Urticaria (hives) are red, very itchy, swollen areas of the skin. Angioedema is swelling of the deeper layers of the skin. Urticaria and Angioedema may appear together or separately on the body. Urticaria arises suddenly and may leave quickly in 1-2 hours, or can last as long as 24 hours. They often appear in clusters, with new clusters appearing as other areas clear.
At some time in their lives approximately 20% of the people in the U.S. will develop urticaria and/or angioedema involving various parts of their body. In 90% of cases these problems last six weeks or less and then disappear on their own. In the rest of the cases the problem lasts over six weeks and then the problem is called “chronic”. At this point various tests are usually ordered, though about 90% of cases the cause of the urticaria is still unknown. Even in those cases where urticaria and angioedema lasts more than six weeks, the problem will usually go away on its own and almost always disappears within12 months. Even though the cause cannot be found in 90% of cases, by using medications the urticaria and angioedema can be prevented. Studies of urticarial patients show that if the hives can be controlled for three month, then in most cases the medications can be gradually reduced and the hives not return.