One in three infants diagnosed with peanut allergy may not have it

If your child was diagnosed with a peanut allergy in their first year of life, there is an important new finding from Australian researchers that is worth knowing about — and worth raising with your GP.

A large national study published in the Journal of Allergy and Clinical Immunology: In Practice found that approximately 35% of infants diagnosed with peanut allergy before 12 months did not react when given peanut under careful supervised challenge conditions. That is roughly one in three diagnoses that could potentially be lifted.

The study was conducted by researchers at the Murdoch Children’s Research Institute and the National Allergy Centre of Excellence. It enrolled 1,275 infants under 18 months — median age 13 months — assessed at 10 paediatric hospitals across Australia between April 2024 and October 2025. All had been diagnosed with peanut allergy before 12 months based on clinical history and initial allergy testing. Of the 1,275 infants, 778 proceeded to an oral food challenge.

The challenge protocol involved increasing doses of peanut flour given under supervision over 90 minutes, with a maximum single dose of one teaspoon of peanut protein and a two-hour post-challenge observation period for delayed reactions.

What this means — and what it does not

Lead researcher Dr Tim Brettig said the team was surprised by how many infants passed the challenge. This is good news for a lot of families. But it is emphatically not an invitation to try peanut at home.

The flip side is real: 65% of infants in the cohort still reacted, and 12% of those who reacted had anaphylaxis. An oral food challenge is a clinical procedure performed in a facility equipped to manage severe allergic reactions — not a home experiment.

Brettig’s team also noted they cannot yet explain why some infants’ allergies appear to resolve. One working hypothesis is that early infancy may represent a window in which peanut allergy is more transient, or in which the immune system is more amenable to intervention. Research into this window is ongoing.

What the study does establish is a clear practice point: the original diagnosis — made in the first 12 months based on history and testing — may not be the whole story. The recommendation from researchers is to confirm a peanut allergy diagnosis before committing a child to long-term immunotherapy or lifelong peanut avoidance.

Why families often don’t get a challenge

For many families who went through the anxiety of an infant allergic reaction and the relief of a diagnosis, the idea of a supervised challenge can feel counterintuitive — why expose your child to the thing that caused the reaction? Brettig acknowledged this directly: families often carry high anxiety about repeat exposure.

There is also a practical access question. Not all families live near a paediatric allergy centre equipped to perform challenges safely, and referral pathways vary by state. GP awareness is part of the equation here — the researchers noted that GPs and maternal child health nurses do much of the initial work with these families, and their knowledge of the new data matters.

Of the 496 infants in this study who did not proceed to challenge, most did not because families declined. That proportion may shift as these findings become more widely known.

Two sides of the finding

There is a natural tension in this result. For the 35% whose allergy diagnosis could be revised, the upside is significant: not carrying an EpiPen for life, not navigating school canteens and birthday parties with the same level of vigilance, not building a child’s understanding of their body around a diagnosis that may not be accurate.

For the 65% who do still react — and especially the families of children who had anaphylaxis during challenge — the message is different. A diagnosis confirmed by challenge carries more weight than one that was never tested. And for infants who start peanut oral immunotherapy on the basis of a confirmed challenge result, the researchers found that 97.5% of those who reacted were able to begin treatment at a dose guided by their challenge results — meaning the challenge itself provided clinically useful information either way.

2 cents

About one in 30 Australian children has a peanut allergy. The diagnostic window for this study — infants diagnosed before 12 months — is a specific subset. But it is a clinically important one, because early diagnosis often precedes the opportunity for supervised challenge review.

If you have a child with a peanut allergy diagnosis made in their first year, ask your GP whether a referral to a paediatric allergist for review is appropriate. Depending on your child’s history — the original reaction, test results, age now — a supervised challenge may or may not be indicated. That is a clinical judgement, not something to pursue independently.

What this study does clearly is normalise the question. Asking “do we still need this diagnosis?” is now supported by one of the largest Australian multicentre datasets on the topic. It is a reasonable question, and your GP can help answer it.

Verdict: yes — a practice-relevant finding from a large Australian multicentre study that GPs and families with early-diagnosed peanut allergy should know about.

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Sources cited

1. One in three babies may shed peanut allergy diagnosis — newsGP, 5 November 2026
2. Study finds one third of infants diagnosed with peanut allergy can eat nuts — ABC News, 5 November 2026
3. Murdoch Children’s Research Institute — allergy and immune disorders research