2018 Section 5 - Rhinology and Allergic Disorders

However, as more data from observational cohort studies emerged, the American Academy of Pediatrics reversed this guidance in 2008 (as did the American Academy of Allergy Asthma and Immunology in 2013) and made a passive recommendation that introduction of solid foods not be delayed past 4–6 months of life given “serious questions about the benefit of delaying the introduction of solid foods that are thought to be highly allergic” but not further specifying what was an appropriate timing to introduce such foods, peanut included. 9 Recently, two studies noted poor adherence with these recommendations. The Infant Feeding Prac- tices II study noted that 0.5% of U.S. infants have peanut introduced by 5 months and 20% by 12 months; and nested data from a 2014 birth cohort study noted only 7% of infants had solid-food introduction by 4 months and 13% by 6 months, with peanut intro- duction occurring, on average, at 20.2 months. 10,11 Thus, although there is a paucity of data that monitors adherence as an outcome, analysis of these data would indicate sluggish uptake of the 2008 guidelines. THE LEARNING EARLY ABOUT PEANUT ALLERGY STUDY AND LEVEL I EVIDENCE OF PRIMARY AND SECONDARY PEANUT ALLERGY PREVENTION In 2008, Du Toit et al. published the results of a provocative observational study of Ashkenazi Jewish children who lived in London, England, and Tel Aviv, Israel. In this study, surveys were used to determine the prevalence of peanut allergy in two cohorts of 5000 children in each city. The prevalence of peanut allergy in London, where, at the time, the standard recommendation was peanut avoidance until age 3 years, was 10-fold higher than in Israel, where peanut was introduced in the first year of life. The only sig- nificant factor noted to explain the difference in the rates of peanut allergy was the timing of introduc- tion. 12 Although this study could not imply causality that early introduction was associated with a lower prevalence of peanut allergy, it did generate the hy- pothesis behind the Learning Early About Peanut Al- lergy (LEAP) randomized controlled study. In the LEAP study, 640 infants, ages 4–11 months, with either moderate-to-severe eczema, egg allergy, or both were randomized to early peanut introduction at enrollment versus deliberate delayed introduction until the age of 5 years. The participants were skin tested at study entry, with those having peanut skin prick tests 4 mm excluded due to a high likelihood of preexisting peanut allergy. The participants were stratified by skin prick test size (0 mm versus 1–4 mm) and then ran- domized to either early versus delayed peanut intro- duction. All early peanut introductions were initially done as an open challenge under medical supervision.

The study subjects were then followed up through age 5 years, when both groups underwent supervised open peanut challenge. 13 Overall, peanut allergy developed in 3.2% of the early introduction group compared with 17.2% in the avoidance group ( p 0.001; absolute risk reduction [ARR], 14; number needed to treat, 7.1). However, the differences were more pronounced within the groups stratified by skin testing. Within the group with nega- tive skin tests, 1.9% in the early introduction group versus 13.7% in the avoidance group developed peanut allergy ( p 0.001; ARR, 11.8%; number needed to treat, 8.4). Within the group with positive skin test results, 10.6% in the early introduction group versus 35.3% in the avoidance group developed peanut allergy ( p 0.001; ARR, 24.8; number needed to treat, 4), which demonstrated that there was heterogeneity of the treat- ment effect. A subsequent study of these children, ages 5–6 years, in which all the participants avoided peanut for a year, revealed three new cases of peanut allergy developed in each group, a nonsignificant difference. No fatalities occurred, and no significant differences between the groups in the rate of adverse events were observed. The trial, furthermore, demonstrated that oral food challenge of infants was both safe and feasi- ble. Nutritional assessment of these infants noted no significant differences in the duration of breast-feed- ing between the groups, micronutrient intake, growth parameters, or percentage of calories from protein. Interestingly, the early introduction group was noted to have significantly lower consumption of chips and/or salty snacks, high-fiber bread, juices, and condiments. 13,14 CHANGES TO THE INFANT FEEDING POLICY: THE NATIONAL INSTITUTES OF ALLERGY AND INFECTIOUS DISEASES SPONSORED PEANUT ALLERGY PREVENTION GUIDELINES The LEAP trial provided level I evidence that peanut can be introduced in children at high risk (defined as having either severe eczema and/or egg allergy) be- tween 4–11 months of life. 13 The trial was enormously successful and demonstrates the tremendous potential for both primary and secondary peanut allergy preven- tion. Based on the LEAP study results, there has been strong consensus that a more-specific recommendation could be made as to when to introduce peanut and strengthen the current guidance to not delay solid-food introduction past 4–6 months of life. 15 In the summer of 2015, a multinational group of Allergy, Pediatric, and Dermatology societies issued a Consensus Com- munication, which echoes the sentiment that the result of the LEAP study indicated that early peanut intro- duction in such infants at high risk is safe and should be encouraged, which follows the protocol in the LEAP

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