A large, red and itchy patch on the body is a condition that could be an allergic reaction to the area. This allergy could be urticaria or contact dermatitis. For this condition, anti-allergy treatment is generally needed first. Localized lesions can be temporarily treated with topical application of glyburide lotion to stop the itching. If the effect is not obvious, you can also apply topical hydrocortisone butyrate cream or topical compound camphor cream, dampicol cream, etc. These can be. In addition, oral antihistamines can be taken to relieve itching, such as levocetirizine hydrochloride, loratadine, epalrestine, etc. Oral antihistamines of the first generation, such as paracetamol or ketotifen, can also be taken as appropriate. If the erythema is infectious, such as due to soft tissue skin infection. Although it is sometimes itchy, anti-infection treatment is needed and can be accompanied by appropriate oral antibiotics, such as oral cephalexin, etc.