Redness and swelling of the skin after allergy can be treated by daily care, cold compress and medication. 1. daily care: avoid re-exposure to suspected allergenic substances, can use water to wash the affected area, avoid the use of irritating toiletries, so as not to aggravate allergies. 2. Cold compresses: cold towels or ice packs can be used to apply cold compresses to the affected area, which can effectively promote the contraction of capillaries, thus having a positive effect on the elimination of redness and swelling of the skin after allergy. 3. Drugs: If the swelling can not be reduced for a long time, you can choose to use doxepin hydrochloride cream, flufenamic acid butyl ester ointment and other drugs, which can promote the recovery of the local skin, if accompanied by itching symptoms, you can choose to use hydrocortisone butyrate cream, mometasone furoate cream, oral clonidine and other drugs for treatment. When taking medication, you need to standardize the use under the guidance of a professional physician, and remember not to blindly use medication to avoid adverse reactions and aggravate the skin.