A landmark Australian study has found that roughly one in three infants previously suspected of having a peanut allergy showed no reaction when given a controlled oral food challenge, raising significant questions about how early childhood peanut allergies are diagnosed and managed.

The findings, which emerged from a nationwide immunotherapy program, suggest that hundreds of families may have been adjusting their daily lives and dietary habits based on a diagnosis that does not hold up under clinical testing conditions.

What the Peanut Allergy Study Found

The research drew on data from the national ADAPT Peanut Oral Immunotherapy Program, launched in 2024 by the National Allergy Centre of Excellence and hosted at the Murdoch Children's Research Institute. The program was originally designed to improve tolerance to peanuts in allergic infants, but it began with oral food challenge testing to establish each child's level of sensitivity.

Of 778 infants enrolled, 35 per cent showed no reaction at all during the oral test, meaning their suspected peanut allergy diagnosis was effectively removed. Senior clinician Dr Tim Brettig said the scale of that result was unexpected.

"We expected some to tolerate peanut at a food challenge, but the rate's much higher than we would have thought," he said. "To get such a large number of infants not react and therefore not even need treatment because of an allergy was really exciting."

Despite the encouraging numbers, the testing process carried genuine risk. During the initial oral challenges, 12 per cent of infants had an anaphylactic reaction requiring treatment from medical staff on site. Dr Brettig was clear that this type of testing must be conducted in a controlled clinical environment and should not be attempted at home.

"It needs to be done in a controlled and safe way," he said.

One Family's Relief After Diagnosis Reversed

Among the families affected was that of one-year-old Arthur Cameron, whose suspected peanut allergy was removed following the oral food challenge. Arthur had first shown signs of a reaction at around five months of age after being given peanut butter, breaking out in hives and becoming red in the face. Subsequent skin and blood tests indicated a high risk of further reactions.

Yet when Arthur underwent the oral food challenge as part of the program, he tolerated peanut without any reaction.

His mother Leah described the diagnosis as an added layer of stress for a first-time parent. "Being a first-time new mum there's enough kind of stress and anxiety around having a child," she said. "And then finding out he had this peanut allergy, it certainly made us worry a bit how we'll manage this through his life."

She said the family had been carefully checking food labels and rethinking meals, including giving up dishes like satay chicken. The reversal of Arthur's diagnosis came as a welcome shock. "We were very surprised, but very ecstatic," Leah said.

Implications for How Peanut Allergies Are Diagnosed

The study's results point to a broader question about how peanut allergies are identified and confirmed in infants. Skin prick and blood tests are commonly used to assess allergy risk, but the findings suggest these alone may not give a complete picture. Without oral food challenge testing, children like Arthur would likely have continued avoiding peanuts indefinitely, potentially missing out on a food that poses no real threat to them.

Dr Brettig acknowledged that researchers are not yet sure why some infants who initially appeared sensitive to peanuts no longer react by the time formal testing takes place. The study adds to a growing body of research suggesting that some medical diagnoses may be more prevalent on paper than in practice, underlining the value of rigorous clinical confirmation before lifelong management plans are put in place.

The findings are expected to prompt fresh discussion among clinicians about when and how oral food challenges should be offered to infants flagged as high-risk for peanut allergy, with researchers suggesting the approach may warrant broader consideration than it currently receives.