Sublingual Immunotherapy (SLIT)

What is Sublingual Immunotherapy?

Sublingual immunotherapy (SLIT) is the use of allergy drops placed under the tongue to treat the cause of your allergies. After obtaining acareful medical history and appropriate allergy test results, our staff follows a well-researched approach, to create an allergy vaccine that contains the specific allergens that you are allergic to. These allergens, when placed under the tongue, interact with special immune cells, and with repeated administration of these drops, your immune system becomes less allergic.

Sublingual immunotherapy (SLIT) is very similar to allergy injection therapy (AIT), in that both treatments modify the primary abnormality in allergicdisease -- the immune system's over-reactivity to allergens such as pollen, dust mite, animal dander, food, etc. Both SLIT and AIT treat this immune abnormality (this hyper-responsiveness to allergens), whether the allergic reaction occurs in the nose, sinuses, lungs, skin or GI tract.

What are the advantages of SLIT versus allergy injection therapy?

Although sublingual immunotherapy is not considered more effective that allergy injection therapy, there are several clinical situations when SLIT maybe a reasonable alternative.

Because SLIT is much less likely to cause adverse reactions, it can be self-administered at home. The patient no longer has to drive to the doctor's office every week to get a shot and wait 20-30 minutes.
For patients who suffer from hay fever only in the Spring or late Summer, starting SLIT therapy 6-8 weeks before the pollen season may allow for rapid desensitization to tree, grass, ragweed or weed pollen, without having to take allergy shots for theentire year. In Michigan, we recommend starting allergy drops for tree pollen sensitive patients around March 1st; for grass pollen allergic individuals around May 1^st; and for ragweed pollen sensitive patients around August1^st.
For patients already on allergy injection therapy, SLIT can be used as an add-on treatment, especially during high pollen seasons, when allergy shots alone are not providing satisfactory symptom relief.
SLIT therapy can be given to highly allergic infants and young children not old enough for allergy shots.
SLIT therapy has been used for patients with moderate or severe asthma who are not considered good candidates for allergy shots.
For patients with eczema that is flared by food allergy, SLIT therapy, along with avoidance of the food(s), can be quite helpful. SLIT therapy may help control against flare-ups when accidental ingestion of offending food(s) occur.
Allergy patients frequently have several colds, sinus infections, ear infections (especially young children) and bronchitis throughout the year, and are therefore often sick and not well enough to receive allergy shots on a regular basis. Because SLIT therapy rarely causes reactions, it can be administered to patients with chronic sinusitis, chronic otitis media and chronic asthmatic bronchitis. Once patients have stabilized with SLIT, they can continue with allergy drops or switch over to allergy injections.
Patients with a real fear of needles can alternatively choose SLIT for allergic desensitization.
Patients who travel frequently for work or on vacation, SLIT allows the patient to continue allergic desensitization,without having to find a new doctor's office.

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?

Allergy vaccine drops, when placed under the tongue on the oral mucus membranes, interact with special immune cells called dendrites, which then interact with other immune cells (T lymphocytes) to decrease the person's hyperactive allergic sensitivities (causing an 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.

Sublingual Allergy Drop Center Protocol

Sublingual immunotherapy, as practiced at the Sublingual Allergy Drop Center at Michigan Allergy, Sinus & Asthma Specialists, is based on the scientific and clinical literature, and we follow the most current, evidence-based research available. We listen carefully to each patient's history, and your SLIT vaccine is coordinated with carefully done allergy skin test and/or appropriate blood (RAST) test results.

As SLIT therapy continues to gain momentum around the USA, it is important to note that not all of the methods of SLIT are following the same protocol nor having the same results.

According to our protocol, SLIT dosing is determined by both the patient's history and their allergy skin test results. We do not make any allergy vaccine based only on skin or blood test results. Moreover, the doctor not only takes your history, but also reads your skin test results. We do not use nurse practitioners or physician assistants, and we make each vial of allergy vaccine on site in our office under carefully supervised conditions.

Your allergy drop vaccine is customized exactly to your needs. We also believe it is best to address all of your allergies comprehensively.

More than 90% of our patient population has multiple allergy problems. By mixing allergens in 50% glycerin, an extremely effective preservative, we are able to treat multiple allergies at the same time without other allergens degrading or interacting with one another.

We have also found, as is true from the scientific and clinical evidence, that the patient needs to take multiple doses on a daily basis. Multiple dosing is necessary in order to maintain constant, uninterrupted allergen desensitization. Studies have indicated that persistence of allergen on the oral mucus membranes may be the most effective method of inducing desensitization.

Published articles showing the effectiveness of SLIT

SLIT has been in practice for almost forty years, primarily in Europe. Between 1990 and 2005, more than 40 controlled trials with sublingual immunotherapy 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 these several controlled studies, concluded that SLIT could be a reasonable 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).

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, infrequent side effects included itching of the ear lobes and throat. If bothersome, these side effects were easily managed with oral antihistamines.

In more than 40 years of clinical experience with sublingual immunotherapy, involving millions of doses of SLIT, a severe allergic reaction (anaphylaxis) to SLIT has rarely been reported. In a May 2008 issue of the New England Journal of Medicine, in reviewing the efficacy and potential side effects from SLIT, only two cases of anaphylaxis were noted.

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 SLIT treatment in the United States is considered "off-label" and why SLIT is not currently covered or reimbursed by health insurance plans. 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.

What are the advantages of Allergy Injection Therapy versus SLIT?

Allergy injection therapy is covered by most insurance plans. Because SLIT has not been approved by the FDA, it must be prescribed "off label," making it highly unlikely that any insurance company will reimburse you for the allergy vaccine. This would not apply to any patient whose health insurance has no or very limited allergy benefits.
Our office protocol suggests weekly allergy shots for 20-24 injections, to reach a maintenance dose. Shots are then given every two weeks (twice a month) for the next 6 months. After the first year, most of our patients are able to take their allergy shots every 3-4 weeks for the next two years.
For SLIT to be most effective, patients need to take their allergy drops, usually two or three times a day, every day.

Although SLIT can be given on a year-round basis for multiple allergens, the Sublingual Allergy Drop Center believes that SLIT is most beneficial and cost-effective when given to:

prevent seasonal flare-ups (Spring and/or Fall)
as an add-on treatment for allergy shot patients during allergy flare-ups
for infants and young children not old enough for shots
moderate or severe asthmatics not considered good candidates for allergy shots
for patients with eczema flare by food allergy
patients with recurrent sinus and ear infections
patients with a real fear of needles.
patients who do not have the time to drive to a doctor's office for allergy injections
patients who travel frequently for work or for vacation

Please feel free to contact our office if you have further questions regarding SLIT therapy.