The condition of red rash on the buttocks in hot weather is considered to be due to prickly heat, eczema, hives and other factors. It can be relieved by topical medication, oral medication and home care. 1. prickly heat: this belongs to the summer or hot and humid environment in the more common skin diseases, mainly and small sweat glands in the ducts of obstruction related to the diagnosis can be used externally with glycerine lotion, can play the role of itching and astringent, but also pay attention to the skin cooling and dry clean. 2. eczema: this is a chronic inflammatory itchy skin disease, may be due to contact with environmental or food allergens, after diagnosis, oral loratadine, cetirizine and other drugs to stop itching treatment, if necessary, add oral prednisone and other glucocorticoid intervention. 3. Urticaria: mainly due to contact with allergens, can be treated by applying glycerine lotion and oral loratadine and other drugs. At the same time, it is important to get out of the bad environment in time. Rash on the buttocks in the heat of the day is likely to have other causes, so it is necessary to do further examination with the doctor, and then do the treatment, the above drugs need to be used in accordance with the doctor’s instructions, do not blindly use drugs.