Infants at high risk for peanut allergy should start a peanut-based diet by age 4-11 months, experts from the American Academy of Pediatrics and nine other medical groups advised in the September issue of Pediatrics.*
The consensus communication upends traditional views about preventing childhood peanut allergy and highlights the landmark LEAP study in which high-risk infants fed peanut-based foods had about an 80% lower risk of developing peanut allergy, compared with those fed a peanut-free diet.
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“Early intervention will prevent peanut allergy, and the pediatrician’s involvement is absolutely essential to the success of this approach,” said Dr. Hugh Sampson, who contributed to the guidance and is at the Icahn School of Medicine at Mount Sinai, New York. “Without very early evaluation and implementation, we won’t change anything.”
LEAP investigators defined “high risk” for peanut allergy as severe eczema with or without egg allergy, “but many other infants are likely at risk, and thus would benefit from early peanut introduction,” added Dr. David Fleischer, who also contributed to the guidance and is at the University of Colorado at Denver, Aurora. “Many feel that given the potential benefit, all infants, regardless of risk level, should have peanut introduced early into the diet,” he said.
Peanut allergy affects more than 2% of American children and is about twice as prevalent in Western countries as it was a decade ago. It’s not clear why rates have increased, but pediatricians can help stem the rising tide, Dr. Sampson said. “When a pediatrician suspects a ‘high-risk’ baby, he or she needs to explain to parents the risks involved in their baby developing peanut allergy, and the benefits of early evaluation and introduction. Once peanut allergy is established, the vast majority of young children will retain the allergy for life.”
Because “high-risk” children might already be allergic to peanuts, they could benefit from evaluation by an allergist, according to the consensus communication (Pediatrics 2015;136[3]:601-4). Expert consultation might also benefit those who feel reluctant to introduce peanuts for other reasons, Dr. Fleischer said.
Dr. Sampson recommends peanut-based skin prick testing for high-risk infants aged 4-8 months. Patients with a negative result should receive 2 grams of peanut protein three times a week for the next 3 years. Those who are mildly sensitive (wheal diameter less than 4 mm) should undergo a peanut challenge observed by an experienced physician. Infants who do not react can start the peanut-based diet.
The LEAP study randomized 640 high-risk infants to either avoid peanuts or consume at least 6 grams per week of the allergen in foods such as smooth peanut butter mixed with mashed fruit, peanut soup, and ground peanuts in other foods. Five-year-olds in the peanut group had significantly lower rates of peanut allergy, regardless of whether their skin prick test had been positive at baseline (N. Engl. J. Med. 2015;372[9]:803-13). While the consensus communication provides interim guidance, a panel sponsored by the National Institute of Allergy and Infectious Diseases is reviewing food allergy data in preparation for updating its guidelines, Dr. Sampson noted. “Several major questions remain,” he said. “Do we need to give such large amounts of peanut to induce tolerance? Is it necessary to give this amount of peanut for such an extended period? What happens if parents don’t give peanut to their infants on a regular basis, as done in the LEAP trial? Could this put them at higher risk? And will this approach apply to other foods?”
Another key knowledge gap is whether the results from one single-center study can be applied elsewhere, said Dr. Fleischer. “We do not know the effects of early peanut introduction in other risk populations.”
Authors of the consensus communication reported no funding sources or conflicts of interest.
*Correction, 8/31/2015: An earlier version of this article misstated the journal in which the study was published.