D1.72 - Assessing potential influencing factors on allergic reaction to the cumulative dose given on an extra day within oral food challenge in food-allergic children

To minimize the false-negative rate, the standard for conducting an oral food challenge (OFC) includes administering the cumulative dose (CD) of the titrated OFC on a separate day. The aim of this study was to analyse potential influencing factors on allergic reaction to the CD in food-allergic children.

We analysed retrospectively electronic charts on double-blind Placebo-controlled food challenges (DBPCFCs) of children with a suspected IgE-mediated food allergy performed between 2016-2022 at the Department of Paediatrics, Goethe University Frankfurt. For inclusion, patients had to undergo a DBPCFC that followed a protocol including a serving of a CD on a separate day if indicated. Possible influencing factors were compared between the group “negative on titrated OFC but positive to CD” versus “positive on titrated OFC”. To assess whether the eliciting dose follows a log-normal distribution, we visually compared the cumulative distribution function of the empirical data set with a simulated one.

Of 966 evaluable DBPCFCs, 401 OFCs in 299 patients were considered positive. Of these, 33 OFCs (8.2%) were considered positive on the CD. Patients reacting to the CD were significantly younger (median age: 3 years (IQR 2;5)) compared to patients reacting to titrated allergen-OFCs (median age: 4 years (IQR 2;6), p=0.03)).

Per allergen tested, reactions to the CD were more frequent in OFCs for wheat (33.3%), raw cow’s milk (17.2%) and hazelnut (11.6%) compared to peanut (6.8%), raw hen’s egg (4.4%) or walnut (2.9%). Gender, atopic comorbidities, previous history of allergen consumption, number and order of OFCs per inpatient stay, and severity of allergic reactions did not differ between groups.

Visualisation of the eliciting dose indicated a normal distribution for peanut-, raw hen’s egg-and walnut-OFCs. For hazelnut-, wheat- or raw cow’s milk-OFCs, more patients than expected reacted to the CD.

Contrary to the hypothesis of a possible desensitization effect during titrated OFCs, the modelled normal distribution for some allergens suggests that, due to exposure to an increased dose at the CD, a certain number of patients are expected to react to the CD. Therefore, to minimize false-negative test results, the CD should continue to be part of the DBPCFC protocol. However, it remains unclear whether giving a higher dose, similar to the CD, on the titrated day could be as effective as administering the CD on a separate day.