Sublingual Immunotherapy (SLIT)
What is sublingual immunotherapy (allergy drops)?
Immunotherapy treats the root cause of allergies by giving you small doses of what
you are allergic to in order to increase your “immunity” or tolerance and reduce the
allergy symptoms. Unlike allergy shots (injection immunotherapy), sublingual
immunotherapy or SLIT is given as drops under the tongue. Unlike allergy medicines,
which only treat allergy symptoms, sublingual immunotherapy addresses the underlying
cause of allergies. The antigens used in allergy drops are the same used in allergy shots.
They are also prepared the same way as allergy shots. The difference is in the route of
administration - a dropper that delivers the antigen under the tongue versus a syringe
injecting the antigens into the skin.
How does the process work?
The first step is to confirm your allergies through allergy testing. A custom-mixed
vial of drops is then prepared. You place the drops under your tongue every day.
The number of drops is gradually increased during the first ten days, called the
“escalation phase.” After that, you take the same dose or number of drops each day.
The immune system of the gastrointestinal tract learns to "tolerate" the antigen or
foreign substances, meaning that it does not respond in an over-active way. When SLIT is
administered into the gastrointestinal tract, the immune system tolerates the allergen
instead of causing an over-reacting of the immune system, such as with an allergy
This results in less allergy symptoms when the body is exposed to the allergy source,
such as airborne pollen or pet dander.
Is sublingual immunotherapy safe?
Yes, it is very safe for both adults and children. The World Health Organization (WHO)
has endorsed sublingual immunotherapy as a viable alternative to injection immunotherapy. Over the past 10 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:
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lip, mouth and tongue irritation
eye itching, redness and swelling
nausea, vomiting, abdominal cramping and diarrhea
sneezing, nasal itching and congestion
asthma symptoms
hives, itching and swelling of the skin
Because SLIT is so safe people generally treat themselves at home and are followed
in the clinic at close intervals to monitor response to treatment.
Who can (or should) receive SLIT?
People with documented allergic disease by allergy testing and not controlled with allergy
medicine may benefit from SLIT, to include young children and adults. Just like allergy
shots, pregnant women should wait until after they deliver to start SLIT, but if a female
becomes pregnant while on SLIT she can continue therapy. People with severe
asthma need to be monitored more closely since SLIT can worsen asthma symptoms.
Why is SLIT not FDA-approved?
Currently, allergy extracts are approved by the FDA for use through injections but not
under the tongue. Therefore, allergy drops are considered an “off-label” use of the
FDA-approved allergy extracts. Physicians commonly prescribe “off-label” use for
many drugs, such as blood pressures medication for migraines, aspirin for heart
conditions, or arthritis drugs for the treatment of shingles. Using allergy extracts under
the tongue is both legal and very common. FDA approval for sublingual immunotherapy
is currently pending.
Does it work?
Yes. Many scientific studies have shown that SLIT significantly reduces allergy
symptoms.
How long must I continue the treatment?
We recommend you use the drops for at least 3 years so that the body will build up a
lasting “immunity.”
What are the costs? Will it be covered by insurance?
Allergy testing and injection immunotherapy are covered by insurance, but since SLIT
is an “off-label” use of allergy extracts it is not covered by most insurance plans. However,
when compared with the cost of allergy shots, SLIT may be a more economical choice
depending on your insurance and situation. Since SLIT is administered at home there
are very few office visits and therefore you save time, the cost of driving, and your
weekly out-of-pocket cost until your deductible is met. The cost is of SLIT is
approximately $1.00 per day which is comparable to over-the-counter allergy
medicines such as Claritin or Zyrtec that treat allergy symptoms. Our front office
personnel can help you determine the most cost-efficient treatment.