Are peanut oral food challenges still useful? An evaluation of children with suspected peanut allergy, sensitization to Ara h 2 and controlled asthma.

Background: Sensitization to Ara h 2 has been proposed as a promising biological marker for the severity of peanut allergy and may reduce the need for oral food challenges. This study aimed to evaluate whether peanut oral food challenge is still a useful diagnostic tool for children with suspected peanut allergy and an elevated level of Ara h 2-specific IgE. Additionally, we assessed whether well-controlled asthma is an additional risk for severe reactions.

Methods: A retrospective analysis of 107 children with sensitization to Ara h 2-specific IgE (> 0.35 kU/l) undergoing open peanut challenges during 2012-2018 in the Tampere University Hospital Allergy Centre, Finland.

Results: Of the 107 challenges, 82 (77%) were positive. Serum levels of Ara h 2 -sIgE were higher in subjects with a positive challenge than in those who remained negative (median 32.9 (IQR 6.7-99.8) vs. 2.1 (IQR 1.0-4.9) kU/l), p < 0.001) but were not significantly different between subjects with and without anaphylaxis. No correlation was observed between the serum level of Ara h 2-sIgE and reaction severity grading. Well-controlled asthma did not affect the challenge outcome.

Conclusions: Elevated levels of Ara h 2-specific IgE are associated with a positive outcome in peanut challenges but not a reliable predictor of reaction severity. Additionally, well-controlled asthma is not a risk factor for severe reactions in peanut challenges in children with sensitization to Ara h 2.