Allergies are an unfortunate part of life that many people learn to suffer through. Whether it’s seasonal grass or ragweed, ever-persistent indoor dust mite issues, or dreaded side effects from a visit to a dog or cat lover’s home, chronic allergies negatively affect the lives of up to 30% of adults in the US (1).
What causes allergies?
When the immune system reacts to a substance and recognizes it as foreign, it will produce many white blood cells to attack this foreign antigen. White blood cells release chemicals as a part of their attacking response, the most common being histamine. These chemicals dilate blood vessels, producing symptoms like a runny nose, sneezing, and itching, watery eyes (2). This immune response is known as allergic rhinitis, or hay fever. Rhinitis can be either seasonal or perennial, depending on when symptoms seem to spike. Those with seasonal allergic rhinitis find themselves reacting most strongly in spring, summer, and fall against the higher levels of airborne mold spores or tree, grass, or weed pollen. Perennial allergic rhinitis, on the other hand, usually occurs in reaction to year-round indoor antigens, such as dust mites, cockroaches, certain types of mold, and pet hair or dander (3).
Treatments for Allergies
The most common treatments for rhinitis largely involve managing symptoms. We’ve all heard of antihistamines, which are available over-the-counter and work to directly mitigate the effects of the immune response of histamines discussed above. Intranasal corticosteroids, nasal sprays, decongestants, and other drugs all work to reduce symptoms, as well. Other suggestions for managing rhinitis involve taking measures to simply avoid allergens, such as keeping windows shut during high-pollen seasons, avoiding contact with animals or homes that have animals, or investing in dust mite-proof mattress covers (3).
Unfortunately, none of these treatments create long-term tolerance for the allergens, so they must be used each time an allergen presents itself and symptoms arise. While taking medication to curb symptoms every day may be sufficient for some, for those that find the treatment listed above aren’t sufficient, do not like the side effects of allergy medications, or are seeking long-term relief, there is an alternative option that many have turned to, allergy immunotherapy.
Immunotherapy is the process of exposing the immune system to increasingly large amounts of allergens, resulting in increased tolerance to the allergens and a decrease in rhinitis symptoms over time. In other words, white blood cells build up a tolerance, so it begins to take a lot more of the allergen to get them to produce the same levels of the symptom-producing chemicals mentioned above (4). It is unique in that it is the only type of treatment that can cause long-term improvement of symptoms, even after treatment ends (5, 12). In the United States, subcutaneous (under the skin) immunotherapy has been the standard for allergy therapy, which involves receiving shots from a healthcare professional two or more times a week. However, sublingual (under the tongue) immunotherapy is seeing a rise in popularity, which can deliver the same results but through safer, far more convenient means (9).
Subcutaneous vs Sublingual Immunotherapy
Both types of immunotherapy begin by talking to an allergist about your health history, as well as completing either a skin- or blood-based allergy test (6). These will determine the severity and types of your allergies. Based on your results, your allergist will prescribe specific doses of allergens within your allergy shots or allergy drops/tablets.
Both types of immunotherapy have three stages of treatment, and both require anywhere from 2-5 years to provide long-term results (5). The first stage involves creating an initial tolerance. The immune system will slowly adjust to receiving the treatment, and any overt reactions to the immunotherapy, like itching at the site of treatment, will diminish during this time. Some patients even find that their general allergy symptoms may begin to decrease as well (12). This usually takes about 1-3 months.
The second stage takes more time, anywhere from 3 months to 2 years. Allergen tolerance in the body is actively increasing during this time, and most people find that their symptoms are greatly decreased, if not eliminated fully (7).
Stage three can be considered the most crucial stage for long-term results. By continuing allergen exposure to the body even after symptoms become more manageable, the imm