Allergies are a misguided response by the body’s defense system, mistakenly identifying a harmless substance (an allergen) as a threat. This overreaction triggers the release of chemicals like histamine, causing familiar symptoms such as sneezing, itching, and congestion. While the question of whether allergies worsen with age is complex, allergic responses frequently change significantly over a person’s lifespan. These immune system changes are not always linear, meaning an allergy may improve, disappear, or newly develop, rather than simply getting worse over time.
The Biological Basis for Changing Allergies
The body’s ability to recognize and respond to foreign substances shifts as the years pass. This gradual deterioration of the immune system is known as immunosenescence, which alters how the body manages inflammation and allergic triggers. A key mechanism involves the thymus, which produces T cells crucial for regulating immune responses. The thymus shrinks rapidly after puberty, reducing the output of new T cells capable of identifying novel threats.
This reduced immune flexibility is linked to chronic, low-level inflammation throughout the body, sometimes called “inflammaging.” The immune system becomes less efficient at distinguishing between genuine pathogens and benign allergens, leading to increased sensitivity. Older individuals may also experience a shift toward immunity that promotes the production of IgE antibodies, the primary drivers of allergic reactions. These biological shifts make the body more generally reactive, setting the stage for altered or new allergic symptoms.
The Development of New Adult-Onset Allergies
A significant aspect of aging is the potential for allergies to appear for the first time in adulthood, long after childhood. These de novo allergies are distinct from persistent childhood conditions and can manifest in various forms. Food allergies are a common example, with nearly half of all adults who report a food allergy developing at least one of them later in life.
New environmental exposures also play a role, such as moving to a different geographic region or workplace that introduces novel pollen or mold spores. Common adult-onset triggers include:
- Shellfish
- Tree nuts
- Finned fish
- Medications, such as antibiotics or nonsteroidal anti-inflammatory drugs (NSAIDs)
Trajectories When Allergies Worsen, Improve, or Disappear
For individuals with existing allergies, the condition can follow one of several distinct paths. Some people experience a worsening of existing symptoms, often seen with seasonal allergies like hay fever. This increase in severity can be due to prolonged exposure or environmental factors, such as extended pollen seasons driven by climate change. Additionally, some adults develop Oral Allergy Syndrome, reacting to raw fruits or vegetables because the immune system cross-reacts with proteins similar to those found in pollen.
Other allergies may follow a trajectory of persistence, remaining relatively stable in severity and frequency throughout life, requiring consistent management. Conversely, some individuals may experience an improvement or even the disappearance of certain allergies. The severity of an allergy can diminish later in life, particularly in advanced age, because overall immune system activity slows down. This reduction in activity can result in a less pronounced IgE antibody response, leading to milder or less frequent allergy symptoms. Any dramatic change in symptoms warrants a re-evaluation by an allergy specialist due to the potential for a severe reaction like anaphylaxis.