TOPLINE

Among infants younger than 18 months with a prior peanut reaction and evidence of sensitization, more than a third had a negative challenge, enabling immediate delabeling and regular peanut consumption. Despite the associated risk for anaphylaxis, the challenge was well managed.

METHODOLOGY

• Researchers conducted a retrospective chart review at 10 hospitals across Australia between April 2024 and October 2025 to assess whether an oral food challenge performed before starting peanut oral immunotherapy (OIT) could confirm allergy and safely guide the starting dose within the country's standardized national program.
• Eligible infants had a grade 1 or 2 allergic reaction to peanuts before 12 months of age and evidence of sensitization (a wheal diameter of ≥ 3 mm on a peanut skin prick test or peanut- or Ara h 2-specific immunoglobulin E levels ≥ 0.35 kUA/L). They were younger than 18 months at the time of the challenge.
• Of 1275 infants assessed, 778 (median age at the time of the challenge, 13 months; 54.5% boys) underwent a threshold oral food challenge, receiving seven escalating doses of peanut protein (15 mg-1300 mg) at 15-minute intervals.
• Researchers assessed the proportion of negative challenges, the anaphylaxis rate, and whether the challenge-determined starting dose for OIT was tolerated.
• They also examined whether the skin prick test wheal size and Ara h 2 blood levels predicted the challenge outcome.

TAKEAWAY

• Overall, 65.2% of the oral food challenges were positive, with a median eliciting dose of 120 mg of peanut protein. Anaphylaxis occurred in 7.8% of all challenges, 12.0% of the positive ones.
• Among 394 infants who began immunotherapy using the challenge-determined starting dose, 97.5% (384 infants) tolerated the dose at the first updosing visit; one infant could not tolerate a 3-mg dose and was withdrawn from the program because a lower dose could not be given reliably.
• Skin prick test wheals were larger in infants who reacted than in those who did not (median, 7 mm vs 5 mm), and Ara h 2-specific immunoglobulin E levels were higher (2.1 kUA/L vs 0.3 kUA/L; P < .001 for both). The tests did not predict the dose at which infants reacted or the severity of the reaction.
• Infants with eczema or other food allergies were more likely to react during the challenge (P < .05 for both). Sex, the hospital site, language used at home, age at the first reaction, age at the challenge, and the severity of the first reaction were not associated with a positive challenge result.

IN PRACTICE

"We strongly recommend considering this approach for diagnosis of peanut allergy in infants regardless of whether OIT or an allergen avoidance strategy is being pursued," the authors wrote.

"Accurately confirming allergy via OFC [oral food challenge] in infants can reduce the patient, family and societal burden of allergy through misdiagnosis and, prior to commencement of OIT, can additionally help avoid unnecessary treatment," they added.

SOURCE

Kirsten P. Perrett, MBBS, PhD, with the Murdoch Children's Research Institute, Parkville, Australia, was the corresponding author of the study, which was published online on September 17 in The Journal of Allergy and Clinical Immunology: In Practice.

LIMITATIONS

This was a retrospective analysis of medical records collected across multiple hospital sites, and the proportion of eligible infants who underwent the challenge differed across hospitals. Some sites prioritized infants who were less likely to react or whose families wanted to start OIT. Eczema was recorded only as present or absent rather than graded by severity; therefore, its specific effect on challenge results could not be fully examined.

DISCLOSURES

The study was supported by the National Allergy Centre of Excellence, backed by federal funding from the Australian government, and by philanthropic support to the Murdoch Children's Research Institute. One author reported receiving research grants and consultant fees from several pharmaceutical companies, with payments made to their institution.

This article was created using several editorial tools, including AI, as part of the process. Human editors reviewed this content before publication.