Urticaria, commonly called hives, is an inflammation of the surface layers of the skin, and is characterized by small, itchy red or white welts (called wheals). Urticaria is usually caused by an allergic reaction; however, the allergenic trigger is often unknown. When a cause can be identified, it is frequently something taken by mouth, such as shellfish or other fish, dairy products, peanuts or other legumes, chocolate, fresh fruit, or medications. Sometimes other allergens such as pollens, molds, or animal dander, can produce hives. Hives can also be caused by heat (cholinergic urticaria or "prickly heat"), cold (cold urticaria), pressure (dermographism and pressure urticaria), light (solar urticaria), exercise, and certain infections such as ]]>hepatitis B]]> .

In most acute cases, urticaria disappears within hours or days without any treatment. Sometimes, however, it may continue for a prolonged period, or recur frequently. Such chronic cases are often very difficult to treat.

Urticaria is closely related to another condition called angioedema, which involves swelling in the deeper layers of the skin. When swelling occurs in the throat or tongue, angioedema can be life-threatening.

Urticaria and angioedema are also closely related to anaphylaxis, an extremely dangerous condition that can lead to death within minutes or hours. Anaphylaxis is an overwhelming allergic reaction that may lead to swelling of internal organs, collapse of blood circulation, shock, or suffocation. It may be caused by all the same factors that trigger hives; one of the most well-known causes is bee sting allergy.

Conventional treatments for urticaria and angioedema include avoidance of triggering factors, and use of antihistamines, and, occasionally, corticosteroids. When breathing is threatened, epinephrine shots and possibly hospitalization may be needed.


Proposed Treatments for Urticaria

Sublingual Immunotherapy (SLIT)]]> has shown some promise for treating urticaria caused by latex allergies, in one small double-blind, placebo-controlled trial. ]]>6]]>

Based on the theory that urticaria may be caused by delayed type ]]>food allergies]]> , food allergen elimination diets have been tried as a treatment for chronic symptoms. However, the evidence that it works remains highly preliminary at best. ]]>1-3]]> See the ]]>Food Allergy]]> article for more information.

There are many forms of the elimination diet. One of the most common involves starting with a highly restricted diet consisting only of foods that are seldom allergenic, such as rice, yams, and turkey. Other proponents of the elimination diet allow a greater range of foods at the outset. If dietary restriction leads to resolution or improvement of symptoms, foods are then reintroduced one by one to see which, if any, will trigger urticaria. (For more information see the article on ]]>Food Allergies]]> .)

In China, urticaria is often treated with ]]>acupuncture]]> ; however, the evidence that acupuncture works for this condition is far too weak to rely upon at all. ]]>5]]>

Vitamins ]]>C]]> and ]]> B 12]]> , and the flavonoid ]]>quercetin]]> , have also been suggested, but there is no evidence as yet that they really work for treating urticaria.