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Asthma Specialists JEFFREY TULIN-SILVER, M.D. ~ SUCHETHA KINHAL, M.D. BOARD CERTIFIED ADULT & PEDIATRIC ALLERGY, ASTHMA & IMMUNOLOGY www.michiganfoodallergy.net Comprehensive Food Allergy Clinic of West Bloomfield
Suite 110 West Bloomfield, MI 48322 Phone: 248.932.0082 Fax: 248.932.0182 www.michiganallergy.com
Sublingual immunotherapy (SLIT) is a treatment that addresses the underlying cause of allergy. Allergy drops containing the specific allergens that one is allergic to are placed under the tongue ("sublingual"), and then swallowed 30-60 seconds later. These allergens interact with special immune cells under the tongue, and with repeated administration of these antigens, the immune system's reactivity to these allergens is reduced ("desensitization"). Sublingual immunotherapy (SLIT) is very much like allergy injection therapy (AIT), in that both treatments modify the primary abnormality in allergic disease - the immune system's over-reactivity to allergens such as pollen, dust mite, animal dander, etc. What are the advantages of SLIT versus allergy injection therapy? Allergy injection therapy has been administered as an effective treatment for over 100 years, and its clinical effectiveness in treating nasal allergy, allergic asthma and stinging insect (venom) allergy is well documented. SLIT is not considered more effective than AIT, but because SLIT is much less likely to cause adverse reactions, it is beneficial and recommended for the following conditions:
Sublingual immunotherapy is easy and convenient. Because the safety profile of sublingual immunotherapy is excellent, after the first dose is administered in the doctor's office, the remaining doses can be self-administered at home. You do not have to drive to the doctor's office and then wait 30 minutes after the shot to make sure there is no reaction. Because you have your allergy vaccine with you, you do not have to worry about being late for a shot. Adherence to the dosing schedule ("patient compliance") is therefore quite high. How does sublingual immunotherapy work? SLIT is given as drops that are placed under the tongue, containing allergens to which the patient has documented sensitivity (grass pollen, dust mite, cat dander, etc). Antigen is placed on the mucosal surface under the tongue, allowing the allergen to interact with immune cells called dendrites. These dendrites then interact with specific white blood cells that migrate to regional lymph nodes which in turn interact with antigen-specific lymphocytes to induce allergic desensitization. SLIT has a good safety profile because the oral mucosa is exposed to numerous non-pathogenic antigens such as foods and resident bacteria on a daily basis. As a result, the sublingual mucosa has few pro-inflammatory cells, such as mast cells (which trigger allergic reactions in the nose and lungs). Allergy injections are administered into the skin and subcutaneous tissue, which has many more pro-inflammatory, mast cells. This helps to explain why SLIT, when compared to allergy injection therapy, is much less likely to cause a severe, generalized reaction. Clinical efficacy of sublingual immunotherapy SLIT has been in practice for almost forty years, primarily in Europe. Between 1990 and 2005, more than 40 controlled trials with sublingual inununotherapy were published in peer-reviewed journals. Most of the trials have confirmed the clinical efficacy of SLIT in allergic diseases caused by tree, grass and ragweed pollen, certain molds and dust mites. Today in Europe, SLIT accounts for 40 percent of allergy treatment. In 1998, a panel of experts of the World Health Organization, based on an extensive review of the literature, concluded that SLIT could be a viable alternative to allergy shots. In 2001, this statement was again confirmed in a position paper of the European Academy of Allerology and Clinical Immunology. In that same year, the Allergic Rhinitis and its Impact on Asthma extended the indications to children. In 2003, the Cochrane Collaboration, a highly-respected international organization dedicated to reviewing healthcare treatments, reviewed 22 randomized, double-blind, placebo-controlled studies involving 979 patients. Clinical trials ranged from six months to more than one year. Overall, there was a significant reduction in both symptoms (p<0.02) and medication use (p<0.03). No attempt was made to compare SLIT with AIT (allergy injection therapy). In 2006, the results of three large, double-blind, placebo-controlled trials with grass pollen were published. These trials, which included more than 1600 patients, showed a 35 to 40% reduction in clinical symptoms in the first year of treatment. A total of 82% of patients receiving active therapy reported feeling better after two years. Adverse effects associated with sublingual immunotherapy The most common side effect of SLIT is a local irritation in the mouth and under the tongue. Itching in the mouth also occurs on occasion, but this itching is usually transient and does not progress to a severe allergic reaction such as anaphylaxis. Very few patients cited local irritation or itching as a reason for withdrawing from the several clinical trials noted above. Other local, inftequent side effects included itching of the ear lobes and throat. If bothersome, these side effects were easily managed with oral antihistamines. In more than 20 years of clinical experience with sublingual immunotherapy. only 3 cases of anaphylaxis have been reported. Two reports describe anaphylaxis after administering multiple allergens at the same time. It is thought that the absorptive capacity of the membranes under the tongue may too limited to ensure proper exposure to multiple allergens administered together (New England Journal of Medicine, May 2008). It is for this reason that our office generally limits the number of allergens per bottle. Patients who have more than one vial of extract should separate administration by at least two hours. The third case of anaphylaxis was reported in a clinical trial determining whether SLIT could be helpful for latex allergy. In our office, latex allergy is determined by allergy skin tests and/or allergy blood tests. If allergic, avoiding latex products is the only treatment available at this time. Cost of sublingual immunotherapy. While the safety and effectiveness of allergy drops for immunotherapy has been proven in Europe, the FDA has yet to approve it in the United States. It is for this reason that sublingual immunotherapy is not currently covered or reimbursed by health insurance plans. The cost of treatment is $50 per vial, and vials should last at least one month. The total cost of treatment will depend upon the number of vials ordered. Patients are expected to pay for the allergy vaccine at the time of their office visit. Any extract mailed to the patient will have to be paid before shipping. We will continue to participate with your insurance company, as we currently do, for office visits, allergy testing, breathing tests and allergy injections administered in our office or at your primary care doctor's office. What if I am already receiving treatment at another doctor's office? You can continue any or all of your treatment at your current doctor's office. You will need to transfer your medical records, including your allergy skin test results, and if applicable, your current allergy extract. We will review your history and your records, and help you decide whether you would benefit from sublingual immunotherapy.
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Michigan Allergy, Sinus & Asthma Specialists
Web: www.michiganallergy.com Web: www.michiganfoodallergy.net Email: miallergy@comcast.net Please do not email confidential medical information.
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