How to Introduce Allergens to Your Baby Safely (Peanut, Egg, and More)
For years, parents were told to delay giving babies allergenic foods like peanut and egg. That advice has flipped. Major research and current guidance from bodies like the AAP now point the other way: introducing common allergens early, generally around when your baby starts solids, and keeping them in the diet, may actually help reduce the risk of developing a food allergy. If that gives you whiplash, you're not alone. This guide walks through how to introduce the major allergens safely, one step at a time, so you can do it with confidence rather than fear.
An important note before we start: this is general educational information. If your baby has severe eczema, an existing food allergy, or a strong family history of allergies, talk to your pediatrician before starting allergens, some babies should be assessed or introduced under medical guidance first.
Why the Advice Changed
The old "wait until age 1, 2, or 3" advice didn't reduce allergies, and rates kept climbing. Then landmark research (notably studies on early peanut introduction in high-risk infants) found the opposite: babies who were introduced to peanut early had dramatically lower rates of peanut allergy than those who avoided it. The current thinking is that early, regular exposure through eating helps the immune system learn to tolerate these foods.
The practical takeaway: for most babies, there's no reason to delay allergens, and good reason to introduce them around the start of solids and keep them in the rotation.
First, Make Sure Your Baby Is Ready for Solids
Allergen introduction happens within starting solids, so your baby needs to be developmentally ready for food first. The signs of readiness (usually around 6 months) are:
- Can sit up with support and hold their head steady.
- Has lost the tongue-thrust reflex (no longer automatically pushes food out).
- Shows genuine interest in food, reaching, leaning in, watching you eat.
A birthday isn't readiness, these signs are. Our starting solids guide covers the full picture, and the free solids readiness quiz helps you check where your baby is.
The Major Allergens to Introduce
Most food allergies are caused by a short list of foods. Aim to introduce these (in baby-safe forms) once solids are underway:
- Peanut (as smooth peanut butter thinned with water/milk, or peanut puffs, never whole nuts or thick globs)
- Egg (well-cooked)
- Cow's milk (as yogurt or cheese, not as a main drink before 12 months)
- Tree nuts (as smooth nut butters or ground, never whole)
- Soy
- Wheat
- Fish and shellfish (well-cooked, deboned)
- Sesame (as tahini thinned down)
Whole nuts, chunks of nut butter, and other hard or gloppy forms are choking hazards, always serve allergens in a smooth, thinned, or age-appropriate texture.
How to Introduce an Allergen: Step by Step
The method is simple and cautious:
- Introduce one new allergen at a time. That way, if there's a reaction, you know the culprit.
- Offer it early in the day, breakfast or lunch, not dinner, so you can watch your baby for the next couple of hours while you're both awake and alert. You do not want a first-time allergen right before bed.
- Start with a small amount. A little on the tip of a spoon, or a small taste, then wait 10 minutes. If all is well, offer a bit more.
- Do it at home, not at daycare or a restaurant, so you're in a calm, controlled setting.
- Watch for a reaction for about two hours (see the next section).
- If it's tolerated, keep it in the diet regularly, roughly a couple of times a week. This is the part people forget: ongoing exposure is what maintains tolerance. Introducing peanut once and never again isn't the goal.
- Wait a few days before the next new allergen, so each is tested cleanly. (You can keep offering already-tolerated foods in the meantime.)
Recognizing an Allergic Reaction
Most babies have no reaction at all. But you should know the signs so you can act.
Mild to moderate signs (most common)
- Hives (raised, red, itchy welts) or redness around the mouth or on the body
- Swelling of the lips, face, or eyes
- Itchiness, or a sudden flare of eczema
- Vomiting or loose stools shortly after eating
- Runny nose, sneezing, or mild wheeze
For a mild reaction (e.g., a few hives around the mouth), stop the food and call your pediatrician for guidance. They may recommend an antihistamine and a plan for next steps.
Severe signs (anaphylaxis, a medical emergency)
Call emergency services (911 or your local number) immediately if you see:
- Difficulty breathing, wheezing, or noisy breathing
- Swelling of the tongue or throat, or trouble swallowing
- A hoarse cry or voice, persistent cough, or choking sounds
- Widespread hives with vomiting, or paleness, floppiness, or unresponsiveness
- Any sudden, severe, whole-body reaction
Anaphylaxis is rare in a first introduction but is why we introduce one allergen at a time, in the morning, at home, with a phone nearby. If your baby has been prescribed an epinephrine auto-injector, use it as directed and still call emergency services.
Special Cases: Talk to Your Doctor First
Introduce allergens under medical guidance rather than solo if your baby:
- Has severe or persistent eczema (a known risk factor for food allergy).
- Already has a diagnosed food allergy (e.g., to egg).
- Has had a previous allergic reaction to any food.
- Has a sibling or parent with a significant food allergy and you're anxious about how to proceed.
Your pediatrician may recommend introducing certain allergens (like peanut) earlier and possibly with testing or in a monitored setting. This isn't about fear, it's about doing it the safest way for your specific baby. If you suspect a broader issue like cow's milk protein allergy, that guide covers the signs and diagnosis process.
Practical Ideas for Common Allergens
- Peanut: stir 1–2 teaspoons of smooth peanut butter into warm water, breast milk, or your baby's usual puree until thin and lump-free. Peanut puffs that dissolve are another easy option.
- Egg: well-cooked scrambled egg, hard-boiled egg mashed, or egg baked into food. Always fully cooked, no runny yolks.
- Dairy: full-fat plain yogurt or a little grated cheese (not cow's milk as a main drink until 12 months).
- Sesame: a little tahini stirred into puree or spread thinly.
- Fish: flaked, well-cooked, boneless white fish or salmon.
These fit naturally alongside first foods, our baby-led weaning first foods and first foods for baby guides give more texture and serving ideas.
Why Tracking Helps
When you're introducing new foods every few days, it's genuinely hard to remember what you offered, when, and whether there was any reaction, especially across two caregivers. Keeping a simple food log (food, date, any reaction) means that if something does flare, you have a clear record to show your pediatrician, which makes pinning down the cause far easier. You can log new foods and reactions, and share the record with your partner and doctor, using a free MyBabyTracker account.
When to Talk to Your Pediatrician
Beyond the emergency signs above, check in with your pediatrician if:
- Your baby has severe eczema, an existing allergy, or a strong family history, before you start allergens.
- Your baby has any mild reaction to a food, for guidance before offering it again.
- You're unsure how or when to introduce a particular allergen.
- Your baby has ongoing digestive symptoms, blood or mucus in stool, reflux, or poor growth that might point to a food intolerance or allergy.
- You'd feel more confident with a plan tailored to your baby, that's exactly what your pediatrician is there for.
This article is for informational purposes only and is not a substitute for professional medical advice.