Study Finds One in Three Infants Previously Diagnosed with Peanut Allergy Tolerate Peanut in Challenge
Australian researchers report that 35% of infants under 18 months previously diagnosed with peanut allergy showed no reaction during supervised oral food challenges, suggesting the need for confirmatory testing before long-term treatment.
More than a third of infants who had been diagnosed with a peanut allergy were able to tolerate peanut during a supervised oral food challenge, according to a national study conducted by the Murdoch Children’s Research Institute and the National Allergy Centre of Excellence. The findings, published in The Journal of Allergy and Clinical Immunology: In Practice, highlight the importance of confirming an allergy before committing children to long-term avoidance or immunotherapy.
The study enrolled 1,275 infants under 18 months from ten paediatric hospitals across Australia between April 2024 and October 2025. All participants had previously received a peanut allergy diagnosis based on clinical history and initial testing. During the challenge, each child was given incremental doses of peanut flour over a 90-minute period, up to a maximum of one teaspoon (approximately 2,500 mg of peanut protein). Children who showed no reaction were observed for two additional hours before being considered tolerant.
“We didn’t have exact [expected] numbers, but definitely nowhere near a third in itself,” said Dr Tim Brettig, senior research clinician at MCRI, noting that the results were surprising to the research team.
Of the original cohort, 778 infants proceeded to the oral food challenge; the remainder did not, primarily because families declined participation. Among those challenged, 35% showed no allergic reaction, while 65% did, including 12% who experienced anaphylaxis. Almost all infants who reacted were started on peanut oral immunotherapy, with 97.5% successfully initiating treatment at doses guided by the challenge outcomes.
“There is a lot of anxiety around food,” Dr Brettig said, adding that the findings may encourage more families to consider re-evaluation of a peanut allergy diagnosis.
The researchers propose that infancy may represent a window during which some peanut allergies are transient or still developing, though the exact mechanisms remain unclear. They recommend that general practitioners and maternal-child health nurses refer children with suspected peanut allergy to specialist centres for comprehensive assessment rather than accepting an initial diagnosis without further testing.
“Our takeaway is that we should be referring patients to a specialist centre for further assessment, rather than just accepting a diagnosis,” Dr Brettig said.
The study underscores the potential for de-labeling peanut allergy in a substantial minority of young children, which could reduce unnecessary dietary restrictions and long-term treatment burdens.