Many people believe that once an allergy develops in adulthood, it is a permanent condition. While this can often be the case, the reality of allergy persistence and resolution in adults is more nuanced than a simple lifelong diagnosis.
Understanding Allergy Persistence in Adulthood
Allergies that begin in childhood, particularly food allergies, frequently resolve as a child grows older. However, allergies that emerge in adulthood or those that persist from childhood tend to be more stable. The immune system develops a strong memory of allergens, primarily through the production of specific immunoglobulin E (IgE) antibodies and memory B cells. These IgE antibodies bind to mast cells, priming the body for a rapid allergic reaction upon re-exposure to the allergen. This immune memory contributes to the persistence of allergies in adults. Adult-onset allergies are common, and nearly half of adults with food allergies developed at least one in adulthood, but these tend to be less likely to disappear.
Specific Allergies and Their Resolution Potential
The likelihood of an allergy resolving in adulthood depends on the type of allergen. Allergies to certain foods, such as milk, egg, wheat, and soy, are more commonly outgrown during childhood and adolescence. However, if these allergies persist into adulthood, their resolution becomes less probable.
Conversely, allergies to peanuts, tree nuts (like almonds, walnuts, pecans, and cashews), fish, and shellfish are more persistent and rarely resolve in adulthood. For instance, while about 20% of children with peanut allergies may outgrow them, the majority will carry this allergy throughout their adult lives. Similarly, tree nut allergies are even less likely to resolve, with fewer than 10% of affected individuals experiencing resolution. Shellfish and fish allergies are often lifelong, appearing in adulthood and persisting. Drug allergies and venom allergies are also typically considered permanent once established.
The Biology Behind Allergy Resolution
Allergy resolution involves complex changes within the immune system, leading to a state of immune tolerance. This tolerance means the body no longer mounts an allergic reaction to a substance it once perceived as a threat. One key mechanism involves a shift from an IgE-mediated response, which is characteristic of allergic reactions, to non-allergic immune responses. This can include a reduction in IgE levels and an increase in other antibody types, such as IgG4, which do not trigger allergic symptoms.
Regulatory T cells (Tregs) play a role in maintaining immune tolerance to allergens. These cells help to suppress the immune system’s overactive response to harmless substances. Allergen-specific immunotherapy, which involves controlled exposure to increasing amounts of an allergen, can induce the development of these regulatory T cells, promoting tolerance and reducing allergic symptoms.
Navigating Potential Allergy Resolution
If an adult suspects their allergy may have resolved, it is important to seek professional medical guidance. Self-testing for allergies is strongly discouraged due to the risk of severe allergic reactions, including anaphylaxis. Online allergy tests or at-home kits often provide unreliable results and can lead to incorrect self-diagnosis or unnecessary dietary restrictions.
An allergist or healthcare professional can perform appropriate tests to assess allergy status. These may include blood tests to measure specific IgE levels or skin prick tests. The “gold standard” for confirming allergy resolution, especially for food allergies, is a medically supervised oral food challenge. During this challenge, increasing amounts of the suspected allergen are consumed in a controlled medical setting, with immediate access to emergency treatment if a reaction occurs.