Allergy Immunotherapy Explained: How Allergy Shots Work and What to Expect

Overview

In this NPR Shortwave episode, Regina Barber chats with allergist Dr. Gina Depool Hidalgo about what causes allergies, how clinicians diagnose them, and a long-standing treatment option that goes beyond masking symptoms: allergen immunotherapy, or allergy shots. The discussion covers how allergies begin with IgE antibodies, how skin testing reveals sensitivities, and how therapy can train the immune system to react more calmly to common allergens. The episode also touches on food allergies, food-avoidance guidance, and the history of allergy shots dating back more than a century.

Key Points

Listeners learn about the two phases of immunotherapy, the potential (yet rare) side effects, and the long-term outlook for symptom relief. The host team also highlights the evolving landscape of allergy management, including the contrast between inhalant allergies and food allergies and the evolving guidance on early exposure to allergenic foods.

Introduction and Context

This NPR Shortwave episode features Regina Barber in a conversation with pediatric and adult allergist Dr. Gina Depool Hidalgo about how allergies arise and how they are managed beyond symptom relief. The discussion anchors on the immune mechanism behind allergic responses, specifically the role of IgE antibodies and histamine release, which drive typical allergy symptoms such as sneezing and congestion. The guest explains that while many patients are sensitized to allergens, not all experience clinical reactions, and that tolerance can develop with frequent exposure in some cases.

One of the central topics is allergen immunotherapy, commonly known as allergy shots. The guest outlines how this treatment works by exposing the immune system to gradually increasing amounts of the allergen, with the aim of desensitizing the response over time. The dialogue covers the two main phases—the buildup phase with weekly injections and a maintenance phase every few weeks—and notes that a typical course lasts several years, often 3 to 5 years, with long-lasting effects but no guaranteed cure.

Quote: There is no cure for allergies per se, which is why management and long-term strategies matter. This emphasis on realistic outcomes frames the discussion about what patients can expect from therapy and how it may affect quality of life over time.

Beyond inhalant allergens, the program explores food allergies and the fact that foods are not treated with injections. Instead, oral immunotherapy is used in some cases to introduce small, controlled amounts of the offending food, under medical supervision. A landmark shift in public health guidance is discussed, notably the 2015 peanut trial showing that early introduction of peanut between 4 and 6 months reduced peanut allergy in high-risk infants, a finding that has influenced pediatric guidance for over a decade.

The segment also touches on safety, including the potential for localized reactions at the injection site and, rarely, systemic or anaphylactic reactions, which are mitigated by monitored administration and trained staff. Throughout, the episode blends clinical details with historical context, noting allergy shot origins dating to 1911 with Leonard Noon’s early experiments and subsequent advances in purified allergen extracts. The conversation closes with reflections on how allergy management has evolved and how patients, families, and clinicians navigate decision-making in the face of evolving evidence and practical realities.

Quote: Allergy shots are actually training your immune system to react differently when you're exposed to the allergens. - Dr. Gina Depool Hidalgo