Is age a critical factor for the diagnosis of peanut allergy in children?

Background Peanut allergy (PA) is a significant health concern. Some children with PA may present with a relatively high reaction threshold. However, even in this group the chances of spontaneous resolution are low and there is significant impairment in the quality of life. Newer data suggest that treatment protocols in this group are safer and easier to implement. Objective This study aims to identify clinical factors influencing reaction threshold and challenge outcomes in PA children, assisting physicians to estimate the allergic threshold and improving the chances to diagnose children with high threshold PA. Methods A retrospective study, collecting and analyzing data of challenge-proven PA children under 12 years of age, from our pediatric food allergy center, where all children with suspected PA are offered a diagnostic challenge. The data included demographics, medical history, skin test and oral food challenge results. Results A total of 194 children under 12 years of age (mean 43 months, 95% CI 38.9–47.1) with challenge-proven PA were enrolled in the study. Children with low threshold PA (threshold less than 100 mg) were older (52.5 months % vs 33.6 months, p < 0.001) and had larger wheal size during skin prick tests (11.2 mm vs 8.3 mm, p < 0.001). In girls an additional predictor of low threshold was a previous systemic/anaphylactic reaction ( p < 0.001). Using exploratory machine-driven decision tree analysis, an age of 18 months or younger yielded a negative predictive value of over 94% for developing respiratory reactions and a markedly lower incidence of anaphylaxis compared with older children. Conclusion Since an oral food challenge is the gold standard for the diagnosis of PA, performing a diagnostic challenge at a young age, may optimize the chance to diagnose PA with a relatively high threshold, increasing the safety and outcomes of potential interventions. Therefore, the early referral of young patients for a diagnostic workup is strongly recommended.