Diagnosis

Your doctor will ask about your history of allergic reactions, and about your recent exposure to pets, plants, insects or new foods or medications. During a physical examination, your doctor usually can distinguish between hives and other types of skin rashes. Also, he or she will check for other signs of a serious allergic reaction.

If the condition occurs frequently, your doctor may order blood tests or perform skin testing for allergies. If your doctor suspects that you are undergoing anaphylaxis, he or she will begin treatment immediately and closely monitor your blood pressure and breathing.

Expected Duration

Individual hives usually fade within eight to 12 hours, but recurrent hives can continue to reappear for weeks or months. In cases of chronic urticaria (hives), the condition may last for six months or more.