If the symptoms of allergic rashes are mild, they can usually be cured in a week or so after stopping the medication. But if the symptoms are serious, you need to take medication, otherwise it may lead to aggravation of the condition. If the phenomenon of long red rash after plaster, should be promptly removed from the body of the plaster, and the use of warm water to rinse to remove the residue of the plaster, the general rash can subside within a week on its own. If the rash phenomenon is serious, you can follow the doctor’s instructions to take antihistamines such as loratadine tablets, chlorpheniramine tablets and other relief, you can also take vitamin C tablets at the same time. When the itching is severe, you can also apply antipruritic agents, such as glycerine lotion and so on. If the ointment allergy rash, you should go to the hospital in a timely manner, under the guidance of the doctor standardized treatment, do not self-medication.