Peanut Allergy in U.S. Adults: On the rise?

Sherry Coleman Collins, MS, RDN, LD
In February, a new study was published showing a significant rise in the numbers of adults with peanut allergy in the U.S. This study, based on a phone and web survey of 40,443 adults in the U.S., was conducted between 2015 and 2016. According to the researchers, self-reported peanut allergy among U.S. adults is now as high as 2.9%. However, when responses were further reviewed, 1.8% were considered “convincing peanut allergy”, a designation given when the reported symptoms were consistent with an IgE mediated reaction. In addition, 17% of these respondents indicated that they developed their allergy in adulthood. Although the number of those reporting peanut allergy is small, compared to the vast majority of respondents who did not report a food allergy, it represents more than a doubling since the NIAID Guidelines for the Diagnosis and Management of Food Allergy in the United States was released in 2010 and said the prevalence was 0.6%. Another study, published in 2012, cited the prevalence of peanut allergies around 1.3%.
So, what’s going on? That’s a great question and one that we don’t have a definitive answer for, but the researchers indicated that some of the increase is due to the increase in pediatric peanut allergy. While up to 20% of children with peanut allergy will outgrow it, most will not, leading to more adults with peanut allergies. Hopefully, early introduction of peanut foods in infancy will significantly reduce the number of infants who go on to develop peanut allergy.
As for the adults who reported developing peanut allergy in adulthood – we know that allergies can develop at any time in the lifecycle. It’s possible that food allergies in adulthood were previously not reported as frequently, since adults may feel comfortable simply avoiding foods that don’t agree with them. However, it’s important to recognize that in this sample, reported reactions were similar between adults and children, yet less than half of the adults with reported peanut allergy carried emergency epinephrine to treat severe reactions.
A significant limitation to this study is that the data is self-reported. According to the NIAID Guidelines, 50-90% of self-diagnosed food allergies are wrong. Recall bias is always an issue with self-reported information and it is a limitation for this study as well. There has been an increase in awareness about food allergies, along with the proliferation of at-home tests for food sensitivities, which together could result in over-reporting of food allergies in general. In the case of this study, there were no corresponding objective tests or oral food challenges utilized to confirm the reported peanut allergies.
While these new numbers are reason to pay attention to adult food allergies, it is also important to keep them in perspective. Know that there are limitations to the data. The good news is that most people can and do enjoy peanut foods without any adverse reactions.

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