Sudden allergy on the face may be caused by exposure to some external allergens, resulting in a certain inflammatory reaction on the face, and some people may also experience certain redness, swelling and itching. In this case, first of all, anti-allergy treatment is needed, local topical application of chlorcyclizine cream or topical application of benadryl cream can be applied temporarily. In addition, glucocorticoid creams, such as hydrocortisone butyrate cream, can be applied topically. If there is a significant exudative reaction, sometimes a cold compress of 3% boric acid solution is required. In addition, oral antihistamines, such as second-generation antihistamines, levocetirizine hydrochloride, loratadine, etc., can be administered orally. While using these medications, you need to pay attention to avoid using hot water or cosmetics to continue to stimulate, and also try to avoid eating spicy, stimulating food.