What Is Sublingual Immunotherapy for Allergies?


What is immunotherapy?

Immunotherapy treats various conditions by introducing certain substances that activate or suppress the immune system. In the case of allergy immunotherapy, the immune system is retrained to develop an immunity or tolerance to harmless allergens instead of responding with an allergic reaction.

It almost sounds like magic: you take a few drops and like magic your allergies go away? It’s not that simple. In fact, it involves immune tolerance, antibodies, and a lot of science. We know allergy drops work the same way we know anything in science and medicine works -- we run experiments and clinical trials, and over time we begin to learn new information.

For over 30 years, scientists and doctors across the world have run clinical studies on allergy drops, also known as sublingual immunotherapy. Multiple studies have proven it to be both safe and effective. Furthermore, early treatment in young children with allergy drops appears to decrease their risk of asthma later in life.

Allergy drops have been supported by the American Academy of Otolaryngologic Allergy, the American Academy of Allergy, Asthma and Immunology, and some forms of sublingual immunotherapy have been approved by the FDA. That’s a lot of support.

As physicians at Wyndly Health, we’ve also taken care of and cured thousands of patients in our own allergy practice using allergy drops. Over our years of clinical experience, we’ve seen our patients improve, and we’ve seen similar results to those in the scientific studies. In short, allergy drops work.

In fact, that’s why we started Wyndly Health. We wanted to take this safe and effective treatment and make it accessible to patients regardless of where they live and in the most convenient way possible.

How Many People Actually Have Allergies?

 About 20-25% of the population suffers from some type of allergy. Examples of allergies are food allergies, asthma (related to allergies), itchy skin (known as dermatitis), and hives (known as urticaria). Allergies are the 5th most common chronic disease when you consider everyone, and it is the 3rd most common disease in children. To make matters worse, from the available research, allergies seem to be increasing.

Who Is a Good Candidate for Immunotherapy or Allergy Drops?

Immunotherapy, or allergy drops, is a good solution for a few types of people:

  • Someone who is allergic to multiple things
  • Someone who can’t control their symptoms with medications
  • Anyone who has had a bad reaction to an allergy medication
  • Children whose parents are hoping to try and prevent them from getting asthma later in life
  • Anyone who doesn’t want to be stuck on allergy medication forever
  • Someone who has both allergies and asthma and wants to treat them 

What Is the History of Allergy Drops?

The first report of oral immunotherapy was in 1900, when H.H. Curtis used whole weed extract to treat hay favor. But allergy drops grew in popularity in 1986 when doctors began looking for an alternative to allergy injection shots after 26 people died of allergy shots in England. The British Committee own Safety of Medicines started looking for an alternative method to allergy injection shots, and that is when people began really looking into allergy drops as a safer and effective treatment for allergies. In 1998 the World Health organization published literature supporting allergy drops.

Are They Safe?

There have been numerous studies on the safety of allergy drops, otherwise known as sublingual immunotherapy. The AAAAI/ACAAI Sublingual Immunotherapy (SLIT) task force report looked at 66 studies, or over 1 million doses of allergy drops and found that there were no fatal side effects. There were reactions in 0.056% of doses, with most of the side effects being oral itching, runny nose, nausea and rarely abdominal pain; but remember this is in less than 1% of 1 million doses. In 2012, another review found that the risk of a bad allergy reaction in sublingual immunotherapy was approximately 1 bad reaction per 100 million doses. Overall, the data supports that allergy drops are very safe.

How Do We Know They Work?

It’s time to nerd out. Let’s go over the actual clinical studies and what the findings mean. For each study, we’ll go over our interpretation of the results (which we feel confident of because we’re doctors who spent 10 years studying this stuff) but we will link the papers so you can review them yourself. We love when patients do their own research, and we want to make it easy for you to do it.

The first randomized trials on allergy drops began in 1986 by Scadding and Brostoff. The first large scale US sublingual immunotherapy trial was done in 2011 which led to the FDA approving methods of sublingual immunotherapy in the spring of 2014. Over the year, numerous studies have shown allergy drops to decrease patients allergy symptoms, decrease their need for allergy medications, and decrease development of new allergies.

A few good studies to review are this Cochrane review (which is a review study of a number of different studies) and this Meta-analysis (where they also analyzed the results of multiple studies). Morogna in 2010 released data from following patients for 15 years after allergy drops where the benefits of allergy drops continued.

Another meta-analysis also showed allergy drops were better then antihistamines and montelukast for allergy treatment. In children, this meta-analysis even showed that allergy drops seem to prevent new allergies from being formed. Another similar study can be found here.

In general, all of the studies show a decrease in symptoms and need for medications with some evidence that it prevents new allergies, and some evidence that it can decrease asthma development in children.

What Is the Difference Between Shots and Drops?

Both allergy drops and allergy shots work by changing the way your immune system works. The difference is in the way in which we expose your body to things you are allergic to.

For allergy shots, the way we expose your body to things you are allergic to is by using needles to inject these things into your skin to allow your immune system to react. For allergy drops, the way we do this is through exposure under your tongue. 

Allergy shots work well, but require frequent visits to a doctors office for the shots. Also, the shots sometimes hurt, and there is a risk of a life-threatening reaction called ‘anaphylaxis.’ Allergy drops, on the other hand, can be taken from home, do not require any injections, and have a much smaller risk of anaphylaxis. This is why many patients elect to use allergy drops instead.

There have only been a few head to head comparison studies between the two, but in nearly all the studies, both allergy shots and drops have been shown to be effective in reducing symptoms and the need for medication in allergy patients.

The other method of immunotherapy is sublingual immunotherapy via allergy pills. There are a few FDA approved allergy immunotherapy pills, however, these only work for a specific allergy like ragweed or dust mites. These are good for patients that only have one main allergy.

Ultimately, we recommend patients choose the therapy that is best suited for their life.

Understanding Allergic Reactions

When your body is exposed to something that is not supposed to be there, like a virus, or something that causes an allergy like pet dander, your body sticks an antibody on it. This antibody essentially acts as a label. This antibody label tells other cells in your body to react in a certain way. For allergies, this antibody label tells your body to release a molecule called histamine. The release of histamine is what causes you to have itchiness, swelling, sneezing, and allergy symptoms. This is why we use antihistamines to treat allergies. Some examples of antihistamines are Benadryl, Claritin, Zyrtec, or Allegra.

How They Work

Allergy drops work by changing the way your body’s immune system reacts. Most of the time, your body labels something you are allergic to with an antibody that causes histamine to be released. Allergy drops work by decreasing the number of antibodies that release histamine that you have, and instead creating more antibodies that do not cause allergy symptoms. Over time, this makes you tolerant to your allergies and leads to relief of your symptoms.

Learn More With Wyndly

At Wyndly, we believe allergy care deserves undivided attention and modern treatments. We use sublingual immunotherapy to train your body to ignore its allergy triggers. Interested? Start with an allergy test to see if you’re a fit.

originally published September 13, 2020

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