The itching and redness of skin allergy is mainly allergic dermatitis, which needs to be relieved by oral anti-allergic drugs, topical anti-itching drugs and avoiding contact with allergens. 1. Anti-allergic drugs: skin allergies can take loratadine, cetirizine and other drugs to fight allergies, these are antihistamines, after taking the general half an hour to improve allergy symptoms, but may cause dizziness, drowsiness, nausea and other adverse reactions. 2. Anti-itching drugs: If the itching and swelling is obvious, you can use glycerite lotion to relieve discomfort, external application can be applied, there is no obvious adverse reaction; you can also use hydrocortisone butyrate ointment and other hormonal drugs, but it is not recommended to use for a long time, so as not to cause hormonal dermatitis, resulting in drug dependence. 3. Avoid contact with allergens: the most common allergens are cosmetics, pollen, animal fur, dust, etc. You can go to the hospital to do allergen testing to avoid re-exposure to allergens, which can reduce the chances of allergy from the source. It is recommended that allergic patients go to the dermatology department in time, avoid blindly using medication on their own, and do not scratch hard to avoid causing breakage and infection.