Exfoliative dermatitis type of rash usually occurs between the 3rd and 7th day after the onset of the disease, can occur skin flaking and lead to epidermal peeling, especially in the palms of the hands and soles of the feet of the skin, is due to the drug-induced severe dermatitis manifested as a generalized redness and swelling of the skin, peeling with severe systemic symptoms. Most of them have the sex of causing drug rash, including herbs, but the antigenic strongest caused by the most. Mostly luminal, sulfonamides, pau tazone, sodium phenytoin, p-aminobenzoic acid, streptomycin, gold, arsenic and other heavy metals. Such as hydroxypyrazole pyrimidines, methoxythiophene cephalosporins, metformin, chloroquine, isoniazid, and thiosemicarbazones can also be caused. In addition, to suffer from congenital allergic diseases of the body and organs suffering from disease, the occurrence of drug rash sex is large. Most cases occur after long-term use of drugs. Clinically, we should be alert to the sudden onset of generalized, symmetrically distributed rashes in the course of treatment, inquire about the history of drug use, and pay special attention to cross-allergy to drugs and hidden forms of drug allergy. Familiarize yourself with the characteristics of various types of drug allergy and rule out similar medical and dermatological conditions. Usually drug rashes are brightly colored and itchy. Usually the rash improves and subsides quickly after discontinuation of the sensitizing drug. A drug history of drug rash occurring after drug use, disappearing after stopping the drug and recurring on reuse is diagnostic in clinical practice. Modern immune test methods such as lymphocyte transformation test, radioallergen adsorption test (RAST), basophil granulocyte degranulation test, macrophage wandering inhibition test, leukocyte histamine test, etc., can assist us in understanding the immune relationship between the drug and the organism, and have no practical diagnostic value.