The red rash of allergy to erythromycin is a medication rash, which needs to be treated in a timely manner in the hospital, applying medication and other symptomatic treatments. Drug rash, also known as drug dermatitis, is caused by the use of drugs caused by the skin and mucous membrane adverse reactions, manifested as a rash, itching, pain, hyperpigmentation and other symptoms. The prognosis of drug rash is related to the severity of the disease, patients need to go to the hospital in time, according to the specific conditions of the disease, symptomatic treatment. The first step in the treatment of drug rash is to stop using or replace the sensitizing drugs. For patients with mild disease, benadryl, vitamin C, prednisone and other drugs can be given for treatment, generally good prognosis; for patients with serious disease, often need to use high dose glucocorticoid intravenous drip, such as methylprednisolone, intravenous immunoglobulin and so on. The use of drugs should be carried out under the guidance of medical professionals to avoid adverse reactions.