There is no major difference in symptom severity between open food challenges (OpenFCs) and double-blind, placebo-controlled food challenges (DBPCFCs) for peanut allergy diagnosis, according to recent findings, and this is regarding children and adults.¹

The results of this analysis originated from a study designed to assess the differences between OpenFCs and DBPCFCs, given that the European Academy of Allergy and Clinical Immunology is known to recommend OpenFC for young children, but in adult patients they recommend DBPCFC.²

To compare both forms of testing in the same patients, the investigators began their research and the data was authored by Carsten Bindslev-Jensen, MD, PhD, from the Department of Dermatology and Allergy Centre at the Odense Research Center for Anaphylaxis (ORCA) in Denmark.

“The primary objective of this retrospective study was to compare severity of objective signs and threshold values (cumulative dose of food allergen eliciting a clinical reaction) in children and adults with peanut allergy, challenged either in an open or double- blind, placebo-controlled protocol with strict objective stop criteria applied in both,” Bindslev-Jensen and colleagues wrote.

Background and Findings

The study investigators conducted their research at the Allergy Centre at Odense University Hospital, Denmark, and they aimed at individuals with confirmed peanut allergies through positive food challenges. They excluded those who had negative or inconclusive challenges and they excluded children who were under 6 years old.

Under the circumstances in which one had multiple challenges, each of these challenges was considered individually by the research team. They noted that a food challenge is a standard procedure designed for diagnosing food allergies at the Allergy Centre, and used for the purposes of education for both patients and parents to help manage their anxiety and to establish thresholds.

The investigators explained that over 90% of study participants followed the standard procedure, with several exceptions as a result of refusal by parents or specific severe responses to a single food which was supported by positive skin prick test as well as specific IgE.

The research team instructed trained staff to execute the food challenges using EAACI guidelines, and they noted the use of whole roasted, unsalted peanuts or peanut flour as allergen sources for their participants’ challenges.

The team explained that their DBPCFCs involved masking peanut allergens in a type of chocolate bar or a matrix. Their dosing schemes were based upon prior protocols, and dosing schedule deviations were done by the clinical staff if they deemed it necessary.

The investigators’ food challenges were graded by the Sampson criteria, and their stop criteria were used to stop their challenges if there were occurrences of objective signs of allergic reactions. They gathered data on allergen ingested, challenge outcomes, symptoms, specific IgE levels, gender, and ages, the entirety of which were in the Allergy Centre's clinical database.

Overall, the investigators used a total of 318 positive OpenFCs as well as 86 DBPCFCs, with no distinctions being reported in either severity of symptoms or in threshold values betweenboth types of challenges, even when analyzed across different age groups.

That said, a larger number of children categorized in the double-blind group reported encountering Grade 3 symptoms, and notably only a single patient had a positive reaction during a placebo challenge.

“Our findings advocate for OpenFC being noninferior to DBPCFC, if performed with strict objective stop criteria by trained staff,” they wrote. “Our findings require further studies for validation, preferably with a prospective approach and direct comparison of both chal- lenge types in all patients, as suggested by de Weger et al.”

References

1. ^{Jessen FB, Mortz CG, Eller E, Gudichsen JH, Baekdal EA, Bindslev-Jensen C. A comparison of double-blind, placebo-controlled food challenge and open food challenge [published online ahead of print, 2023 Aug 4]. Allergy. 2023;10.1111/all.15834. doi:10.1111/all.15834.}
2. ^{Muraro A, Werfel T, Hoffmann-Sommergruber K, et al. EAACI food allergy and anaphylaxis guidelines: diagnosis and management of food allergy. Allergy. 2014;69(8):1008-1025.}