Identifying infants at high risk of peanut allergy: The Learning Early About Peanut Allergy (LEAP) screening study
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Published:25th Mar 2020
Background: Peanut allergy (PA) is rare in countries in which peanuts are introduced early into infants� diets. Learning Early About Peanut Allergy (LEAP) is an interventional study aiming to assess whether PA can be prevented by oral tolerance induction. Objective: We sought to characterize a population screened for the risk of PA. Methods: Subjects screened for the LEAP interventional trial comprise the LEAP screening study cohort. Infants were aged 4 to 10 months and passed a prescreening questionnaire. Results: This analysis includes 834 infants (mean age, 7.8 months). They were split into the following: group I, patients with mild eczema and no egg allergy (n = 118); group II, patients with severe eczema, egg allergy, or both but 0-mm peanut skin prick test (SPT) wheal responses (n = 542); group III, patients with severe eczema, egg allergy, or both and 1- to 4-mm peanut wheal responses (n = 98); and group IV, patients with greater than 4-mm peanut wheal responses (n = 76). Unexpectedly, many (17%) in group II had peanut-specific IgE sensitization (?0.35 kU/L); 56% of group III were similarly sensitized. In contrast, none of the patients in group I and 91% of those in group IV had peanut-specific IgE sensitization. Sensitization on skin testing to peanut (SPT response of 1-4 mm vs 0 mm) was associated with egg allergy and severe eczema (odds ratio [OR], 2.31 [95% CI, 1.39-3.86] and 2.47 [95% CI, 1.14-5.34], respectively). Similar associations were observed with specific IgE sensitization. Black race was associated with a significantly higher risk of peanut-specific IgE sensitization (OR, 5.30 [95% CI, 2.85-9.86]). Paradoxically, for a given specific IgE level, black race was protective against cutaneous sensitization (OR, 0.15 [95% CI, 0.04-0.61]). Conclusion: Egg allergy, severe eczema, or both appear to be useful criteria for identifying high-risk infants with an intermediate level of peanut sensitization for entry into a PA prevention study. The relationship between specific IgE level and SPT sensitization needs to be considered within the context of race.