Survey says: More Americans think they have food allergies than actually do

Although nearly 19% of US adults believe that they have at least one food allergy, only an estimated 10.8% actually do, according to results of a survey published in JAMA Network Open.

“Food allergy is a costly, potentially life-threatening condition,” wrote authors led by Ruchi S. Gupta, MD, MPH, Institute for Public Health and Medicine, Northwestern University Feinberg School of Medicine, Chicago, IL. “Although studies have examined the prevalence of childhood food allergy, little is known about prevalence, severity, or health care utilization related to food allergies among US adults.”

Researchers have estimated the prevalence of food allergies in children, but it remains less well quantified in adults. Nevertheless, estimates from secondary analyses of recent national surveys have pegged the prevalence of food allergies in adults at greater than 9%, which is higher than previously thought by experts.

Some children remain allergic to foods when they become adults; whereas, some children with food allergies outgrow them and develop natural tolerance. Moreover, some adults develop new food allergies. Indeed, certain food allergies—such as shellfish and fin fish—are more prone to crop up during adulthood. Finally, researchers have found an increasing rate of food allergy-related emergency department (ED) visits among children and young adults.

To further understand the distribution, severity, and factors associated with US adult food allergy, Dr. Gupta and colleagues surveyed 40,443 adult Americans. The primary outcomes in the study were self-reported food allergies, which were considered convincing if reported symptoms resulted from IgE-mediated reactions. Other outcomes included specific allergen diagnosis history and health-care utilization related to food allergy.

The team found that convincing food allergy prevalence among US adults was 10.8% (95% CI, 10.4% to 11.1%) vs 19.0% (95% CI, 18.5% to 19.5%) of adults who self-reported at least one food allergy. The most frequent convincing food allergies were shellfish (2.9%; 95% CI, 2.7% to 3.1%), milk (1.9%; 95% CI, 1.8% to 2.1%), peanut (1.8%; 95% CI, 1.7% to 1.9%), tree nut (1.2%; 95% CI, 1.1% to 1.3%), and fin fish (0.9%; 95% CI, 0.8% to 1.0%).

Among food-allergic adults, 51.1% (95% CI, 49.3% to 52.9%) sustained a severe food allergy reaction, and 45.3% (95% CI, 43.6% to 47.1%) exhibited allergy to multiple foods. Of note, 48.0% (95% CI, 46.2% to 49.7%) developed food allergies during adulthood.

With respect to health-care utilization, 24.0% (95% CI, 22.6% to 25.4%) of Americans surveyed reported a current epinephrine prescription (Epipen), and 38.3% (95% CI, 36.7% to 40.0%) noted at least one food allergy-related lifetime emergency department (ED) visit.

In other terms, results from the study suggest that at least 13 million food-allergic American adults have experienced at least one severe food-allergic reaction, with at least 12 million adults exhibiting adult-onset food allergy. At least 10 million adults have visited the ED secondary to food allergy.

While the authors recommended that all adults with food allergies be prescribed epinephrine, they found that only about one-quarter of food-allergic adults surveyed had actual prescriptions. Specifically, those with severe allergic reactions and lifetime-history of ED visits for allergic reactions were most likely to have an epinephrine prescription.

One limitation of this study is that it was based on self-reported survey results. Although impractical, the best approach to measure food allergy in adults is double-blinded, placebo-controlled oral food challenges. To ensure the accuracy of results, the researchers asked expert-reviewed questions linked to IgE-mediated food allergy.

“The results of our study suggest that adults need to be encouraged to see their physicians to receive proper diagnosis, epinephrine prescription, and counseling for their food allergy,” concluded Dr. Gupta and fellow researchers. “Given the increasing evidence for the preventive benefits of early allergen exposure during infancy and potential treatment options, adults should be made aware of these new practices to potentially prevent food allergies in their children or consider treatments in the near future.”