Itchy arm allergy can be considered as eczema, which may also occur clinically as erythema, papules, oozing, redness and swelling. Treatment can be oral levocetirizine hydrochloride tablets, olopatadine hydrochloride tablets, loratadine tablets or epinephrine hydrochloride tablets, and topical application of mometasone furoate cream, or hydrocortisone butyrate ointment. If the rash is large and severe, a strong hormone halometasone ointment may also be used. If the redness and swelling is severe and the exudation is high, it can be treated with a fixed dose of compound glycopyrrolate monoammonium S chloride. At the same time, it is necessary to avoid spicy and irritating food, as well as beef and mutton, seafood and other hairy products, prohibit alcoholic beverages, and prohibit the use of salt water, alcohol, vinegar and other external washing.