The Big 9 allergens schedule

Track each allergen as you introduce it with the First Foods Tracker. Date, food, reaction. Your pediatrician will ask.

What changed about allergen guidance

The old advice was to delay allergens until 12 months or even later. That advice has been completely overturned. Multiple major studies (LEAP, EAT, others) showed early introduction reduces allergy rates, in some cases dramatically. The 2017 NIAID guidelines and current AAP advice both recommend introducing common allergens starting around 6 months, alongside other solid foods.

For peanut specifically, high-risk babies (severe eczema, egg allergy) should be introduced as early as 4 to 6 months — talk to your pediatrician first. For most babies, 6 months and onward is fine.

The Big 9 allergens

1. Peanut
2. Egg
3. Milk (cow's milk protein)
4. Soy
5. Wheat
6. Tree nuts (almond, cashew, walnut, etc.)
7. Fish
8. Shellfish
9. Sesame

These cause about 90% of food allergy reactions. Introduce each one, then keep offering it 2 to 3 times per week to maintain tolerance. Stopping for several weeks can sometimes re-trigger sensitization.

The introduction rules

• One new allergen per day. If two new foods cause a reaction, you won't know which one.
• Morning is best. If reaction occurs, you have daytime hours to call the pediatrician and observe.
• Baby should be healthy. Not sick, not in the middle of teething hard, not on the day of vaccines.
• Home, not restaurant or daycare. You need to know exactly what's in the food.
• Small amount first. Start with about an eighth of a teaspoon mixed into a familiar food. If no reaction in 10 minutes, give a bigger portion.
• Watch for 2 hours. Most IgE-mediated reactions appear in this window.
• Wait 24 hours before the next new allergen. Some delayed reactions can show up at the 4 to 6 hour mark or later.

The day-by-day schedule

This is a sample 9-day schedule. Slot the allergens into days when baby is well and you can be home in the morning. Doesn't need to be back-to-back — works fine spread over 2 to 3 weeks.

Day 1: Peanut

Mix 1/2 teaspoon smooth peanut butter with 2 teaspoons of warm water or breast milk to thin. Or use peanut puffs dissolved in a little water. Do NOT give a spoonful of straight peanut butter — choking hazard. First spoonful: tiny taste. Wait 10 minutes. If no reaction, offer the rest.

Day 2: Cow's milk dairy

Whole-milk plain yogurt is the easiest first dairy. Offer 1 to 2 teaspoons. If baby's already had cow's milk through formula, this isn't really a "first" — note any reaction either way.

Day 3: Egg

Scrambled egg, well-cooked. Mix a small amount of yolk and white. Mash and offer 1 to 2 teaspoons. Don't separate yolk and white — full egg is current guidance.

Day 4: Wheat

Pasta well-cooked and chopped, or a soft piece of toast. Or wheat-based infant cereal. About 1 to 2 tablespoons.

Day 5: Soy

Silken tofu mashed, or unsweetened soy yogurt. 1 to 2 teaspoons.

Day 6: Tree nut (almond)

Almond butter, thinned with water or breast milk. Same prep as peanut. Start with one tree nut variety. Add others (cashew, walnut) one at a time on subsequent days.

Day 7: Fish (low-mercury)

Cooked salmon, cod, or tilapia. Carefully de-boned. Mash a small amount. Avoid high-mercury fish.

Day 8: Shellfish

Shrimp is the most common choice. Cook thoroughly. Chop very finely (shrimp can be a choking shape). Offer about 1 teaspoon mashed.

Day 9: Sesame

Tahini thinned with water. About 1/4 teaspoon mixed into a familiar food. Sesame is the most recently added allergen to the Big 9 and is increasing in prevalence in the US.

What a reaction looks like

Mild (still call pediatrician but not emergency)

• A few hives appearing near the mouth or on the face.
• Mild facial swelling that doesn't worsen.
• Some redness or rash.
• One or two vomits without other symptoms.
• Mild diarrhea later that day.

Call your pediatrician for next steps. They may want you to come in or watch from home. Don't introduce more allergens until you've talked.

Severe (call 911)

• Hives spreading rapidly across the body.
• Swelling of lips, tongue, or face that's progressing.
• Difficulty breathing, wheezing, or stridor (high-pitched breathing sound).
• Pale, floppy, or unresponsive baby.
• Repeated vomiting plus other symptoms.
• Drooling, drooping face, or trouble swallowing.

Call 911 immediately. Do not wait to see if it gets better. Severe reactions (anaphylaxis) can progress fast.

What to have on hand before you start

• Liquid infant antihistamine (Benadryl or similar) — talk to your pediatrician about dose for your baby's weight before starting allergens.
• Pediatrician's phone number and address.
• Nearest ER address and route.
• 911 ready on your phone.
• An EpiPen if your pediatrician has prescribed one (high-risk babies).

Most reactions don't go anywhere near this. But having the plan in place means you don't have to think under stress.

Babies at higher risk

Talk to your pediatrician about earlier and more careful introduction if your baby has:

• Severe eczema.
• A diagnosed egg allergy (predicts higher peanut risk).
• A sibling with significant food allergies.
• Family history of anaphylaxis.

For these babies, your pediatrician may want allergen introduction to happen in-office, or recommend allergy testing first. Don't go solo.

The "keep offering" part

Introducing once isn't enough. To maintain tolerance, keep offering each allergen 2 to 3 times per week. Easy maintenance ideas:

• Peanut: Smooth peanut butter on toast strips, peanut puffs as a snack.
• Egg: Scrambled egg with breakfast or as part of pancakes/muffins.
• Dairy: Yogurt, cheese, milk in cooking.
• Soy: Tofu in meals.
• Wheat: Pasta, bread, crackers.
• Tree nut: Almond or cashew butter in oatmeal.
• Fish: Salmon or cod twice a week.
• Shellfish: Less frequent but rotate in.
• Sesame: Tahini in hummus, sesame seeds on toast.

Common mistakes

• Introducing all 9 in the same week — you can't tell what caused a reaction.
• Introducing in the evening — limits your response window.
• Introducing during illness or vaccines — symptoms blur together.
• Introducing once and never again — sensitization can re-develop.
• Skipping allergens out of fear — increases risk of actual allergy.
• Using straight peanut butter without thinning — choking hazard.

When to talk to your pediatrician

• Before starting if your baby has eczema, egg allergy, or strong family history.
• After any reaction — mild or severe.
• If you're nervous and want guidance on dosing.
• If your baby gags or refuses every allergen attempt.
• If symptoms appear hours later (delayed reactions are real).

Allergen introduction is one of the higher-stakes parts of starting solids. Going slow, sticking to the rules, and keeping your pediatrician's number close makes it routine.