Urticaria (hives) are localized, pale, itchy, pink wheals (swellings) that can burn or sting. They may occur singularly or in groups on any part of the skin; they are part of an allergic reaction and are very common. Approximately 10-20 percent of the population will have at least one episode in their lifetime. Most episodes of hives disappear quickly in a few days to a few weeks. Occasionally, a person will have them for many months or years. New hives may develop as old ones fade. Hives can vary in size form as small as a pencil eraser to as large as a dinner plate, and may join to form even larger swellings.
Hives are produced by blood plasma leaking through tiny gaps between the cells lining small blood vessels in the skin. Histamine is a chemical released from cells in the skin called “mast cells” which lie along blood vessels. Allergic reactions, chemicals in foods, or medications may cause hives; sometimes it is impossible to find out the cause. When hives form around the eyes, lips, or genitals, the tissue may swell excessively. Although frightening, the swelling usually goes away in less than 24 hours. Severe cases of hives may cause difficulty in breathing or swallowing and emergency room care is required.
The best treatment for urticaria is to find and eliminate the cause whenever possible. Antihistamines are prescribed to provide relief and work best if taken on a regular schedule to prevent hives from forming. There are many antihistamines available. No one antihistamine works for everyone. The dermatologist may use combinations to control the urticaria. In severe cases, an injection of epinephrine (Adrenalin) may be needed. Cortisone may also bring dramatic relief, but its use must be limited to short periods of time.