Ask the expert: Is it possible to prevent peanut allergy?

I have seen so many of my friends’ children diagnosed with severe food allergies. Is there anything I can do to stop my baby from having a peanut allergy?


Panicked about peanuts

John Lee, MD, clinical director, Boston Children’s Hospital Food Allergy Program
John Lee, MD, clinical director, Boston Children’s Hospital Food Allergy Program

Food allergies are on the rise. They are more prevalent than ever before. It is estimated that one in 13 school kids have a life-threatening food allergy. Although some food allergies can be outgrown, peanut allergies tend to be lifelong.

In the hope of preventing allergies, doctors used to recommend avoiding foods that are more commonly allergenic—like peanuts, tree nut, fish and egg—in the first years of life. However, since this did not stem the rise in food allergies, our thinking has changed toward earlier introduction of foods to induce tolerance. For the past several years, the American Academy of Pediatrics has recommended introducing these foods in the first year of life for those without a history of allergies.

A recent study published in The New England Journal of Medicine looked at this closely. It evaluated the effect of early and deliberate introduction of peanuts in infants on the development of food allergies. The results of this study were more successful than anyone had ever thought they would be, and are changing how we approach prevention of food allergies.

The concept behind the study is based on a simple observation about a hugely popular snack food in Israel. Bamba, a peanut-based snack, is offered to many infants at a very young age.

With this early exposure to peanuts, some may have expected rates of peanut allergies in Israel to be high. Quite the opposite. Frequency of peanut allergies is dramatically lower compared to the level in Western countries. One study observed that the rates of allergies are 10 times lower compared to a control group of Jewish children in the United Kingdom.

Based on this idea of early introduction of peanuts, this landmark study looked at infants 4 to 11 months of age who had either atopic dermatitis or an allergy to egg. These infants, who were thought to be at-risk for peanut allergy, were screened for peanut allergies by skin testing. If testing was high positive then peanut introduction was considered too risky, and it was advised to strictly avoid peanuts.

The remaining infants who tested negative or low positive were randomized to either avoid peanuts or to eat peanuts at least three times per week. To ensure safety, infants who were to eat peanuts underwent a medically supervised challenge with their first exposure. At the age of five, children in these two groups were given peanuts to determine whether or not they have developed a true peanut allergy.

Here are the results. For infants who tested negative on the initial screen, in the group of children who were avoiding peanuts, 13.7 percent developed a peanut allergy, whereas only 1.9 percent developed a peanut allergy if they were instructed to regularly eat peanuts. For the infants who tested low positive to peanuts initially, 35.3 percent of the peanut-avoiding children developed a peanut allergy compared to 10.6 percent of those recommended to eat peanuts.

These results are astounding. From this simple intervention, peanut allergies were reduced by 70 to 86 percent in children who were at an increased risk. It is very important to note that this study looked at only those who were thought to be at increased risk (e.g., moderate-to-severe eczema or egg allergies) and those with high allergy skin test results were advised to avoid peanuts.

So how can the results of these studies help you and your baby? The Food Allergy Program at Boston Children’s has set up a screening program for at-risk infants such as those who already have eczema or food allergies. We can perform skin testing for peanuts and recommend whether or not to introduce peanuts. If there is a concern for possible reactions, we will monitor the first exposure to peanuts.

If you are interested in screening your child for peanut allergies, please call us at 617-355-6117 and ask for an Infant Peanut Allergy Evaluation.