Urticaria is the medical term for hives. Urticaria usually appears as red bumps or round welts on the skin. They may be associated with episodes of lip, tongue, or face swelling, called angioedema. Individual urticarial welts can last anywhere from minutes to hours to days depending on the cause. They are extremely itchy but usually not painful. There are many causes of acute urticaria, such as antibiotic or other drug reactions, certain infections, food allergy, insect stings and environmental allergens such as pollen, dust mite or cat.
However, chronic urticaria, which is recurrent or daily hives, may last months to even years and often times have no identifiable source. There are a certain number of conditions that are known to cause chronic urticaria, such as autoimmune conditions and certain thyroid diseases, but these are not commonly found in most patients with chronic urticaria.
Depending on the patient’s history and symptoms, the workup for urticaria may involve skin testing for foods, stinging insects, and environmental allergens. Laboratory tests also depend on the patient’s history, but may include a complete blood count, liver function, thyroid studies and specific allergy markers (i.e. IgE).
Treatment of chronic urticaria can be frustrating at times for both the patient and the clinician because even a combination of several different medications may only lessen the severity or frequency of hives, but not lead to complete resolution. The mainstay of therapy is use of the “H1” histamine receptor blockers commonly called called antihistamines. These include Zyrtec (cetirizine), Xyzal (levocetirizine), Claritin (loratidine), Atarax (hydroxyzine) and Allegra (fexofenadine). Sometimes patients will require various combinations of antihistamines. In addition, an “H2-blocker” such as Zantac (ranitidine) or Pepcid (famotidine) may be used in conjunction. These block a second type of histamine receptor. Even with these combinations of antihistamines, some patients will still have problems with urticaria. In these instances, it may be necessary to use immunosuppressive agents, such as prednisone (for short term) or cyclosporine (for longer term).
More recently, the FDA approved Xolair (omalizumab) for use in chronic refractory urticaria. Xolair is a synthetic monoclonal antibody that blocks the IgE antibody. IgE is an antibody that is part of your immune system and is responsible for allergic responses in your body. Xolair is a subcutaneous injection that one would receive every 4 weeks in the physician’s office. It has been shown in several scientific studies to significantly decrease severity of urticaria, even after the first dose.
It is important to remember that a rash of any kind, especially one that is chronic, should be evaluated by a physician.