• A new study found that peanut allergy may be more prevalent among U.S. adults than previously thought
  • Some adults develop a peanut allergy after the age of 18
  • Those who develop peanut allergy as adults are less likely to be diagnosed by a physician

A team of researchers found that peanut allergy is actually quite common among adults. But the adults who have them tend to not get diagnosed for it.

People often think of peanut allergy as a condition that primarily afflicts children. Considered as one of the most common food allergies among children in the U.S., only about 20% of those who have a peanut allergy eventually outgrow it, the American College of Allergy, Asthma & Immunology (ACAAI) said.

However, not much is known about the prevalence of peanut allergy among adults. In a new study published in The Journal of Allergy and Clinical Immunology, a team of researchers sought to describe the burden of peanut allergy among adults in the U.S.

For the study, they conducted phone and online surveys with 40,443 adults. The results suggest that about 4.6 million adults have a "convincing" peanut allergy, with one in six of them (over 800,000) having developed the allergy after the age of 18. In fact, the mean age that the people with adult-onset peanut allergy experienced a peanut-allergic reaction was found to be 33 years old.

Those who reportedly developed the allergy in adulthood, however, were much less likely to get diagnosed by a physician compared to those who develop it as children.

"In adults with childhood-onset PA, 75.4% reported physician-diagnosed PA, compared with only 58.9% of adult-onset PA," the researchers wrote.

Representative image of peanuts. Alexas Fotos/Pixabay

Dr. Ruchi Gupta, director of the Center for Food Allergy and Asthma Research at Northwestern University in Illinois and co-author of the study, explained to CNN that adults who have had a reaction to certain foods tend to avoid it instead of getting an allergy test to confirm the allergic reaction.

"They could be living their life as if their next bite could lead to a very bad outcome when it's something that would be so easy to avoid," study co-author Christopher Warren of the Center for Food Allergy and Asthma Research told the outlet.

What's more, the researchers found that even if the severity of the allergic reactions were similar in childhood-onset and adult-onset peanut allergy sufferers, only 44% of those with adult-onset allergy had an epinephrine prescription compared to 56% of the adults with a childhood-onset peanut allergy. Instead, those with adult-onset peanut allergy were more likely to use antihistamines instead of an epinephrine shot.

This is relevant because, as the researchers noted, the peanut is the leading cause of fatal and near-fatal anaphylaxis.

"Epinephrine remains the first-line treatment for anaphylaxis, making it exceedingly concerning that the majority of patients with adult-onset PA and just under one-half of patients with childhood-onset PA do not report a current EAI prescription," the researchers wrote.

According to the researchers, their work shows that there are more U.S. adults with a peanut allergy than previously thought.

"Further examination of phenotypic differences between childhood-onset and adult-onset PA may improve understanding and management of adult PA," the researchers added.

For now, the ACAAI is advising those who suspect that they are allergic to peanuts to make an appointment with an allergist and to start a food diary to track their reactions.