Understanding Hives

Approximately 20 percent of the U.S. population gets hives, also called urticaria, at least one time in their life. Hives are red, swollen welts and can appear anywhere on your body. They are sometimes itchy. Hives can last anywhere from a few minutes to several weeks, however, each individual welt should disappear within 24 hours.

Causes of Hives

Usually, hives are caused by an allergic reaction to either a drug or certain foods. If you have other allergies, you are more likely to get hives. For some, the cause of the hives is obvious. An allergic reaction to certain foods, such as peanuts or shellfish, may cause hives within minutes or hours of eating the food.

In other cases, the cause is not so obvious. Some of the other reasons hives may occur are:

Insect bitesAllergies to pollen, animals, latex or other substancesInfections and illnesses, such as thyroid disease or hormonal problemsSun exposure or exposure to heat or coldStress

You may need to work closely with your doctor to determine the cause of your hives.

Diagnosing the Cause of Hives

If you have one episode, your doctor probably will not dig too deep to find out what caused the hives, however, if you have chronic hives, he may refer you to an allergy specialist for testing. In addition to taking a detailed medical history, the specialist may request the following:

Details on substances in your home and work environmentA list of all medication you are taking, including vitamins, over-the-counter medications and supplementsLab tests, including blood or urine analysisAllergy skin testing

There are many possible causes of hives. According to the American College of Allergy, Asthma and Immunology, approximately 20 percent of all cases of hives can be attributed to a specific cause. The other cases either require testing and research or will never be known.

Treatment

Many cases of hives need no treatment at all. The red welts often disappear on their own, sometimes within minutes or a few hours. If your hives are itchy, cool compresses or taking a cool shower will often relieve the itch. Antihistamines may also be recommended to control the allergic reaction and to reduce the itchiness.

If you have more than one episode or if you have chronic hives (lasting more than six weeks), the best treatment is to find the cause and avoid the triggers. For some people, a daily dose of antihistamine is needed to help control the hives. Because some antihistamines can make you drowsy, it is important to talk with your doctor about the different antihistamines and their side effects. Your doctor may also recommend cortisone treatment or other medications that reduce inflammation.