Urticaria (hives) is an outbreak of red bumps or patches called wheals that appear on the skin, produced by the presence of histamine, and are brought on by a trigger.  The most likely causes of acute (sudden) hives are an allergy to foods, insect sting, or medication reaction.  In children, viral infections such as a cold can also trigger acute hives.  Some other triggers of hives are sudden temperature change, emotional stress, and even pressure on the skin.   Chronic urticaria is defined as hives lasting for more than 6 weeks.  Triggers of most chronic hives are difficult to identify.  In 7 of 10 chronic urticaria cases no triggers can be identified.

Chronic Idiopathic Urticaria (CIU), also called chronic spontaneous urticaria, is defined by itchy hives that last for at least six weeks, with or without angioedema (swelling), and no apparent external trigger.  CIU is the most common form of urticaria, attributable to more than 50% of cases.  Chronic Idiopathic Urticaria can be a frustrating disorder to treat, as it often can last anywhere from 1 to 5 years and can even persist beyond five years in 11% to 14% of patients.  Most CIU occurs between the ages of 20-40, and women are twice as likely to have CIU as men.

A subset of patients with CIU (30-40%) has been classified with autoimmune urticaria.  This form is identified on the basis of two main findings: the association with thyroid autoimmunity and the presence of anti-IgE and/or anti-IgE receptor antibodies.  These patients may have a link to thyroid dysfunction, particularly Hashimoto’s Thyroiditis, an autoimmune cause of hypothyroidism.

Histamine release from cutaneous (skin) mast cells has long been associated with the pathogenesis of urticaria, whereas in some patients with Chronic Idiopathic Urticaria, IgE, IgE receptor, and autoantibodies also play an important role in triggering chemical mediator release.   Non-sedating H1-antihistamines are the current mainstay for initial treatment.  Treatment options for patients who do not respond to H1-antihistamines include the use of H2-antihistamines (Zantac or Targement), leukotriene-receptor antagonists (Singulair) or even systemic glucocorticoids, cyclosporine, hydroxychloroquine, dapsone or methotrexate for severe refractory chronic idiopathic urticaria.  The effectiveness of these treatments is unpredictable and also includes potential long-term side effects.

In the past few years, new treatments targeting IgE have been developed as a result of breakthroughs in genetic engineering and an overall better understanding of the IgE and IgE receptor role in chronic idiopathic urticaria.  Xolair (omalizumab), a humanized monoclonal antibody, bonds with circulating IgE and the IgE receptors and blocks the initiation of an allergic reaction and chemical mediator release.  With this treatment, patients receive an injection once every two to four weeks.  Such breakthrough treatments have given new hope to patients with severe Chronic Idiopathic Urticaria.

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