Skin allergies such as redness, swelling and other manifestations mostly occur after contact with allergens, should actively search for allergens, remove from the allergic environment, topical drugs or oral medication. The causes of skin allergy are very complex, after the occurrence of allergy, as far as possible to find the cause of the allergy, out of the allergic environment, and avoid scratching to avoid triggering infection. In addition, if the localized allergy, you can apply topical medication, when the redness and swelling is obvious, you can use glycerine lotion to stop the itching, and at the same time, you can apply glucocorticosteroids locally, such as dexamethasone acetate ointment, dinexed ointment, etc. to control the local inflammation; itching is obvious, it is recommended to take oral antihistamine medication, such as chlortetracycline, cetirizine and so on. Skin allergy redness and swelling should be timely to the hospital, under the guidance of the doctor’s medication.