In many cases, the answer is “yes, typically for a number of years.” The right way to think about this topic is to remember that having an allergic condition or being prone to allergies is really a chronic medical condition, and chronic medical conditions typically require management of some form for a person’s entire life, usually by a combination of dietary, lifestyle, and medical management. Immunotherapy such as SLIT can be a great tool to add to these other methods in order to help control your chronic allergy condition(s), and it may even get you to the point where your control is maintained off of active treatment for some time.
Studies have shown that after 3-5 years of treatment with sublingual immunotherapy for environmental allergies, many people are able to stop their SLIT treatment (if desired) and maintain their results of improved symptom relief and allergen tolerance while off treatment for at least 1-2 years. This is called having a period of “sustained tolerance” due to the long-term effects of your SLIT treatment. A prolonged rather than rushed course on immunotherapy has been shown to be important to achieving this type of result, with some studies suggesting that immunotherapy treatment for 4-5+ years can lead to longer persistent results off of treatment later than immunotherapy done for 3 or less years. This is similar to the findings about the length of time some people experience persistent results after the standard 3-5 years of allergy shots (SCIT).
In our clinical experience, as well as in discussing with patients who had been on SLIT decades ago and allergists who have been providing SLIT for a long time, it appears that many people who have been on a long-term course of SLIT do have sustained benefit off of treatment for years and sometimes decades. So many factors play a role in exactly how this result may be for you, including factors that occur while you are off of your SLIT treatment, so there is no exact way to predict a length of sustained benefit ahead of time.
Restarting another course of SLIT treatment if needed down the road, due to a change in environment or return of symptoms, can often bring your immune system and allergy symptoms back under good control even more quickly than the first time. It can then again potentially provide you with even more years of sustained tolerance when cycled off of the treatment again (if desired). For those who notice benefit on their SLIT treatment but do not have a sustained tolerance period after stopping the treatment (due to other immune-related or environmental factors that cannot be changed), there is always the option of safely remaining on the treatment indefinitely.
Less has been formally studied about food allergy SLIT, but it makes sense that there would be some similarities to the results of environmental allergy SLIT discussed above in regards to the re-training of the immune system and possible sustained tolerance off of treatment. However, it also makes sense that there could be some differences, especially depending on the molecular properties of your specific food allergens, as well as based on other factors including your ingestion patterns. At Allergenuity Health, Dr. Schroeder will discuss with you the likely scenarios for you specifically, based on your personal allergy history and allergen details, and how your immune system appears to be handling your food SLIT treatment along the way.