When Allergy Shots Start Working
Patients typically begin experiencing symptom relief from allergy shots within 3-6 months of starting treatment, with maximum clinical benefit achieved within 1-2 years of continuous therapy. 1
Timeline of Clinical Response
Initial Build-Up Phase (4-6 months)
- The build-up phase involves 1-2 injections per week with gradually increasing allergen doses 2
- Most patients reach maintenance dosing within 4-6 months, depending on starting dilution and tolerance 2
- Some symptom improvement may begin during this phase, but therapeutic effect is not yet established 1
Early Therapeutic Response (2-4 months of treatment)
- Clinical efficacy typically begins after 2-4 months of immunotherapy 1
- This represents the minimum timeframe to assess whether treatment is working 1
- Immunologic changes (increased IL-10, allergen-specific IgG4) occur within weeks, but clinical symptoms lag behind 1
Maximum Benefit (1-2 years)
- Peak clinical effectiveness is achieved within 1-2 years of continuous treatment 1
- If no improvement occurs by 2 years despite optimal patient selection and compliance, discontinuation is reasonable 1
- This timeline applies to both subcutaneous and sublingual immunotherapy 1
Important Clinical Considerations
Treatment Duration for Long-Term Tolerance
- A minimum of 3 years of continuous immunotherapy is required to achieve disease modification and sustained tolerance after treatment stops 3, 1, 4, 5
- Shorter courses (less than 3 years) provide temporary benefit but fail to induce long-lasting tolerance 5
- After 3-5 years of therapy, clinical benefits persist for years following discontinuation 3, 4
Factors Affecting Response Time
- Patient sensitivity level influences both starting dose and time to therapeutic effect 2
- Allergen exposure levels during treatment affect clinical response 1
- Treatment compliance is critical—missed injections delay reaching maintenance dosing 1
Common Pitfall to Avoid
Do not discontinue therapy prematurely if patients don't see immediate results. Counsel patients at initiation that symptom relief requires patience, typically 3-6 months minimum, and that stopping before 3 years prevents long-term disease modification 3, 1, 5. Unlike antiallergic medications that work within hours to days, immunotherapy fundamentally alters the disease course but requires sustained commitment 3, 6.