New Advice on Peanut Allergies: LEAPing to Conclusions?

            In April of this year, the American Academy of Pediatrics (AAP) recommended systematically feeding peanuts to at-risk (those with eczema, egg allergies, or both) infants as young as 4-6 months to prevent peanut allergy development (Wallis, 2019, August). Up through 2008, it was believed that peanuts should be avoided until a child turned 2 or 3 (Wallis, 2019, August).

The AAP’s advice is based on a 2015 study by the group Learning Early About Peanut Allergy (LEAP) (Du Toit et al., 2015). In the LEAP study, 640 at-risk infants were tested for peanut sensitivity via a skin prick. Children either had no reaction or a discernibly irritated patch of skin, and those with an excessive skin reaction were eliminated from the study (Du Toit et al., 2015). Next, children were randomly divided into one of two treatment categories: one category waited 60 months to be introduced to peanuts (the “avoidance group”), and the second had doses of peanuts incorporated systematically into their diets starting at 4-11 months of age (the “consumption group”) (Du Toit et al., 2015).

            Out of the 530 infants who had no reaction to the skin test at the start of the study, 13.7% of the avoidance group developed a peanut allergy while only 1.9% of the consumption group developed a peanut allergy (Du Toit et al., 2015). Out of the remaining 98 children who tested positive during the initial skin test, 35.3% of the avoidance group still had the allergy while only 10.6% of the consumption group still had the allergy (Du Toit et al., 2015). Both of these statistics had significant p-values, suggesting strong evidence for the ability of early peanut introduction to reduce the chance of or reverse peanut allergy development in high-risk infants (Du Toit et al., 2015). 

            The suspected physiology ongoing in the consumption group is that children develop peanut-specific IgG4 antibodies (known biomarkers of potential immune modulation) (Du Toit et al., 2015). Contrarily, children in the avoidance group developed higher IgE peanut-specific antibodies (known biomarkers of allergic responses) (Du Toit et al., 2015).

            Despite these findings, administering peanuts to younger children should be done with extreme caution. Rabinovitch et al. called out the LEAP study for not including a more diverse subject population (the participants were 70% white) and for not emphasizing the harmful consequences for the 1.9% of the negative skin test/consumption group that did still develop a peanut allergy (Rabinovitch, Shah, & Lanser, 2015). An African American high-risk infant with a negative skin test went into anaphylaxis while being monitored during his first peanut-dosing, but was luckily at the hospital and recovered (Rabinovitch et al., 2015). Regardless of whether this infant’s ethnicity was actually correlated to the anaphylaxis, in the context of justice and non-maleficence researchers should always use diverse groups in studies to effectively assess risks across different populations.

Cited Literature

Du Toit, G., Roberts, G., Sayre, P. H., Bahnson, H. T., Radulovic, S., Santos, A. F., . . . Team, L. S. (2015). Randomized trial of peanut consumption in infants at risk for peanut allergy. N Engl J Med, 372(9), 803-813. doi:10.1056/NEJMoa1414850

Rabinovitch, N., Shah, D., & Lanser, B. J. (2015). Look before you LEAP: Risk of anaphylaxis in high-risk infants with early introduction of peanut. J Allergy Clin Immunol, 136(3), 822. doi:10.1016/j.jaci.2015.07.002

Wallis, C. (2019, August). If you give a baby a peanut. Scientific American, 22.