The Benefits of New Guidelines to Prevent Peanut Allergy

Peanut allergy appears to have tripled in prevalence in the United States since 1997 and now affects 1% to 2% of children.(1) The high prevalence, severity, and life-long persistence of peanut allergy have generated intense interest in prevention strategies. Initially, such strategies focused on allergen avoidance, but a key observation, the 10-fold higher rate of peanut allergy among Jewish children in the United Kingdom compared with Israeli children of similar ancestry, suggested an alternative approach.(2) A notable difference between these populations was the almost complete lack of peanut ingestion in the first year of life in the United Kingdom compared with substantial consumption among Israeli infants. Based on this observation, the National Institutes of Health sponsored Learning Early About Peanut Allergy (LEAP) trial randomized 640 infants between 4 and 11 months of age with severe eczema and/or egg allergy to consume or avoid peanut-containing foods until 60 months of age.(3) The study excluded infants with large (>4 mm) positive skin prick tests (SPTs) to peanut, assuming many were already allergic, and stratified the enrolled infants as having no peanut SPT wheal or having one that was 1 to 4 mm in diameter. In the intention-to-treat population with negative SPT (n = 530), the prevalence of peanut allergy at 60 months of age was 13.7% in the avoidance group versus 1.9% in the consumption group (P < .001; 86.1% relative risk reduction), and among those in the SPT positive group (n = 98), the prevalence of peanut allergy was 35.3% in the avoidance group and 10.6% in the consumption group (P = .004; 70% relative risk reduction).