May 17, 2017

For the past several years, new parents have been told to hold off on feeding potentially allergenic foods like peanut products to their babies until they reached the ages of 1 to 3.

“What we’ve recently realized is that was exactly the wrong advice,” says pediatric allergist Corinne Keet of Johns Hopkins Children’s Center.

The landmark Learning Early About Peanut (LEAP) trial, conducted in the United Kingdom and published two years ago in The New England Journal of Medicine, found that early exposure to peanut protein was associated with a significantly reduced incidence of peanut allergy. By age 5, the prevalence of peanut allergy among those exposed to peanut in infancy was just 3 percent, compared with 17 percent among those not exposed. As a result, groups like the American Academy of Pediatrics now recommend early introduction of peanut in infants at risk of developing allergy.

But questions remain, says Keet, about who needs to be screened for peanut allergy prior to introduction of peanut, how screening should be conducted and how early peanut consumption will proceed outside of a clinical trial. In an observation study supported by the National Institute of Allergy and Infectious Diseases, Keet and colleagues have set out to find answers.

They’re enrolling 400 infants aged 4 to 11 months at potential risk for peanut allergy, identified by the presence of another food allergy, eczema or a parent or sibling with peanut allergy. The investigators will use a blood test and skin prick test to check for allergies in the infants and then introduce them to peanut (usually a powder mixed with baby food) in a monitored setting. If the infants have no allergic reaction, parents will be asked to regularly feed their babies peanut products each week and return for a follow-up visit 18 and 30 months later. Infants that do react to peanut will be referred to allergy care.

“It’s really exciting that we have these new data that we can introduce peanut early and help prevent peanut allergy, but I’m worried that we may not implement it in a way that is practical,” says Keet. “My goal is to provide data to shape guidelines so we can do this in a way that is safe for children but also doesn’t overwhelm our medical system or lead to unnecessary testing and its consequences.”

Why early exposure to peanut could help isn’t yet clear, Keet explains. “One leading hypothesis is that when you experience allergens through an oral route and then the GI tract, that tends to lead to more tolerance than if you experienced the same allergen, like peanut dust, through the skin,” she says.

“About 1 to 2 percent of the population at large has peanut allergy, while even more test positive for it. We’ve done studies of peanut treatment, which are promising, but it would be much better to prevent peanut allergy rather than treat it.”   

For more information, contact 410-502-4198 or earlypeanutstudy@jhmi.edu.