Doctors Say Adults Can Develop New Food and Environmental Allergies at Any Age

CLEVELAND, OH — For decades, prevailing medical wisdom suggested that if you did not sneeze through hay fever as a kid, you were likely in the clear for the rest of your life. Local experts say that is a misconception that often leaves patients confused when they suddenly develop symptoms in their 30s, 40s or even later. Adults are increasingly walking into clinics with brand-new reactions to things they have eaten or breathed for a lifetime. "Patients can develop allergies as adults, including both environmental and food allergies," explained Dr. Sandra Hong, an allergist at the Cleveland Clinic. It is not just a matter of catching an allergy like one might catch a cold. Instead, it is a shift in the immune system’s loss of immunological tolerance. For reasons researchers are still investigating, the body may suddenly misidentify a previously harmless protein, such as those found in birch pollen or shellfish, as a dangerous pathogen. This triggers the production of immunoglobulin E antibodies. This sensitization phase can occur silently over many years, building up an internal defense until the symptoms finally manifest abruptly. Environmental factors are a primary driver in these late-stage developments, particularly when people relocate. When someone moves to a new climate like Northeast Ohio, they are introduced to novel fungal spores and local flora their immune system has not encountered before. According to findings from the Cleveland Clinic, it often takes three to five years of living in a new environment for the immune system to become sensitized enough to display overt symptoms such as chronic congestion. Because of this delay, many people misdiagnose their own allergies as recurring colds or sinus infections. The landscape of adult-onset food allergies is equally distinct. Research published in the journal JAMA Network Open suggests that nearly half of all food-allergic adults developed at least one of their allergies during adulthood. Unlike children, who frequently outgrow sensitivities to milk or eggs, adults who develop an allergy to shellfish, tree nuts or peanuts rarely see the condition resolve itself. Dr. Hong noted there is no single cause for this, but something as simple as trying a new food or a change in routine can be enough to trigger the immune response. In some cases, it is a result of oral allergy syndrome. This is a cross-reactivity in which the immune system confuses the proteins in certain raw fruits or vegetables with those in environmental pollens. A person with a long-standing ragweed allergy might suddenly find their throat itching after eating melons or bananas. Risk factors are not limited to genetics, though a family history of allergies, asthma or eczema makes an individual more vulnerable. There is also emerging evidence regarding the role of the gut microbiome. Disruptions caused by heavy antibiotic use or significant changes in diet can alter the intestinal barrier, potentially allowing undigested proteins to enter the bloodstream. Major hormonal transitions, such as pregnancy or menopause, can also recalibrate immune responses and lead to the sudden onset of sensitivities. "If someone notices symptoms like itching, sneezing, congestion or drainage happening around the same time every year, that’s a good reason to see an allergist," Dr. Hong said. Diagnosis for adults requires a nuanced approach because the symptoms can mimic other chronic conditions. While itching and hives are classic markers, board-certified allergists also look for frequent sinus headaches or recurring coughing as primary indicators of an underlying trigger. Doctors typically use skin-prick testing and serum-specific blood tests to pinpoint the exact cause of the reaction. Management often involves a combination of environmental avoidance and intranasal corticosteroids, though some patients may require allergen immunotherapy to retrain their immune system. Patients who suspect they are developing new sensitivities can contact the Cleveland Clinic Allergy and Clinical Immunology Department to schedule a diagnostic consultation. -------------------- At Cleveland 13 News, we strive to provide accurate, up-to-date, and reliable reporting. If you spot an error, omission, or have information that may need updating, please email us at tips@cleveland13news.com. As a community-driven news network, we appreciate the help of our readers in ensuring the integrity of our reporting.