Expanding early peanut introduction can increase prevention efforts

Early peanut introduction has been recommended to pre-emptively address peanut allergies in at-risk children with positive skin prick tests for some time now, but a new study reveals the potential of peanut introduction as a preventive tool in other groups, as well.

The Learning Early About Peanut Allergy (LEAP) trial and other studies have shown the benefit of early peanut introduction in helping children aged younger than 5 years who are at-risk of developing a peanut allergy. However, these studies have excluded infants whose skin prick tests were greater than 4 mm. Additionally, current guidelines for early peanut introduction recommend oral food challenges only in infants who have skin prick tests ≤7 mm. There is no guidance for infants whose skin prick tests are >7 mm or who have high peanut immunoglobulin E (IgE) levels. Adding to the difficulty in addressing oral food challenges in these populations is the lack of standardized values for skin prick testing and IgE levels in infants with peanut allergies.

A new study, published in the Annals of Allergy, Asthma, and Immunology, sought to test oral food challenges in a wider group than had previously been allowed under current guidelines.¹ Specifically, the research team investigated whether smaller, 1-gram doses of peanut would be tolerated in children who typically are not offered oral food challenges.

“We've seen that strict avoidance at a young age does not prevent peanut allergy and may promote it in some at-risk children,” says lead author Adora A. Lin, MD, PhD, FAAAAI, principal investigator for the Center for Cancer and Immunology Research at the Children’s National Research Institute and attending physician at Children’s National Hospital in Washington, DC. “The exact mechanisms are unknown, but the general idea is that allergen exposure through the gut can lead to a tolerizing immune response, whereas allergen exposure through the skin—especially eczema-inflamed skin—can lead to an allergic immune response. We see low dose peanut introduction as a strategy to allow more children get peanut in the diet at a young age to hopefully prevent peanut allergy.”

From an allergist's perspective, many allergists are fearful to offer peanut food challenges to infants with larger peanut skin prick tests, and require them to consume doses larger than 1 gram to "prove" that they are not allergic, Lin reveals.

“We see peanut food challenges with a lower dose as an opportunity to facilitate peanut introduction in some at-risk patients,” she says.

Lin referenced a 2019 survey that showed several barriers to peanut introduction in infants, including fear of reactions, choking, and a lack of infant-safe forms of peanut.

“In the same survey, only 60% of physicians provided recommendations consistent with National Institute of Allergy and Infectious Disease (NIAID) guidelines, with physician-perceived barriers of parental acceptance of guidelines and fear of giving peanut, and identified educational handouts and access to infant-safe forms of peanut as needed resources,” Lin says. “The data suggest that both families and physicians would benefit from further education on practical aspects of peanut introduction.”

The research team tested the tolerance of a one-gram peanut challenge in infants regardless of skin prick test size or peanut IgE results over a 2-year period in the retrospective study. Of the infants with a skin prick test equal to or smaller than 4 mm, 97% were tolerant of low-dose challenges. In children with skin prick tests larger than 4 mm, 63% were low-dose tolerant. Additionally, the researchers found that Ara h2 IgE levels were significantly lower in the children who did well with the tests compared to those who were not tolerant to the oral challenge. This suggests that Ara h2 IgE levels might be predictive to tolerance of oral food challenges in some infants, the study notes. In this regard, the study concludes that low dose peanut oral food challenges with a gradual increase in dosing may help prevent peanut allergies in a larger number of children at risk of developing these allergies.

“Current NIAID guidelines for early peanut introduction recommend peanut introduction or supervised oral food challenge for infants with peanut skin prick tests ≤7 mm in size and do not specifically address management of infants with peanut skin prick tests ≤7 mm,” Lin says. “Based on previous studies, these infants are typically advised to avoid peanut. However, in our study, we showed that over 50% of these infants can tolerate a low dose of peanut and can increase the dose at home.”

This means that supervised introduction of a low dose of peanut can be done safely for a wider population of infants than previously thought—potentially benefiting a larger population of infants—and that families can gradually increase the dose of peanut their infants eat at home, Lin says.

“Multiple studies have provided evidence that early introduction of peanut can decrease the incidence of peanut allergy, leading to guidelines from NIAID, the American Academy of Pediatrics, and clinical organizations around the world to recommend early introduction of peanut. However, due to certain risk factors and test results, many physicians may be hesitant to offer introduction of peanut to certain infants,” Lin notes. “In addition, infants developing feeding skills and preferences may have difficulties eating larger quantities of solid food. We encourage allergists to consider offering supervised introduction of peanut to infants with large peanut skin prick tests, and present the low—1 gram—dose and home increase in the dose as a strategy that will allow incorporation of peanut into the diet in a developmentally accommodating manner.”

New guidelines from the American Academy of Allergy, Asthma, and Immunology and the American College of Allergy, Asthma, and Immunology are on the way, Lin reveals, adding that she hopes the report will encourage allergists to offer oral food challenges to infants with large skin prick tests who would otherwise be advised to avoid oral food challenges.

“Although risks still exist, our approach allows a wider population of infants to undergo dietary introduction of peanut in a supervised setting, with continued dietary incorporation at home and potentially decreasing the risk of developing peanut allergy in more infants,” Lin says.

Reference

1. Lin A, Uyguygil B, Robbins K, Ackerman O, Sharma H. Low-dose peanut challenges can facilitate infant peanut introduction regardless of skin prick test size. Annals of Allergy, Asthma & Immunology. 2020;125(1):97-99. doi:10.1016/j.anai.2020.03.026