Allergic to ointment on the arm should be washed off the ointment, stop using the drug, and promptly go to the hospital dermatology department. Arm ointment allergy may appear localized skin redness, swelling, rash, pain, itching and other uncomfortable symptoms, the above situation should be immediately wash the ointment, remove the ointment, temporarily stop using the ointment, and promptly go to the hospital dermatology consultation, may be taken to reduce the amount of drug, stop or change the drug and other treatments. Some of the topical skin medications such as retinoic acid drugs itself may be irritating, can cause local skin peeling, tingling, etc., sometimes mistaken for allergies, but more tolerable, and with the use of drugs the skin can gradually tolerate, consult a doctor can generally continue to use under the guidance of a doctor. In addition, topical drugs should be used under the guidance of a doctor to avoid blind use of medication, randomly increase the dose, etc., to avoid the occurrence of adverse reactions.