Sublingual Immunotherapy (SLIT)
Sublingual immunotherapy (SLIT) involves providing small doses of what a person is allergic to
in an attempt to increase tolerance to the allergen. Small doses of the allergen are given under the
tongue.
The dosage gradually is increased during the first several months, which is known as the
“escalation phase.” The “maintenance phase” consists of using the same dose of drops each day.
Most people will need to use the drops for 3–5 years. Most people give themselves the drops three
times a day. Physicians generally retest allergies and adjust dosage every 3–6 months.
Note: This handout refers to allergy drops, but some physicians may use tablets that are dissolved
under the tongue.
Is this safe?
The antigen used in allergy drops is the same as that used in traditional allergy injections. It is
very safe if done correctly. The World Health Organization (WHO) has endorsed sublingual
immunotherapy as a viable alternative to injection immunotherapy, which involves going to the
doctor’s office for a shot every week. WHO states, “The safety of SLIT is superior to that of
subcutaneous immunotherapy (SCIT), and no fatality has been reported in 23 years of trials and
clinical use. The most frequently reported events were irritation of the throat and oral itching.
According to the recent data, the number of side effects seems to be dose-dependent, as happens
with SCIT.”
For more than 40 years, no single systemic, anaphylactic, or near fatal reaction has occurred from
use of the La Crosse Method™. The La Crosse Method involves calculating each individual’s
dosage based on allergy testing results. Adjustments to the dosage are based on allergy retesting,
and the dose is increased as the patient’s tolerance increases. Treatment methods other than the La
Crosse Method have resulted in a few serious reactions and an increased frequency of side effects.
Physicians may suggest environmental changes or symptom-relieving medication as needed
during treatment. Between 50% and 75% of allergy sufferers in southern Europe use allergy
drops.
The American Academy of Allergy, Asthma, and Immunology (AAAAI) states that, “In one
review of the literature, the authors estimated that in approximately 1.2 million doses
administered to 4400 patients, there were no serious, ‘life-threatening reactions’. There are reports
of anaphylaxis with SLIT, but the incidence is rare. The primary symptoms reported by subjects
receiving SLIT included mild ‘local’ itching/burning of the mouth or lips, increase in rhinitis
symptoms, gastrointestinal symptoms, and rarely, an increase in asthma symptoms. The reactions
reported by subjects receiving SLIT were only significant enough to make the subject stop taking
SLIT in less than 5% of the cases. SLIT has been studied in children as young as a year old. The
primary symptoms reported by parents were oral itching, itchy skin, abdominal pain, and nausea
and vomiting.”
How effective is SLIT?
A recent Duke University study found that allergy drops safely induced desensitization in children
with peanut allergies and suggested a significant change in allergic response. Children treated
with the drops could ingest an average of six or seven peanuts before reacting, while the placebo
group had a reaction after consuming a part of one peanut. Peanuts were chosen for the study,
because it is the most serious and sensitive food allergy.
According to the AAAAI, “Some studies report that SLIT takes at least 2 years of treatment
before subjects see improvement in symptoms. Other studies show improvement within a single
year of therapy. One large review of over 100 SLIT research studies demonstrated that about one
third of studies showed significant improvement in symptoms while one third showed no
significant improvement. The variation in effectiveness had been attributed to the differences in
the dose of allergen used for the various studies. In general, the higher doses of allergen appeared
to have the largest impact on symptom improvement.”
Who is likely to benefit from SLIT?
Allergy drops are beneficial for children with eczema and recurrent ear infections, severe
asthmatics, patients with chronic sinusitis, patients with food and mold allergies, and patients with
multiple allergies.
Are allergy drops better than allergy injections?
AAAAI points out that, “Allergy shots involve frequent injections of increasing amounts of
allergen extract. They can be effective at controlling symptoms of allergic rhinitis, but the
injection schedule can be difficult to maintain, local reactions to the injections are common, and
severe allergic reactions and even deaths have been reported.”
What else do I need to know?
Most insurance plans do not cover SLIT. It is considered an “off label” use by the FDA. The cost
is estimated at approximately $1.50/day during the first year and then $1.00/day after that.
References and recommended readings
Allergychoices, Inc. Safety and effectiveness of allergy shots. Available at:
http://www.allergychoices.com/WhyAllergyDrops/AboutAllergyDrops/SafetyAndEffectiveness/.
Accessed May 31, 2011.
Allergychoices, Inc. Steps to allergy drop treatment. Available at:
http://www.allergychoices.com/WhyAllergyDrops/AboutAllergyDrops/StepsToTreatment/.
Accessed May 31, 2011.
Allergychoices, Inc. Who benefits from allergy drops? Available at:
http://www.allergychoices.com/WhyAllergyDrops/AboutAllergyDrops/WhoBenefits/default.aspx.
Accessed May 31, 2011.
American Academy of Allergy Asthma & Immunology. Sublingual immunotherapy (SLIT).
Available at:
http://www.aaaai.org/patients/treatments/sublingual_immunotherapy.stm. Accessed May 31,
2011.
Johns Hopkins Sinus Center. Sublingual immunotherapy. Available at:
http://www.hopkinsmedicine.org/sinus/allergy/sublingual_immunotherapy.html. Accessed May
31, 2011.
Rindfleisch T. Peanut allergy drops work: Duke study shows local clinic’s method effectively
curbs kids’ reactions. Available at: http://lacrossetribune.com/news/local/article_c0fb7ba2-4d2d-
11e0-9b2c-001cc4c03286.html. Accessed May 31, 2011.
WGNtv.com. Allergy drops. Available at: http://www.wgntv.com/news/medicalwatch/wgntv-
allergy-drops-june14,0,5683672.story. Accessed May 31, 2011.
Review Date 7/11
G-1696