Detection of Salivary Tryptase Levels in Children following Oral Food Challenges.

BACKGROUND: Oral food challenge (OFC) is commonly used to diagnose food allergy. This test is time and resource intensive, and conclusions are not always unequivocal as this relies on the interpretation of symptoms. Therefore, an objective marker would improve the accuracy of the diagnostic workup of food allergy. OBJECTIVES: The aim of this study was to investigate whether tryptase can be detected in saliva of children following OFC. METHOD: Children from 3 to 18 years of age were eligible for inclusion if an OFC for peanut or tree nut had been recommended. Saliva samples were collected prior to the first dose and 5, 10, and 15 min following the last administered dose during OFC. Assay precision, spike-and-recovery, and assessment of lower limit of detection of the tryptase immunoassay were examined before analysis of tryptase in saliva was performed. RESULTS: A total of 30 children were included (median age 8 years, 63.3% male, 53.3% positive OFC outcome). Tryptase was detected in saliva samples. The mean of the change in baseline tryptase value to each saliva collecting time point was significantly different in patients with a positive OFC outcome compared to a negative outcome (p < 0.01). CONCLUSIONS: This study showed that tryptase can be detected in saliva of children following OFC. Increased levels of tryptase compared to baseline were found if the OFC outcome was positive, suggesting that measuring tryptase in saliva may be useful in the diagnosis of food allergy. Further research is needed to evaluate the potential association between tryptase levels and symptoms.

The dilemma of open or double-blind food challenges in diagnosing food allergy in children: Design of the ALDORADO trial.

BACKGROUND: It is of major importance to diagnose food allergy accurately. Current guidelines support the use of oral food challenges to do so. The double-blind placebo-controlled food challenge (DBPCFC) has been regarded as the 'gold standard' for decades. However, DBPCFCs are costly, and time- and resource-intensive procedures. Structural implementation of less demanding open food challenges will only find support if research demonstrates that their outcome is comparable to DBPCFC, yet this has been proven difficult to investigate. METHODS: We performed a literature review to investigate the diagnostic accuracy of oral food challenges and interviewed 19 parents of children with proven or suspected food allergy about the design of a trial to study this. RESULTS: An overview of the dilemma of diagnosing food allergy using oral food challenges, and the methodological issues and parents' opinions to study this. No comparative studies have been performed using the latest guidelines on oral food challenges. CONCLUSIONS: There is an urgent need to investigate the diagnostic accuracy of different oral food challenge protocols. We present the rationale and design of the ALDORADO trial (ALlergy Diagnosed by Open oR DOuble-blind food challenge) that has been set up to investigate whether the outcome of the open food challenge is comparable to DBPCFC.