Itchy red welts on the skin are referred to as hives, or urticaria. These welts are usually raised from the skin and can vary in size. Hives may occur independently or in groups of several welts. They usually occur as a result of an allergic reaction and, according to the American Academy of Dermatology, approximately 10 to 20 percent of people will experience hives at some point during their life.
Physiology
When you have an allergic reaction, the immune system triggers an inflammation response that involves the release of a chemical substance called histamine into the bloodstream and skin. Hives develop when the skin becomes inflamed and blood plasma travels through openings in the cells that line the small blood vessels in the skin. The inflammation associated with hives usually disappears within 24 hours, according to the American Academy of Dermatology.
Causes
Some of the most common causes of the development of hives include certain foods, medications and other allergens, such as dust and pet dander, according to the Mayo Clinic. Hives can also develop when you are exposed to extreme temperatures, emotional stress or strenuous exercise. Occasionally, hives occur as a result of an abnormal response to antibodies due to autoimmune disorders.
Complications
Although most cases of hives are minor, if the red welts develop in the mouth or throat, it can result in difficulty breathing, loss of consciousness or anaphylactic shock, which is a serious allergic reaction that can be life-threatening. Hives that develop around the eyes, lips or genitals may also cause excessive swelling.
Treatment
Treatment for hives usually consists of identifying the source of the reaction and eliminating contact with it. Antihistamines may be helpful in reducing the release of histamine and easing symptoms. Antihistamines are available over-the-counter or in prescription strength. Topical creams may also reduce the itching associated with hives. If the allergic reaction is severe, an injection with epinephrine, or adrenaline, may be necessary.
Considerations
A specific type of hives, called chronic urticaria, can last more than six weeks. According to the American Academy of Dermatology, this type of urticaria occurs in only a small percentage of people. The cause of chronic urticaria is often difficult to diagnose. Those with the condition usually must undergo a full medical evaluation that includes a review of medical history, physical examination and various medical questions intended to pinpoint the underlying cause.
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