Epinephrine use less common in adult- vs childhood-onset peanut allergy

Adults who develop peanut allergy in adulthood are less likely to receive a physician diagnosis of their allergy or use epinephrine compared with those with childhood-onset peanut allergy, according to a study from the US.

Between 2015 and 2016, 40,443 adults answered phone- and web-based cross-sectional surveys on food allergies. Of these, 2.9 percent reported having peanut allergy, with 1.8 percent considered convincing (symptoms consistent with IgE-mediated reactions to the particular food) and 1.3 percent being diagnosed by a physician.

Among individuals with physician-diagnosed peanut allergy, 14.3 percent developed their allergy in adulthood with peak prevalence at age 30–39 years (2.9 percent). Physician diagnosis of peanut allergy was more common among individuals who developed their allergy in childhood than adulthood (75.4 percent vs 58.9 percent). [AAAAI 2020, abstract 455]

Emergency department visits for food-related allergies in the previous year occurred at a similar rate between individuals with adult- and childhood-onset peanut allergy (18.2 percent vs 20.2 percent). However, individuals with childhood-onset peanut allergy were more likely to have a current prescription for epinephrine than those with adult-onset peanut allergy (55.8 percent vs 43.8 percent; p=0.02). The use of epinephrine auto-injectors was also significantly more common among individuals with childhood-onset compared with adult-onset peanut allergy (48.1 percent vs 35.1 percent; p=0.01).

“While peanut allergy is a well-known cause of anaphylaxis and is well-studied, particularly in a paediatric population, less is known about how prevalent peanut allergy is in adults,” said study author Professor Ruchi S. Gupta from the Northwestern Medicine Feinberg School of Medicine, Chicago, Illinois, US. “We wanted to examine not only the prevalence but the characteristics of peanut allergy in adult populations compared to paediatrics to see what similarities and differences occur.”

With approximately 5.8 million adults in the US having peanut allergy, more than 800,000 would have developed their allergy in adulthood, noted the researchers of the study which was initially scheduled for presentation at AAAAI 2020.

“The next step is to determine whether there are important phenotypic differences in peanut allergy between childhood-onset and adult-onset cases,” said study co-author Dr Christopher Warren from the University of Southern California, Los Angeles, California, US.

“If key differences are discovered, it could improve our understanding of factors that may precipitate adult peanut allergy which in turn can advance food allergy prevention efforts and improve disease management for patients. In the meantime, we hope this prevalence study helps to inform the public about the increasing ubiquity of adult-onset peanut allergy and the importance of consulting an allergist/immunologist to definitively diagnose any suspected food allergies,” he said.