How Long Do You Get Allergy Shots? The Exit Strategy Explained

The primary indicators that your allergist will evaluate before recommending discontinuation include sustained symptom improvement through at least 1 to 2 full allergen seasons on maintenance, substantial reduction or elimination of your daily rescue medication use (antihistamines, nasal steroids), and at least 3 years of completed maintenance dosing. Secondary indicators may include reduced skin test reactivity, decreased allergen-specific IgE, and improved allergen-specific IgG4-to-IgE ratio — biomarkers associated with successful immune tolerance per Shamji and Durham in JACI 2017. The decision is individualized: your allergist weighs these factors alongside your treatment history, allergen type, and personal goals.

After stopping allergy shots, the disease-modifying immune changes — regulatory T-cell tolerance, IgG4 blocking antibodies, reduced mast cell and basophil sensitivity — continue producing benefit without further injections. Durham et al. in NEJM 1999 established that grass SCIT benefit persisted at least 3 years post-discontinuation. Eng et al. in Allergy 2006 documented 12-year sustained benefit in a long-term cohort. However, 10 to 25 percent of patients experience meaningful symptom recurrence within 3 years of stopping. Post-treatment monitoring — annual allergist visits for 2 to 3 years — allows early detection of recurrence before symptoms become disabling again. Skin test reactivity may gradually return even as clinical remission persists.

Symptom improvement alone is not sufficient reason to stop allergy shots before completing the recommended minimum of 3 years of maintenance. Many patients experience significant symptom reduction early in maintenance — sometimes even during build-up — but stopping before completing the recommended course dramatically increases the risk of relapse. Nouri-Aria et al. in JACI 2004 demonstrated that patients who stopped before 3 years had significantly higher relapse rates than those who completed the full course. The EAACI guidelines by Roberts et al. in Allergy 2018 explicitly state that 2-year courses are insufficient for sustained post-treatment benefit. Discuss any desire to stop early with your allergist before making changes to your treatment schedule.

If allergy symptoms recur after stopping allergy shots — which happens in 10 to 25 percent of patients within 3 years of stopping — retreatment is an effective option. Patients who have completed a prior SCIT course and relapsed may benefit from a shorter build-up period on retreatment, though this depends on the time elapsed since the previous course and the degree of immune tolerance remaining. Per Cox et al. in JACI 2011, retreatment is generally effective and the allergist will assess whether a full restart or accelerated build-up is appropriate. Some patients also extend their original course before discontinuation if early-relapse risk factors are present. Early relapse is more common in patients who stopped before completing 3 full years.

For the vast majority of patients with inhalant allergen allergies — pollen, dust mites, pet dander, mold — allergy shots are a finite 3-to-5-year course with a defined endpoint, not a lifelong commitment. The notable exception is venom immunotherapy for patients with severe systemic reactions to Hymenoptera stings. Golden et al. in JACI 2011 established that patients with severe initial reactions, systemic mastocytosis, elevated baseline tryptase, or honeybee allergy face a residual systemic-reaction risk of 5 to 15 percent even after 5 years of venom IT — making indefinite treatment the recommended approach for this high-risk subgroup. For inhalant allergen SCIT, the answer is no — treatment has a defined endpoint.

Evidence suggests that 5-year courses may provide more durable post-treatment benefit than 3-year courses, though no head-to-head randomized trial has directly compared the two durations with the same protocol. Eng et al. in Allergy 2006 reported 12-year sustained benefit in a childhood grass SCIT cohort that received a longer preseasonal course — longer than the 3-year Durham et al. protocol. Shamji and Durham in JACI 2017 reported that longer treatment is associated with more sustained IgG4 blocking antibody levels and deeper regulatory T-cell programming. The AAAAI recommends a minimum of 3 years but defers to allergist judgment on extending to 5 years based on polysensitization, asthma comorbidity, and persistent symptoms at the 3-year mark.

No single biomarker reliably predicts optimal SCIT stopping time, and the AAAAI practice parameters do not endorse routine biomarker testing as the primary discontinuation criterion. However, several biomarkers associated with successful immune tolerance may inform the decision. Shamji and Durham in JACI 2017 identified 7 biomarker domains relevant to immunotherapy outcomes: allergen-specific IgG4 (rising during treatment, serves as a functional blocking antibody), IgE-to-IgG4 ratio (decreasing ratio correlates with tolerance), basophil activation test responses (declining), skin test reactivity (reduced), and regulatory T-cell markers. Reduced skin test reactivity at the end of a SCIT course is a commonly used practical indicator of immune tolerance. Your allergist may use a combination of symptom assessment and selective biomarker testing to inform the stopping decision.