The most likely reason someone has chronic urticaria is that their body is making autoantibodies, resulting in mast cell and basophil activation, which then results in the release of histamine, causing hives. According to various studies, the number of cases of chronic urticaria that are indicated as autoimmune ranges from around 25% to as high as 76%. Generally, most reports claim around 30 to 50% of chronic hivers are autoimmune. So far only two of the autoantibodies have been identified:
- most commonly, autoantibodies against the high-affinity IgE receptor FcεR1
- autoantibodies against IgE
The remaining 50% of CU patients generally are still diagnosed as idiopathic. However, researchers believe there are other as-yet-undetermined autoantibodies causing CU, so the number of cases that turn out to be autoimmune will probably rise as further research is done.
Diagnosing autoimmune chronic urticaria is still not easy to do. Currently, we know of two tests that are available, but only a few doctors and labs seem to be able to perform them at this time, and neither test is 100% accurate. The first test, called the autologous serum skin test, involves taking a sample of the patient’s blood, separating the serum, and then injecting the serum back into the patient. Two control injections, one of saline and one of histamine, are also given at the same time. A positive reaction for autoimmunity is a wheal/flare response from your own serum, no response from the saline, and a wheal/flare from the histamine. The other test is the basophil-histamine release test, which is a blood test run in a lab. Other testing methods are being investigated.
In our urticaria support group, we have observed some patterns that are indicative of autoimmunity. Also, some patterns are seen in other autoimmune diseases, and some have been observed in formal research studies. If you experience any of these, they may be clues that your chronic urticaria is autoimmune:
- You have a personal history of other autoimmune disease
- Your family has a history of autoimmune disease (not necessarily chronic urticaria)
- Your mother had endometriosis, and/or if you are a woman, you have had endometriosis
- You are female
- You have autoimmune thyroid disease
- Your symptoms worsen during your monthly cycle (women only)
- Your symptoms lessen or go into remission during pregnancy
- You have experienced remissions in the past
- Symptoms began following an ‘event’ that triggered the immune system, such as accident, illness, surgery, infection, allergic reaction
- Prior to developing CU you would describe yourself as someone who was rarely ill; and even now you seldom catch colds and flu, even if everyone around you is coughing and sniffling
Treatment of autoimmune CU begins the same as for any CU—H1 and H2 antihistamines. Autoimmune CU is often resistant to this treatment, however, and may require immunosuppression. Corticosteroids such as prednisone may be given, but some doctors and researchers find that it is not a good long-term treatment for CU. There is also a chance that a rebound effect may occur, where the hives return—sometimes worse than ever—when the steroids are discontinued. Cyclosporine has been shown in several studies to be fairly effective. Dr. Malcolm Greaves (a leading researcher and authority in chronic urticaria) has noted in an unpublished observation that in confirmed cases of autoimmune CU, “at least 75% of treated patients experience total or almost total remission.” He further notes that 1/3 of those patients remain in remission, 1/3 have a mild relapse, and the remaining 1/3 relapse severely following withdrawal of the cyclosporine (1). Other immunosuppressants have been tried and are being further investigated, such as Imuran and Cytoxan. There are further treatment options as well, such as intravenous immunoglobulin (IVIG) and plasmapheresis.
(1) —Malcolm Greaves. “Chronic Idiopathic Urticaria.” 2003. Curr Opin Allergy Clin Immunol 3(5):363-368.http://www.medscape.com/viewarticle/461843
Greaves, Malcolm W. and Kaplan, Allen P., eds. 2004. Urticaria and Angioedema. Marcel Dekker Co.
Shomon, Mary. July 7, 2003. “Chronic Hives Linked to Autoimmune Thyroid Disease.” http://www.thyroid-info.com/articles/hives.htm