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Many patients develop food allergy in adulthood, yet often go undiagnosed

About a quarter of individuals develop a food allergy after the age of 18 years, but are not frequently diagnosed by physicians, according to findings presented at the American College of Allergy, Asthma and Immunology Annual Scientific Meeting.

Prevalence of adult-onset food allergy

“While much attention has been devoted to food allergy in children, little is known about the prevalence and characteristics of food allergy in adults,” Christopher Warren, PhD candidate in the department of preventive medicine at the University of Southern California Keck School of Medicine, and colleagues wrote. “Moreover, recent research has shown that increasing numbers of individuals are developing food allergy in adulthood.”

Between 2015 and 2016, Warren and colleagues administered a survey to 40,443 adults in the United States to investigate the prevalence, severity and distribution of adult-onset food allergy. The researchers used complex survey weighting to estimate population-level prevalence. They also assessed participants’ demographics, history of reactions and diagnosis for each allergen and comorbid conditions.

Overall, 45.3% of adults with food allergy reported developing at least one food allergy in adulthood. A quarter of participants with food allergy reported experiencing onset of allergy only in adulthood and 54.7% reported experiencing onset of allergy only in childhood.

Shellfish (13.3%), milk (6%), wheat (5.6%), tree nut (4.8%) and soy (3.9%) were the most common adult-onset food allergies. Of the participants with adult-onset allergy to peanut, tree nut, fin fish or shell fish, more than 50% experienced a severe reaction to the allergen beforehand.

Females, older adults and patients with a history of multiple food allergies, allergic rhinitis or medication allergy were associated with developing adult-onset food allergy.

“One in four adults with food allergy develop a food allergy for the first time as an adult,” Warren and colleagues concluded. “Further study is necessary to understand potential predictors of adult-onset food allergy.”

Physician diagnosis of adult-onset food allergy

“Food allergy is a life-threatening health condition that continues to increase in prevalence, yet knowledge regarding diagnosis and management of adult food allergy is limited,” Gabriel Peirats Moore, BA, from the Center for Community Health at Northwestern Feinberg School of Medicine, and colleagues wrote.

Moore and colleagues also administered a survey between 2015 and 2016 to the same dataset of patients to determine the practices of physicians in diagnosing food allergy in adults. Stringent symptom criteria were used to differentiate adults with “convincing” food allergy from those with similar conditions, such as food intolerance or oral allergy syndrome.

The researchers found that physicians did not diagnose about half (95% CI, 48.6-51.9) of convincing food allergy.

Males, adults with seasonal allergy, severe food allergy and multiple food allergies were significantly more likely to be diagnosed by a physician. The likelihood of being diagnosed by a physician was significantly lower among adults who were a part of a family that earned less than $50,000. Adults in families earning between $50,000 and $100,000 were more likely to receive a physician diagnosis.

Most food allergies that were diagnosed by a physician were assessed with a skin prick test (70.2%; 95% CI, 67.9-72.5), followed by an IgE test (47.4%; 95% CI, 44.9-49.8) and an oral food challenge (30.3%; 95% CI, 28.1-32.6).

“Adults with convincing food allergy are not frequently receiving physician diagnoses,” Moore and colleagues concluded. “This suggests a higher perceived burden of food allergy that may result in unnecessary avoidance of food and impaired quality of life.” – by Alaina Tedesco

References:

Moore GP, et al. Abstract P313. Presented at: American College of Allergy, Asthma and Immunology Annual Scientific Meeting; Nov. 15-19, 2018; Seattle.

Warren C, et al. Abstract A311. Presented at: American College of Allergy, Asthma and Immunology Annual Scientific Meeting; Nov. 15-19, 2018; Seattle.

Disclosure: Please see the meeting’s abstract book for the authors’ relevant financial disclosures.