Is it possible for an allergy to crested wheatgrass to develop later in life?

Allergic reactions generally occur when your immune system reacts abnormally to certain substances, known as allergens. In this case, the allergen you've specified is crested wheatgrass. The interesting thing about allergies is that they can develop at any time throughout your life, not just during childhood. This includes later in life, regardless of whether you've had many prior periods of exposure to the allergen without any adverse reactions.

With respect to allergies to grasses, such as crested wheatgrass, the typical way people become allergic is through repeated exposures over time. The immune system may, upon numerous exposures, suddenly start to recognize the grass pollen as a threat and generate an immune response, causing symptoms like itching, sneezing, runny nose, and watery eyes.

Further, the severity of the allergy can also change over time. Allergies can get worse with more exposures, but in some cases, they may also lessen over time, especially if you are not exposed to the allergen for a while.

In terms of managing new-onset allergies, it includes allergen avoidance (if feasible), symptomatic relief with medications like antihistamines, and potentially immunotherapy which is a more long-term solution for some people. However, it's crucial to understand your personal scenario better, keep track of your symptoms, and consult your healthcare provider for personalized advice.

To conclude, while primarily allergies begin in childhood, it's not uncommon for new allergies to manifest in adulthood including allergy to crested wheatgrass.