From the Guidelines
People see benefits from allergy shots (immunotherapy) through gradual reduction in allergy symptoms and decreased need for medications, as supported by the most recent clinical practice guideline published in 2024 1. Allergy shots work by exposing the body to small, increasing amounts of allergens over time, typically starting with injections 1-2 times weekly during a 3-6 month build-up phase, followed by maintenance injections every 2-4 weeks for 3-5 years. Benefits include decreased sensitivity to allergens like pollen, dust mites, pet dander, and insect venom, with many patients experiencing significant improvement within the first year. The treatment works by helping the immune system develop tolerance to allergens, shifting from an allergic response to a non-allergic one by producing blocking antibodies that prevent allergens from triggering symptoms. Some key points to consider when evaluating the benefits of allergy shots include:
- The treatment is effective for both adults and children, as confirmed by multiple studies, including a practice parameter update from 2008 1.
- Allergen immunotherapy may prevent the development of new allergen sensitizations and reduce the risk for the future development of asthma in patients with allergic rhinitis, as noted in the 2008 practice parameter update 1.
- The estimated allergen immunotherapy fatality rate is very low, at 1 per 2.5 million injections, according to a survey of physician members 1.
- Clinicians should offer or refer to a clinician who can offer immunotherapy for patients with allergic rhinitis who have inadequate response to symptoms with pharmacologic therapy, as recommended in the 2015 clinical practice guideline executive summary 1. Side effects are usually mild, including redness or swelling at the injection site, though rarely more serious reactions can occur. Patients should commit to the full treatment course for maximum benefit, as stopping too early may result in symptoms returning. Unlike medications that only mask symptoms, immunotherapy addresses the underlying cause of allergies and can provide long-lasting relief even after treatment ends. It's worth noting that both subcutaneous immunotherapy (SCIT) and sublingual immunotherapy (SLIT) are considered safe and effective, but patients should discuss the available options with their healthcare provider to determine the best course of treatment, as recommended in the 2024 clinical practice guideline 1.
From the Research
Benefits of Allergy Shots
- Allergen immunotherapy (AIT) is an effective treatment for allergic rhinitis, inducing long-term clinical tolerance to the sensitizing allergen 2
- AIT is associated with the modulation of innate and adaptive immune systems, including inhibition of IgE-dependent activation of mast cells and basophils, suppression of TH2 cells, and induction of T and B regulatory cells 2
- Subcutaneous allergen immunotherapy (SCIT) is a proven treatment of allergic rhinitis, asthma, atopic dermatitis, and prevention of Hymenoptera venom anaphylaxis 3
- Allergy immunotherapy is the only proved disease modification therapy associated with lasting benefits after discontinuation 4
Reduction of Symptoms
- AIT can reduce symptoms of allergic rhinitis and asthma by inducing immune tolerance 2
- SCIT can prevent Hymenoptera venom anaphylaxis and reduce the risk of systemic allergic reactions 3
- AIT can also reduce the risk of anaphylaxis and improve quality of life for patients with allergic diseases 4
Long-term Effects
- Clinical tolerance induction can be achieved when AIT is administered for at least 3 years 2
- AIT can provide lasting benefits after discontinuation, making it a valuable treatment option for patients with allergic diseases 4
- The long-term effects of AIT can include reduced symptoms, improved quality of life, and decreased risk of anaphylaxis 2, 4