When to Introduce Peanut and Egg: What the Guidelines Actually Say Now

For most of the 2000s, the standard advice on peanut was to wait. Hold off past the first birthday, longer still if there was a family history of allergy, on the theory that an infant's immune system needed time before meeting a food that could trigger a severe reaction. The advice was reasonable-sounding and, it turned out, backward. A randomized trial published in 2015 found the opposite: in infants already at high risk of peanut allergy, avoiding peanut for the first several years produced more allergy, not less. Guidance from the National Institute of Allergy and Infectious Diseases (NIAID) and the American Academy of Pediatrics (AAP) has since reversed course entirely, and the recommendation now is to introduce peanut and other major allergens early, not late.

This is the part of starting solids that carries the most consequence and the most confusion, because the right move depends on a specific piece of information most parents do not have on hand: whether their baby is low, moderate or high risk for peanut allergy, which changes both the timing and whether testing comes first.

The trial that reversed the advice

The Learning Early About Peanut Allergy (LEAP) study enrolled infants between four and eleven months old who were already at high risk of developing peanut allergy, defined as having severe eczema, egg allergy, or both. Half were randomly assigned to eat peanut-containing food regularly through age five. The other half avoided peanut entirely, following the older standard advice. By age five, 17% of the avoidance group had developed peanut allergy, compared with 3% of the group that ate peanut regularly, a relative reduction of more than 80% in the children who consumed it early and kept consuming it. The trial was designed and led by researchers at King's College London through the Immune Tolerance Network and published in the New England Journal of Medicine in 2015.

That is a large effect for a single dietary change, and it is specific to a high-risk population that was already going to be watched closely for allergy. But the finding was consistent enough that it reshaped guidance for every risk tier, not just the highest one.

What the guidelines say now, by risk level

NIAID issued addendum guidelines in 2017 building directly on the LEAP results, and the AAP's own consumer guidance follows the same three-tier structure.

Low risk: no eczema, no existing food allergy. These infants can have peanut-containing foods introduced at home, in an age-appropriate form, around six months and alongside other solid foods. No testing is recommended first. This describes most babies.

Moderate risk: mild to moderate eczema. Peanut can still be introduced at home, generally around six months, without a mandatory test beforehand. The guidance leaves some room for family preference and for a pediatrician's judgment on the individual case, but a supervised setting is not a requirement at this tier.

High risk: severe eczema (the kind requiring prescription treatment), an existing egg allergy, or both. This is the group the LEAP trial actually studied, and it is the only tier where NIAID recommends testing before introduction. A peanut-specific IgE blood test or a skin-prick test should be done first, generally in consultation with a pediatrician or allergist, before peanut goes anywhere near the baby's mouth. If testing shows a peanut-specific IgE level of 0.35 kUA per liter or higher, or a skin-prick wheal of 3 to 7 millimeters or more, the recommendation moves to a supervised feeding in a medical office or a referral for an allergist-supervised oral food challenge, rather than a first try at the kitchen table. Lower results than that carry a low estimated risk of reaction, and introduction can proceed at home.

For infants in this high-risk group, the guidance is also specific about timing: ideally introduced at four to six months, earlier than the general six-month window, precisely because the protective effect in the trial came from early and sustained exposure rather than a single taste.

How to actually introduce it

Whole peanuts and whole tree nuts are a choking hazard at any age this guide covers and stay off the table regardless of allergy risk. That restriction has nothing to do with allergy and everything to do with size and firmness. What the guidance means by "introducing peanut" is one of a small number of infant-safe forms:

• Thinned peanut butter, smooth and unsweetened, stirred into warm water, breast milk or formula until it is a loose, spoonable texture rather than a spoonful of paste on its own.
• Peanut butter mixed into a puree or plain yogurt the baby already eats, rather than served as a standalone food.
• Peanut powder or peanut flour, which dissolves into a puree without the sticky texture of butter and is easier to portion into the small amounts a first exposure calls for.

A first serving is a small amount, roughly the equivalent of two teaspoons of peanut butter thinned as above, watched for about ten minutes for any reaction before finishing the portion. If the first exposure goes without incident, the guidance calls for continuing peanut in the diet several times a week rather than treating one success as the end of the question. The protective effect in the LEAP data came from sustained, regular consumption over years, not a single cleared hurdle.

Egg follows a similar reversal in timing, introduced around the same six-month window in an age-appropriate cooked form (well-cooked egg mixed into a puree, not raw or undercooked), though it does not carry the same formal blood-test-or-skin-test protocol that NIAID built specifically around peanut. A baby who already has a diagnosed egg allergy is one of the two conditions that puts them in the high-risk peanut category above, which is the more consequential fact for feeding decisions at this stage.

What changed since the guidelines took effect

A study published in Pediatrics in 2025 looked at what actually happened in practice after early-introduction guidance became standard pediatric advice around 2021, comparing food allergy diagnosis rates before and after the shift. Peanut allergy diagnoses fell by roughly 27% and diagnoses of any IgE-mediated food allergy fell by roughly 38% in the children evaluated after the guidelines took hold, compared with the cohort evaluated before. The same data also showed a shift in which allergy shows up most often: peanut allergy had been the most commonly diagnosed food allergy before the guidance changed, and egg allergy took the top spot afterward, consistent with peanut-specific introduction advice doing more to move the peanut number specifically than the egg number.

That is real-world outcome data on top of the original trial, and the direction agrees: introduced early and consistently, the two allergens that used to be held back the longest now account for less of the diagnosed allergy than they did before the advice reversed.

What this does not cover

None of the above applies to a baby who has already shown a reaction to a food, whether hives, vomiting, or anything more severe: that is a case for a pediatrician or allergist before any further exposure, not a timing question this guide can answer. It also does not extend to introducing peanut, egg or any other allergen to a baby who is not yet developmentally ready for solids at all; the readiness signs (sitting with support, loss of the tongue-thrust reflex, interest in food) covered in homemade baby food safety come first, regardless of which food is next. And for a family running baby-led weaning instead of purees, the same allergen timing and forms apply: thinned peanut butter on a preloaded spoon or mixed into a soft food a baby can pick up, never a spoonful of peanut butter alone or a whole nut in any form.

The equipment question, what a baby actually eats this off of, is a separate decision covered in the high chair that fits a small kitchen and in the best feeding gear roundup for the rest of the weaning kit. This guide is only the timing and the testing question underneath all of it.

Sources

• NIAID, "Addendum Guidelines for the Prevention of Peanut Allergy in the United States"
• New England Journal of Medicine, "Randomized Trial of Peanut Consumption in Infants at Risk for Peanut Allergy"
• HealthyChildren.org (AAP), "When to Introduce Egg, Peanut Butter & Other Common Food Allergens to a Baby"
• HealthyChildren.org (AAP), "AAP Clinical Report Highlights Early Introduction of Peanut-based Foods to Prevent Allergies"

Questions people actually ask

What age should peanut actually be introduced?

Around six months for most infants, alongside other solid foods and with no testing required first. Infants with severe eczema or an existing egg allergy are the exception: NIAID guidance recommends introducing peanut earlier, at four to six months, but only after a peanut-specific IgE test or skin-prick test, generally with a pediatrician or allergist involved.

Does my baby need an allergy test before trying peanut?

Only if they have severe eczema requiring prescription treatment, an existing egg allergy, or both. For infants with no eczema or with mild to moderate eczema, home introduction around six months without prior testing is what the guidance describes.

How do you actually give a baby peanut butter without choking risk?

Never as a spoonful of peanut butter alone, and never as whole peanuts or tree nuts at any age this guide covers. Thin peanut butter with warm water, breast milk or formula until it is loose and spoonable, or stir it into a puree or yogurt the baby already eats. Peanut powder mixed into a puree is another accepted form.

Does introducing peanut early actually prevent allergy, or just delay it?

The randomized LEAP trial followed high-risk infants to age five and found the reduction held over that period: 3% peanut allergy in the group that ate peanut regularly versus 17% in the group that avoided it, a difference the trial attributed to sustained regular consumption rather than a single early exposure.

What about egg, dairy, and other allergens besides peanut?

The same early-introduction principle applies to egg, dairy, soy, wheat, sesame, and fish, generally introduced from around six months in age-appropriate, well-cooked forms. Peanut is the allergen with a formal NIAID testing protocol attached to it; the others follow the general early-introduction guidance without that specific blood-test-or-skin-test requirement.