Once the emergency symptoms have been treated you will be instructed in medication to take for the next several hours to days to prevent the reaction from recurring. These severe allergic reactions can be life-threatening and require immediate medical treatment. The effects of hives can last from a few hours to several weeks or months. Hives will eventually clear without treatment, but taking drugs such as antihistamines or corticosteroids help the hives go away faster, treat the itch, and prevent new hive formation. Chronic urticaria last for a longer period.
Antihistamines are usually very helpful.
The hives resolve spontaneously after weeks or months but may recur off and on. Call the doctor or 911 at once if you have an allergic response that affects your breathing. You should also call if you continue to have outbreaks of hives. Take antihistamines or other medications to help relieve your symptoms. Be sure to ask your doctor or pharmacist about possible side effects or drug interactions.