When it happens · 5 min read
The allergen advice reversed, and nobody told you
If you had a baby before about 2017, you were probably told to hold off on peanut, egg and shellfish — the later the better, especially if allergies ran in the family.
That advice is gone. Not softened: reversed. Waiting does not protect a child, and for peanut the evidence says the opposite — introducing it early and keeping it in the diet is what lowers the risk. Plenty of parents on their second baby are still working from the old rules, because nobody sends a correction.
Last updated August 22, 2026
What the guidance says now
Around six months, when a baby is ready for solids, is when the common allergens can go in — egg, peanut, other nuts, dairy, wheat, soy, sesame, fish and shellfish. There is no benefit to delaying any of them.
Peanut is the one with its own timetable. For babies at higher risk — severe persistent eczema, or an existing egg allergy — the guidance is earlier still, as early as four to six months, and after a conversation with their doctor. For everyone else it goes in with the rest.
The other half of the finding gets lost: it is early introduction AND keeping it in the diet. A single taste at six months and nothing for a year is not what was studied.
The forms that are safe for a baby
A whole peanut is a choking hazard and so is a spoonful of thick peanut butter — it sticks in a lump to the roof of the mouth. Peanut aspirated into the lungs can cause a severe chemical pneumonia, which is a different and worse problem than choking.
Thin it instead. A small amount of smooth peanut butter stirred into infant cereal, pureed fruit or yoghurt, or dissolved in breast milk or formula and offered on a spoon. Peanut puffs that dissolve are another route for a baby who is already eating finger food.
Same principle for the others: cooked egg mashed or mixed in, not a boiled egg white in the hand. Fish flaked and checked for bones.
What a reaction looks like, and which one is an emergency
Most reactions are mild and show up within minutes to a couple of hours: hives or a rash, vomiting, diarrhea, or a flare of eczema. Stop that food and speak to your doctor before offering it again.
The emergency is different and it is not subtle. Trouble breathing, wheeze, swelling of the lips, tongue or face, a baby who goes pale, floppy or unresponsive — that is 911, not a phone call to the surgery. If a child has been prescribed adrenaline, use it and still call.
Introduce one new allergen at a time, earlier in the day rather than at bedtime, and when you are not about to drive somewhere. Not because a reaction is likely, but because it is easier to notice and act on when you are watching.
Who should ask first
A baby with severe, persistent eczema, or who has already had an immediate reaction to a food, should be discussed with their doctor before allergens go in. That is the group the early-peanut guidance was written around, and it may involve testing first.
A family history of allergy on its own is not a reason to delay. It is a reason to ask the question, get an answer specific to your child, and then start on time.
Common questions
- I delayed with my first child. Did I cause their allergy?
- No. You followed the advice you were given, which was the standard advice at the time and was given in good faith. The trials that changed it had not been done. Allergy has a lot of inputs and one timing decision made years ago is not something to carry.
- How often do I have to keep giving it?
- The protective effect in the research came from regular, continued servings rather than a single exposure — think a few times a week, folded into normal meals. If it drops out of the diet for a long stretch, ask your doctor before restarting rather than assuming it is still fine.
- Can I introduce allergens before six months?
- For most babies, solids start around six months and allergens go in with them. The four-to-six-month window is specific to peanut and to babies at higher risk, and it is a conversation to have with their doctor rather than something to start on your own.
Still not sure
This page is the general answer. Yours is a specific child.
The advisor can be. It has read everything here, and it knows how old your children actually are — which is the whole difference wherever guidance changes with age. Ask it anything.
- She's got a temperature of 100. Is that something to worry about?
- He's obsessed with space and galaxies — what toys are worth getting him?
Free. It comes with the note.
It answers from the same cited pages you are reading, and when the question is where to go, from the real clinician, hospital and childcare records behind this site — not a link to go search them yourself. It says so when we have not written about something, and it is not a doctor; for anything urgent it gives you the threshold and tells you to call.
Where this comes from
- When to introduce egg, peanut butter and other common food allergens to a babyAAP
- Early introduction of peanut-based foods to prevent allergiesAAP
- Guidelines for the diagnosis and management of food allergyNIAID
- Choking prevention and what to doAAP
Every claim on this page traces to one of these. See every source we use →
Written from the sources named above, and it is not a substitute for your own doctor. If something feels wrong to you, that instinct is a good enough reason to call — you know yourself and this family better than any page does.