Reactions to peanut at first introduction in infancy are associated with age ≥8 months and severity of eczema

Background: Previous studies have shown the efficacy of the early introduction of peanut to prevent peanut allergy. Due to the exclusion of infants with sensitization to peanut, it remains unclear what the optimal timing of introduction is. Methods: The PeanutNL study was performed in 6 pediatric allergology centers in the Netherlands. Infants referred for the clinical early introduction of peanut to prevent peanut allergy underwent skin prick tests for peanut and an oral peanut challenge at a median age of 6 months. Results: One hundred sixty two of 707 infants (23%) who had never eaten peanut before were sensitized to peanut, of which 80 (49%) had wheals of >4 mm. Sixty seven of 707 infants (9.5%) had a positive oral challenge to peanut at first introduction. Multivariate analysis revealed that age (p <.001) and SCORAD eczema severity scores (p =.001) were significant risk factors. Introduction of peanut at ≥8 months in infants with moderate and severe eczema resulted in an increased risk (odds ratio 5.24 (p =.013) and 3.61 (p =.019), respectively) of having reactions to peanut as compared to introduction before 8 months. A family history of peanut allergy and previous reactions to egg were not identified as independent risk factors. Conclusion: These results suggest that peanut should be introduced before the age of 8 months to reduce the risk of reactions at first exposure in infants with moderate and severe eczema. Furthermore, since children with severe eczema have the highest risk of reactions, the clinical introduction of peanut should be considered, at the latest at the age of 7 months.