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SLIT
FAQs

Frequently Asked Questions About Food Sublingual Immunotherapy

What is sublingual immunotherapy?

Sublingual immunotherapy (SLIT) is a form of immunotherapy that involves putting a liquid form of the food you are allergic to under the tongue. This has also been referred to as “allergy drops,” and it is an alternative treatment to oral immunotherapy (OIT). SLIT is delivered under the tongue, held there for two minutes, and then swallowed. SLIT has been used in patients with airborne allergies (hay fever and asthma) for many years in Europe, and has recently gained more interest in the United States. A few SLIT environmental allergens (dust mites, grass, and ragweed) have been approved by the US Food and Drug Administration (FDA), but none for food allergy.

How does SLIT work?

Food proteins placed under the tongue come in contact with oral mucus membranes and are then recognized by special immune cells called dendritic cells. These cells communicate with other immune cells (T lymphocytes) to hyposensitize you, or reduce your allergies.

What kind of allergies can be treated with SLIT?

The same kind of food allergies we’ve been treating with OIT, i.e. peanut, tree nuts, egg, milk, wheat and sesame.

Who could (or should) receive SLIT?

At the present time, food OIT is a popular method of treatment, but the ease and safety of SLIT makes it an attractive alternative, especially in the highly allergic person, children over 5 years old, or someone who has struggled with OIT.

Is SLIT safe?

Over the past 20 years, the safety of SLIT has been well documented. Fatal reactions to SLIT have not been reported to date, and serious reactions are extremely rare. Mild side effects, such as an itchy mouth, occur in the majority of people initially and tend to resolve over time.

Moderate side effects have been documented (1 in about every 12,000 doses), including: eye itching, nausea, vomiting, diarrhea, asthma symptoms and hives.
The strong safety profile of SLIT is largely due to the nature of the oral mucosa being conditioned to tolerate various proteins on a daily basis, such as foods and resident bacteria. As a result, the sublingual mucosa has few pro-inflammatory cells, such as mast cells (which trigger allergic reactions in the skin, nose and lungs). This helps to explain why SLIT, when compared to OIT, is less likely to cause a severe, generalized allergic reaction.

What are the advantages of SLIT compared to OIT?

SLIT has been shown to produce fewer adverse reactions than OIT. The early phase buildup drops have a sweet taste since the food is diluted in glycerin. Some patients have taste aversion with OIT since they are consuming the very food that not only caused a reaction in the past, but also the one they have been told and conditioned to avoid for many years. This can become a difficult psychological hurdle for some people. Placing < 1/10th of a teaspoon under the tongue rarely creates such anxiety.

What are the disadvantages of SLIT compared to OIT?

SLIT will make you safe from accidental exposure to the food you’re allergic to, but often does not allow free-eating of the food. SLIT patients are asked to return to the clinic annually for the first several years for an oral food challenge to measure how much of the food they can tolerate. At any of those time points, the patient is welcome to switch over to the safely consumed dose of food orally for ongoing treatment. Patients on staple food SLIT, egg, milk and wheat, often make that choice so they can incorporate these common foods into their diet.

Why is SLIT not yet FDA approved?

The drops are a food, not a drug, so approval is only necessary if a company wanted to market a specific, proprietary product. A trial is being done with a peanut product under the tongue and a food-based toothpaste. There is a peanut capsule approved by the FDA for OIT and work is being done with foods delivered via a skin patch (epicutaneous immunotherapy or EPIT).

How is SLIT taken?

Liquid food is self-administered at home, under the tongue. The early doses of the food are prepared here in the office and given to you from a bottle. You will use a small syringe to draw up a very small amount (less than 1/10th of a tsp) and squirt it under the tongue. The liquid is held under the tongue for approximately one minute before being swallowed. If you are on more than one food, the 2nd food can be taken one minute after the 1st. We ask that you don’t eat or drink for five minutes after dosing. You will receive a series of 2-3 low doses on the updose visits and instructed to stay on the top dose at home once daily. There will be four updose visits until you reach your maintenance dose. Foods are preserved in glycerin, keeping them stable for six months.

How long do I have to restrict activity before or after taking a SLIT dose?

None at all. Unlike OIT, there is no rest period before or after dosing with SLIT. We tested a dozen patients on an exercise bike with dosing immediately after exercise, followed by more exercise post-dose: they all did great! This wasn’t intense exercise, so a serious work out should probably be put off for 30 minutes after dosing.

Does SLIT need to be refrigerated?

The foods we provide you in solution can be left out of the refrigerator for weeks, if need be, but refrigeration is always best.

Can I travel with SLIT?

Yes. They are very easy to travel with and can go anywhere you go. The bottles have a small enough volume to be carried through airport security. Since taking the dose requires only a few minutes out of your day, it is very easy to continue your treatment no matter where you are, or how long you are away.

Does my insurance cover SLIT?

SLIT is considered a non-covered medical service, so there is an upfront program fee that will be out of pocket. Food challenges are a covered service, so the series of doses you will receive in the clinic will be billed to your insurance as such. There will also be a fee for refill bottles. The front office can review all charges with you prior to starting SLIT.

Are there options for patients outside of Florida?

Yes. Please contact us to explore creative options utilizing telehealth and remote monitoring to save you the high costs of travel and hotel stays. We do highly recommend Sarasota as a tourist destination, but do not want the expense to be a limiting factor in managing your severe food allergy.