Sudden allergies on the face may be caused by sudden exposure to allergy-prone substances and a disruption of the immune system during this time, causing an acute allergic reaction. Allergic substances include strong sunlight as well as dust mites, powder mites, dust, mold and pollen. For sudden allergy on the face, it is necessary to stop using all cosmetics and avoid prolonged exposure to sunlight, and to avoid spicy and irritating diets such as raw onion, raw garlic, strong tea, coffee, mustard, chili, etc., and not to drink alcohol. Clinically, it is necessary to administer 200ml of compound glycyrrhizic acid monoammonium S sodium chloride injection once/day. And you can take levocetirizine hydrochloride capsule, loratadine citrate capsule or epinastine hydrochloride capsule orally, and you cannot apply drugs externally in the acute period.