The redness, swelling and itching of plaster allergy is considered to be contact dermatitis, you should stop plastering, clean the drug with water, if necessary, topical medication or oral medication. 1. stop using the medicine: plaster allergy red swelling and itching, is considered to be allergic to some of the ingredients in the plaster or adhesive tape, should immediately stop using the medicine, will be torn off the plaster in a timely manner. 2. Cleaning: After tearing off the plaster, you can wash the allergic parts, you can use soap and water, you can also use flowing water to wash down the residual drugs on the skin. 3. medication: if the symptoms are more serious can also use glycerine lotion coated, you can also choose glucocorticoid drugs, such as hydrocortisone cream, dexamethasone cream, severe oral antihistamine drugs, such as cetirizine, loratadine. Ointment allergy red swelling and itching can not be treated casually, if you need to use drugs, should strictly follow the doctor’s instructions to avoid adverse reactions.