How to Introduce Allergens to Your Baby: Peanut, Egg, and Dairy

Introducing the big food allergens used to feel scary, and for years parents were told to wait. The advice has flipped. We now have strong evidence that offering allergens early and keeping them in your baby's diet can actually lower the chance of a food allergy. That is good news, and it makes the job simpler than it sounds.

This is a practical, do-it-this-week guide to peanut, egg, and dairy: when to start, how to prepare each one safely, and how to keep them in the rotation. Every baby is different, ranges are wide, and your pediatrician knows your baby's history. Use this as a roadmap, not a rulebook.

When to start and why earlier is better

For most babies, allergen introduction begins around 6 months, once they can sit with support, hold their head steady, and show interest in food. Peanut is the exception worth flagging: guidance from the American Academy of Pediatrics suggests introducing peanut-containing foods as early as 4 to 6 months for many babies, alongside other first foods When to Introduce Common Allergens.

The reason for the shift is solid research. Studies found no benefit to delaying allergens, and early, regular peanut exposure prevented peanut allergy in many high-risk infants. The takeaway is that waiting does not protect your baby, and may do the opposite.

One special case: severe eczema or known egg allergy

Babies with severe eczema or an existing egg allergy are at higher risk for peanut allergy. If that is your baby, talk to your pediatrician before the first peanut taste. They may recommend earlier introduction, allergy testing, or doing the first try in the office American Academy of Pediatrics. This is the one situation where you should not freelance the timing.

How to introduce peanut safely

Whole peanuts and globs of thick peanut butter are choking hazards for babies, so the trick is to thin it out. Never give a baby whole nuts or a spoonful of stiff peanut butter.

Here is a simple method:

1. Stir 2 teaspoons of smooth peanut butter into 2 to 3 teaspoons of warm water, breast milk, or formula until it is a thin, smooth puree.
2. Offer a small taste on a spoon, or mix a little into a fruit or cereal your baby already eats.
3. Do the first taste at home, earlier in the day, when you can watch your baby for a couple of hours and a clinic is open.

If there is no reaction, gradually work up to the full amount and keep peanut in the rotation. You can also use thinned peanut puff snacks designed for babies, which dissolve easily. The AAP notes peanut can be mixed into cereal, pureed fruit, or yogurt, or dissolved in breast milk or formula and given by spoon When to Introduce Common Allergens.

How to introduce egg

Egg is one of the most common childhood allergens, and it is easy to prepare. The key rule: always cook it well. Raw or runny egg is both a food-safety risk and not the form you want for a first taste.

Offer well-cooked egg, such as a hard-boiled egg or scrambled egg, in a baby-friendly form:

• Mash a hard-boiled egg with a little water, breast milk, or a familiar puree.
• Cut a soft scramble into small, smushable pieces for babies doing finger foods.
• Start with roughly one-third of an egg as a first portion, then build up if tolerated.

As with peanut, do the first try at home and watch your baby. Once egg is tolerated, keep offering it regularly so the exposure stays steady.

How to introduce dairy (without cow's milk as a drink)

Dairy trips a lot of parents up because of one detail: plain cow's milk as a main drink is not recommended before age 1. But that does not mean dairy is off-limits. The milk protein in foods like yogurt and cheese can be introduced earlier.

The easy on-ramp is plain whole-milk yogurt:

• Offer a spoonful of plain whole-milk or Greek yogurt, ideally mixed with a fruit your baby has already had.
• A little soft cheese or cheese melted into another food also works.
• Skip flavored, sugary yogurts and save cow's milk as a beverage for after the first birthday.

This introduces the dairy protein safely while breast milk or formula stays your baby's main drink.

Keep them in the rotation (this part matters most)

The single biggest mistake is treating allergen introduction as a one-and-done checkbox. A first taste is not enough. Protection comes from regular, ongoing exposure.

Once your baby tolerates an allergen, keep offering it about twice a week in age-appropriate amounts When to Introduce Common Allergens. Small counts: a smear of thinned peanut on toast, a few bites of egg, a spoon of yogurt.

Go one allergen at a time

Introduce one new allergen, then give it a few days before adding the next. If a reaction shows up, you will know which food caused it. The other big allergens worth working through over the coming weeks include tree nuts (as smooth butters), sesame (tahini thinned out), soy, wheat, fish, and shellfish.

Watch for reactions and know when to call

Most reactions appear within minutes to about two hours. Mild signs include hives, redness or swelling around the mouth, or vomiting. A severe reaction is an emergency: trouble breathing, swelling of the lips or tongue, repeated vomiting, wheezing, or a pale, floppy baby. Call 911 for any severe symptoms. For mild symptoms, stop the food and call your pediatrician for guidance before trying it again. When in doubt, call your child's provider. They would rather hear from you than have you guess.