Comparison of Double-Blind and Open Food Challenges for the Diagnosis of Food Allergy in Childhood: The ALDORADO Study

Background: Double-blind placebo-controlled food challenge (DBPCFC) is widely regarded as the "gold standard" to diagnose food allergy. Maximum efforts are made to reduce bias, yet DBPCFCs are costly, time-, and resource-intensive. Less demanding open food challenges are increasingly used in clinical practice. However, recommendations regarding the use of these challenges are based on low certainty of evidence, and no comparative studies have been performed using the most recent international food challenge guidelines. We hypothesised that the open food challenge is non-inferior to DBPCFC in children suspected of allergy to cashew nuts, hazelnuts or peanuts.

Methods: A total of 63 children, aged 4 years and older, were included if referred for suspected IgE-mediated allergy to cashew nut, hazelnut, or peanut. All study participants underwent DBPCFC first, followed by an open food challenge for the same food. Challenge outcomes were assessed by predefined criteria into positive, negative, or inconclusive.

Results: DBPCFC and open food challenge outcomes were the same for 36/41 (87.8%) patients. Sensitivity and specificity of the open food challenge were 0.91 (95% CI 0.79, 1.03) and 0.83 (95% CI 0.63, 1.01), respectively, with an AUC value of 0.87. Eliciting and stop doses were not significantly different between both food challenges.

Conclusion: The Diagnostic accuracy of open food challenge is non-inferior to that of DBPCFC. This finding implies less demanding open food challenges can be implemented for children from the age of 4 years suspected to be cashew nut, hazelnut, or peanut allergic. Further research is necessary to validate our findings and to investigate the diagnostic accuracy for other major food allergens.