What are hives?

 • Hives, known medically as urticaria, are very common.

• They are reddish, itchy swellings called “wheals” that last for a few hours before fading away. New ones may develop as old ones fade. When hives are forming, they usually are very itchy and they may also sting.

• They arise from the chemical histamine that is released in the upper layers of the skin.

• Sometimes there may be deep swelling (angioedema) around the eyes, lips, and tongue.

• Hives may be classified as acute or chronic.

• Acute hives last for fewer than 6 weeks.

• Chronic hives last longer than 6 weeks.

 What causes acute hives?

 • There may be an obvious cause such as a viral infection, a reaction to a drug, or an insect bite.

• The most common drugs that may cause acute hives are antibiotics (especially penicillin and sulfa drugs), pain medications (such as aspirin and ibuprofen), narcotics, radiocontrast dyes, diuretics (“water pills”), and opiates (such as codeine).

• The most common foods that are associated with hives are milk, wheat, eggs, chocolate, shellfish, nuts, fish, and strawberries. Also, food additives and preservatives such as salicylates and benzoates may be responsible.

• Very often a definite cause is never found.

• Very rarely, a severe life-threatening allergic reaction known as anaphylaxis, which requires immediate medical attention, can occur.

 What causes chronic hives?

 • The cause is usually unknown; however, chronic hives may, very infrequently, be a sign of an underlying illness.

• In 85% to 90% of patients, the cause is unknown.

• Emotional stress may trigger recurrences.

• Chronic hives also may be caused by physical stimuli such as pressure, cold, heat, sunlight, or exercise. Such hives are called physical urticarias.

 What should be done to determine the cause?

 • Tell your health care provider about all of the medications (including oral contraceptives) and vitamins that you are taking.

• Unfortunately, most of the time routine blood tests are of little or no value in determining the cause.

• Allergy testing is expensive, and often tests are positive for allergies that have nothing to do with hives.

What can be done to treat and prevent them?

• If possible, the cause of the hives should be found and eliminated.

• The mainstay of treatment for chronic hives is the use of oral antihistamines.

• Systemic steroids (cortisone) are sometimes used for short periods to “break the cycle” of chronic hives.

• People with severe reactions should consider wearing a medical alert bracelet that describes their problem.

• Aspirin-containing compounds, ibuprofen, and narcotics, which are all histamine-releasing agents, may aggravate both acute and chronic types of hives. They should be avoided.

• Tight clothing and hot baths and showers should be avoided, particularly in people who have a physical urticaria.

• If all else fails, a diary of daily foods eaten may be kept, followed by elimination of foods and food additives. This is rarely successful.

Fortunately, most cases of chronic hives go away with or without treatment.

50% are free of hives after 3-12 months

20% are free of hives after 12-36 months

20% are free of hives after 36-60 months

A very small percentage has it for up to 25 years!