietic system. General skin manifestations include: (1) fixed-type drug rash: one to several round red spots, clear boundaries, heavy blisters, leaving obvious pigmentation spots after healing; lesions often occur in the same place, such as lips, fingers and toes joints. (2) Scarlet fever or measles-like: the onset and development of the rash is more rapid, soon spread throughout the body. (3) Urticaria or angioedema. (4) Erythema multiforme: in severe cases, the mucous membranes are involved and there is high fever, which is severe erythema multiforme. (5) Herpetic epidermal necrolysis and laxity type: rare, but serious, for large or multiple loose blisters, often involving the eyes, mouth and external genitalia and other mucous membrane areas, the onset of 3~4 days began to epidermal laxity. (6) exfoliative dermatitis type: rare, but heavy duchess, early to diffuse erythema, oozing; later to repeated flaking. (7) Other types: such as pityriasis rosea-like, allergic purpura-like, eczema-like, erythema nodosum-like, cutaneous vasculitis, photosensitive reaction, drug lupus, acne-like, nail plate lesions, skin pigmentation or hypopigmentation, itchy skin. 3, the course of the disease is often self-limiting, generally 2 ~ 4 weeks can be cured, but the exfoliative dermatitis type is often in 1 ~ 3 months or longer to be cured. 4, with fever and other systemic symptoms, white blood cell count and classification can be increased, but neutrophils are not high, eosinophil absolute count is often increased. Liver and renal function measurements, electrocardiogram and lung radiographs are abnormal in severe cases. [Differential diagnosis] 1, rash infectious diseases (such as scarlet fever, measles) and rash-type drug rash; the former before the onset of no history of drug use but have a history of contact with infectious diseases, the rash color is darker, itching is lighter, the systemic symptoms are heavier, there are infectious diseases characteristic of the course of the disease and the symptoms and signs, such as measles Koplik spots and Kartak symptoms, scarlet fever, the strawberry tongue and the perioral pale circle, etc.; 2, with the common dermatoses (such as urticaria, polyposis, pityriasis rosea, allergy), the skin is not as clear as in other cases, and the skin is not as dark. 2, and common skin diseases (such as urticaria, erythema multiforme, pityriasis rosea, allergic purpura, etc.): the latter onset of the history of drug use, there is a primary dermatologic disease, unlike drug rash after stopping the faster improvement or subside. The distribution of the rash is not as extensive and symmetrical as the drug rash, and the color is not as bright as the drug rash. 3. Genital herpes, chancre and fixed-type drug rash: no history of medication before the onset of the disease, a history of unclean sexual intercourse, an incubation period characteristic of the disease, and laboratory tests are helpful. 4, herpetic epidermal necrolysis loosening type of drug rash and herpetic disease: the latter slower onset, gradually aggravated. The history is long and the rash is scattered. Pathology, direct and indirect immunofluorescence tests help in differential diagnosis. [Treatment] Principle: stop using all suspected pathogenic drugs, including some drugs with similar structure to suspected pathogenic drugs; drink more water to promote drug excretion; early and adequate anti-allergic treatment. 1, Chinese medicine treatment: Chinese medicine believes that this disease is due to endowment intolerance, food taboos, embedded dampness heat sensory poison, dampness and heat toxicity in the skin caused by. In severe cases, toxic heat into the camp, can lead to qi and blood burnt. Chinese medicine diagnosis of this disease: (1) damp-heat sensing poison type: the treatment is appropriate to remove heat and dampness, cool blood detoxification; the formula is to remove heat and dampness soup plus subtraction. (2) poison into the camp blood type: treatment is appropriate to clear heat and cool blood detoxification; formula with detoxification and cool blood soup plus reduction. (3) internal use of proprietary Chinese medicines, such as flower snake capsule. (4) local external use of compound 1 lotion, red sea stone lotion, ice yellow skin music ointment, Huanglian moist muscle cream. 2, Western medicine treatment: A internal treatment: (1) mild condition of 1 ~ 2 antihistamine drugs as appropriate (such as rash-like drug rash). (2) the condition is more serious and the etiology is clear need early systemic application of glucocorticosteroid hormone therapy to control allergic reaction caused by inflammation of the skin mucous membrane and other organs damage.