Hives (Urticaria)

In this very common disorder, red, itchy lumps, known as hives or wheals, develop on the skin. They sometimes have a white center of variable size, and they often join together to form large, irregular patches. The wheals may occur anywhere on the body.

Hives are sometimes triggered by an allergic reaction to a food such as shellfish, strawberries, nuts or food additives; or to a drug such as penicillin. Handling certain plants, particularly nettles, can also bring on the condition. In other people, wheals are raised simply when the skin is scratched or exposed to heat, cold, or sunlight. But in many cases it is impossible to discover what triggers the condition. Whatever the cause is, known or unknown, tension and stress of any kind usually make hives worse.

Usually, the condition clears up within a few hours and does not cause any other problems, but occasionally it may persist for days or months, even if it is treated.

Some people have a more distressing form of the disorder, called angioneurotic edema. In this condition, the tissues underlying the wheals swell, particularly on the face. In severe cases, the lips and skin around the eyes swell enormously. If the swelling spreads to the neck, breathing can become obstructed. Such cases are rare but serious, because it is possible to suffocate under these conditions. Very rarely, hives are part of a more serious disease, for example, systemic lupus erythematosus. In most cases, however, hives are irritating but harmless.

What should be done?

If your hives are due to a food allergy, you may be able to identify the food responsible, because wheals will appear within a few minutes of eating that food. Identification of plants or drugs responsible for the disorder is also usually simple. Wheals will appear when you start to take the drugs and clear up when you finish. But you may not be able to identify the food or substance to which you are allergic if, for example, it is a food dye added to a wide variety of foods. In that case, if the disorder is troublesome, you should consult your physician. He or she may recommend an exclusion diet or refer you to an allergy specialist for skin tests to identify the causative agent. However, if your lips and the skin around your eyes start to swell, see your physician immediately.

To control troublesome hives, the physician may prescribe an antihistamine. In severe angioneurotic edema, the doctor may inject steroids to reduce the swelling and eliminate risk of suffocation.