The redness, swelling and itchiness of a plastered allergy is considered to be caused by contact dermatitis or drug dermatitis due to skin irritation caused by the drug or material of the plaster. You need to immediately remove the cream, stop using the medication, and then use water or soapy water to wash off the medication site, wash off the residual medication, which can help relieve the redness, swelling and itching symptoms, usually mild allergy symptoms can be self-healing after a period of time. For patients with persistent local redness, swelling and itching, you need to actively seek medical advice and choose appropriate medication for treatment under the guidance of a doctor. 1, topical medications: boric acid solution, glycolic acid lotion, triphala lotion, etc. can be used for wet compresses, but also corticosteroid hormone drugs, such as mometasone furoate cream, dextran cream, hydrocortisone butyrate cream and other topical applications, with anti-allergic, swelling and anti-itching effect; 2 Some patients can be treated with oral anti-allergy drugs along with topical drugs, which can help relieve the symptoms of allergic redness, swelling and itching after applying the cream. Commonly used drugs include loratadine tablets, cetirizine hydrochloride tablets, epinastine hydrochloride tablets, etc. Corticosteroids can also be used for treatment, such as prednisone acetate tablets, etc. In addition, you should keep the local skin clean and avoid scratching to cause rash breakage and infection. Drink more water, eat a light diet, and avoid spicy and irritating foods.