Reactions to Peanut during a Double-Blind Placebo Controlled Food Challenge (DBPCFC) for Enrolment in a Randomized Trial

Rationale: Few studies have comprehensively examined reaction characteristics in a large cohort. We describe symptoms and eliciting doses during DBPCFC in children with peanut allergy. Predictors of cumulative reaction-eliciting dose and severity were also examined.

Methods: Children underwent a DBPCFC (4950mg peanut protein). Demographics, peanut sIgE, peanut skin prick test (SPT) and reaction characteristics were recorded. Associations between variables were investigated by correlation, linear and logistic regression analyses.

Results: 112 children completed DBPCFC; 7 did not react, 103 reacted to peanut but not placebo, and 2 reacted to both peanut and placebo. The median cumulative reaction-eliciting dose was 1200mg (IQR 560–2450). 23.4% reacted to ≤240 mg and 51.4% to ≥1200mg. Abdominal pain (68%) and vomiting (59.2%) were the most frequent symptoms. Anaphylaxis occurred in 21.4%. There was no association between reaction-eliciting dose and reaction severity. Peanut sIgE and SPT were negatively correlated to reaction-eliciting dose (p<0.001) but sIgE was the only predictor on regression analysis (p0.002). Peanut sIgE and SPT were not associated with and did not predict reaction severity.

Conclusions: Reaction-eliciting dose varied widely in this cohort of peanut allergic children, with the majority (76.6%) reacting to ≥560mg peanut protein. Severity of reaction was not related to dose at reaction and is difficult to predict. DPBCFC were equivocal or negative in 8.7% of children, supporting inclusion of DBPCFC at study entry to confirm eligibility in food immunotherapy trials.