How Allergy Immunotherapy Works | WhatAreAllergies.com
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Medically reviewed by Dr. Sarah Jenkins, MD, FACAAI

Verified Reviewer

Board Certified Allergist & Immunologist · Clinical Allergy, Asthma & Immunology

Stanford University School of Medicine

Updated March 2026·Annual review cycle

Our editorial process: All content on WhatAreAllergies.com is written by medical writers and reviewed by board-certified allergists and immunologists. We follow ACAAI, AAAAI, WAO, and ARIA clinical guidelines. Content is updated on an annual review cycle or when major guidelines change. We do not accept advertising influence on editorial content. Read our editorial policy →

Allergy Treatment Escalation Ladder — From Environmental Control to Biologic Therapy

← Start here (most patients)Specialist-managed (severe cases) →
Allergy treatment escalation ladder adapted from ARIA Guidelines and AAAAI Treatment Algorithms 2025. Treatment selection requires clinician evaluation.

Disease Modification, Not Just Symptom Suppression

Unlike antihistamines and nasal corticosteroids which only manage symptoms temporarily, Allergen Immunotherapy (AIT) fundamentally shifts the immune system's response. By exposing the patient to gradually increasing doses of the allergen, the body shifts from producing allergic IgE antibodies to protective IgG4 blocking antibodies.

Forms of Allergen Immunotherapy

  • Subcutaneous Immunotherapy (SCIT): Traditional allergy shots administered at an allergist's office. The most extensively studied form with a 100+ year evidence base.
  • Sublingual Immunotherapy (SLIT): Allergen extract administered as drops or FDA-approved tablets under the tongue. More convenient (can be done at home) but generally considered slightly less efficacious than SCIT for some allergens.
  • Oral Immunotherapy (OIT): A breakthrough treatment for food allergies, particularly peanut. FDA-approved Palforzia has demonstrated ability to raise the reaction threshold significantly in children.

Prerequisite for immunotherapy: accurate allergen identification through allergy testing. Read our allergy research trends 2026 to learn about emerging biologic combinations with AIT.

Candidacy criteria adapted from AAAAI/ACAAI Practice Parameters. Final determination requires allergist evaluation.

Frequently Asked Questions

How long does immunotherapy take to work?
Most patients notice improvement in their first allergy season (4-6 months into treatment). Optimal benefit is typically reached after 12-18 months of regular maintenance injections. Treatment is usually continued for 3-5 years to achieve long-lasting tolerance.
Is immunotherapy available for food allergies?
Yes. Oral immunotherapy (OIT) is now FDA-approved for peanut allergy (Palforzia) in children aged 4-17. OIT for milk, egg, and other foods is available at specialized centers. Read our dedicated OIT guide for detailed protocols.
What is the difference between allergy shots and sublingual immunotherapy?
Allergy shots (SCIT) are administered by injection in a clinic and have the longest evidence base. Sublingual immunotherapy (SLIT) uses drops or tablets placed under the tongue and can be done at home. Both work via the same immune tolerance mechanism.

About the Medical Team

SJ
Medical Review

Dr. Sarah Jenkins, MD, FACAAI

Board Certified Allergist & Immunologist

Clinical Allergy, Asthma & Immunology

Stanford University School of Medicine
MC
Written by

Dr. Michael Chen, MD, PhD

Clinical Immunologist & Researcher

Translational Immunology, Biologic Therapies

Johns Hopkins University

All contributors hold active board certification in allergy, immunology, or a related specialty. View full credentials →

Medical References & Citations

  1. 1
    guideline2006

    Sampson HA, et al. "Second symposium on the definition and management of anaphylaxis: Summary report" — Journal of Allergy and Clinical Immunology.

    View source
  2. 2
    database2025

    American College of Allergy, Asthma & Immunology (ACAAI) "Allergy Facts and Figures" — ACAAI Clinical Resources.

    View source
  3. 3
    review2025

    World Allergy Organization (WAO) "White Book on Allergy — 2025 Update" — World Allergy Organization.

    View source
  4. 4
    guideline2024

    National Institute of Allergy and Infectious Diseases (NIAID) "Clinical Guidelines for the Diagnosis and Management of Food Allergy" — National Institutes of Health.

    View source
  5. 5
    guideline2024

    Muraro A, et al. "EAACI food allergy and anaphylaxis guidelines: Diagnosis and management of food allergy" — Allergy — European Journal of Allergy and Clinical Immunology.

This content reflects clinical guidelines current as of the last review date shown above. Always consult a qualified healthcare provider for personalized medical advice.