Letter of response to Greenhawt et al. ‘LEAPing Through the Looking Glass: Secondary Analysis of the Effect of Skin Test Size and Age of Introduction on Peanut Tolerance after Early Peanut Introduction’

Food allergy is an important public health problem because it affects children and adults, can be severe and even life-threatening, and may be increasing in prevalence. Beginning in 2008, the National Institute of Allergy and Infectious Diseases, working with other organizations and advocacy groups, led the development of the first clinical guidelines for the diagnosis and management of food allergy. A recent landmark clinical trial and other emerging data suggest that peanut allergy can be prevented through introduction of peanut-containing foods beginning in infancy.

Background In the Learning Early About Peanut Allergy (LEAP) study, early peanut introduction in high-risk 4-11 month olds was associated with a significantly decreased risk of developing peanut allergy. However, the influences of key baseline high-risk factors on peanut tolerance are poorly understood. Methods Secondary analysis was conducted on the publically available LEAP dataset, exploring relationships between peanut tolerance, baseline peanut/egg sensitization, eczema severity/duration, age of introduction, gender, and race. Results A multiple logistic regression model predicting odds of successful oral food challenge (OFC) at 60 months noted higher odds with early introduction (OR 9.2, P<0.001, 95%CI 4.2-20.3), white race (OR 2.1, p=0.04, 95%CI 1.1-3.9), and advancing age (OR 4.8, P=0.04, 95%CI 1.1-20.8). Odds of peanut tolerance were lower with increasing peanut wheal size (OR 0.58, P<0.001, 95%CI 0.46-0.74), increased baseline SCORAD score (OR 0.98, p=0.04, 95%CI 0.97-1), and increased kU A /L of egg serum IgE (sIgE) (OR 0.99, p=0.04, 95%CI 0.98-1). The probability of peanut tolerance in the early introduction group was 83% vs. 43% in the avoidance group with SPT wheal of less than 4mm. The probability of a successful OFC was significantly higher with peanut introduction between 6-11 months than at 4-6 months. Increasing eczema severity had limited impact on the probability of peanut tolerance in the early introduction arm. Conclusion Increasing peanut wheal size predicted peanut tolerance only in the avoidance arm. Peanut introduction between 6-11 months of age was associated with the highest rates of peanut tolerance, questioning the “urgency” of introduction before 6 months.