Allergy shots, also known as allergen immunotherapy, represent a long-term treatment approach designed to alleviate symptoms for individuals with certain allergies. This therapeutic method involves regularly administering small, controlled amounts of substances that trigger allergic reactions in a person.
How Allergy Shots Work
Allergy shots function by systematically exposing the immune system to increasing doses of specific allergens. When an allergen enters the body of an allergic individual, the immune system typically overreacts by producing immunoglobulin E (IgE) antibodies, which trigger allergic symptoms like sneezing or itching. The goal of immunotherapy is to shift this immune response.
Through repeated exposure, the body is encouraged to produce a different type of antibody, immunoglobulin G (IgG), particularly IgG4. This IgG acts as a “blocking antibody,” intercepting allergens before they can bind to IgE and trigger an allergic cascade. This process helps the immune system build tolerance, reducing its sensitivity and leading to fewer or less severe allergic reactions.
Who Is a Candidate
Allergy shots are for individuals with persistent allergy symptoms that are not adequately managed by other treatments like medications or environmental controls. They are typically effective for allergies to airborne substances like pollen, dust mites, mold spores, and pet dander. It is also a well-established treatment for severe reactions to stinging insects, including bees, wasps, and hornets.
While generally suitable for both children and adults, immunotherapy is usually not recommended for children under five years old, primarily due to potential difficulties in their ability to communicate any side effects. Considerations for candidacy also include the severity of symptoms, the duration of allergy seasons, and a person’s willingness to commit to the treatment schedule. Allergy shots are not used for treating food allergies.
The Treatment Process
Allergy shot treatment involves two phases: the build-up phase and the maintenance phase. The build-up phase begins with low doses of allergen extracts, administered frequently, typically one to three times per week. The amount of allergen in each injection is gradually increased to help the body develop tolerance.
This phase usually spans six to ten months, though it can range from three to twelve months depending on the individual’s response and the frequency of injections. Once the maximum tolerated dose, known as the maintenance dose, is reached, the patient transitions to the maintenance phase. During this phase, injections are given less frequently, generally once every two to four weeks, and this phase typically continues for three to five years to achieve lasting effects. Patients are commonly asked to remain in the clinic for at least 30 minutes after each shot to monitor for any immediate reactions.
Outcomes and Practical Considerations
Allergy shots can significantly reduce allergy symptoms and decrease reliance on medications. Most people notice symptom improvement within six to twelve months, with the most significant changes often observed during the second year. Approximately 80% to 90% of individuals show improvement, and about 60% may experience lasting benefits even after treatment concludes after three to five years.
While generally well-tolerated, responses to allergy shots can occur. Local reactions, such as redness, swelling, or itching at the injection site, are common and usually resolve within hours. Less common are systemic reactions, which may involve symptoms like sneezing, nasal congestion, hives, or chest tightness, but these are typically mild. A severe, life-threatening reaction called anaphylaxis is rare but possible, often occurring within 30 minutes of the shot, which is why post-injection observation is standard. The financial aspect varies; most insurance plans cover the cost of allergy shots, although out-of-pocket expenses may depend on specific coverage. The treatment also requires a substantial time commitment due to regular clinic visits over several years.