There is no difference between urticaria and hives. Urticaria is a skin condition that causes intense itching and rapid development of raised, smooth patches of skin. It is commonly called hives, and is often the sign of an allergic reaction. This condition occurs most often on the face and trunk. Occasionally, the affected area extends to the throat and causes difficulty in breathing. In these severe cases, emergency injections of epinephrine or corticosteroids may be required.
Urticaria is characterized by an outbreak of red and white welts of varying size that appear suddenly either in small areas or all over the body. The welts often appear and disappear, lasting anywhere from a few minutes to a day or two. Sometimes, the outbreak can last for weeks. Acute urticaria lasts less than six weeks, while the chronic form lasts longer. Additional symptoms such as intense itching, fever, and nausea can accompany the hives.
This condition can be caused by an allergy to certain foods, particularly shellfish, strawberries, or tomatoes. Urticaria can also be a reaction to drugs, food dyes, or animal skin. Contact with certain plants, insect bites, and insect stings can also result in an outbreak. Cold weather, sunlight, and exercise have been known to cause urticaria and hives too. A predisposition to hives tends to run in families.
A diagnosis of urticaria is based on the observance of the symptoms. If a patient suffers repeated outbreaks of hives, his or her physician may need to perform allergy tests to pinpoint the cause. Allergy testing can be extensive and take time as suspected triggers are tested individually before they can be discounted. Eliminating many suspect foods and then reintroducing them one at a time sometimes helps to identify the cause.
The itching and welts of urticaria and hives are treated with antihistamines. When taken several times a day at a prescribed dosage, the correct type of antihistamine will help control swelling by preventing the released histamine from triggering the hives. Drowsiness and dry mouth are common side effects of antihistamines, so the type and dosage may need to be adjusted periodically to minimize discomfort. Serious urticaria outbreaks are sometimes treated with corticosteroids to reduce inflammation.
Prevention of urticaria and hives is accomplished by avoiding contact with the triggering substance or allergen. Sometimes, the triggering substances or allergens cannot be identified. Hives that develop from unknown causes are called idiopathic. Idiopathic urticaria can result in chronic episodes of itching and welts and may require regular treatment with antihistamines or a combination of antihistamines and corticosteroids.