Introducing Allergen Foods to Baby: When and How

Introducing allergen foods to your baby can feel nerve-wracking. Questions like "What if they have a reaction?" and "When is it safe to start?" are completely natural. The good news is that research in recent years has shifted how experts think about allergen introduction, and current guidelines generally encourage earlier exposure rather than delaying it.

This guide covers the major allergens, when to introduce them, how to do it safely, and what to watch for. As always, talk to your pediatrician before starting, especially if your baby has a family history of food allergies or conditions like eczema.

The Top Allergens to Know

The most common food allergens in babies and children (sometimes called the "top 9") are:

1. Cow's milk
2. Eggs
3. Peanuts
4. Tree nuts (almonds, walnuts, cashews, etc.)
5. Soy
6. Wheat
7. Fish
8. Shellfish
9. Sesame

These foods account for the majority of food allergies in young children. Not every baby will react to these foods, but it is important to introduce them thoughtfully and watch for any signs of a reaction.

When to Start Introducing Allergens

Current guidelines from major pediatric organizations recommend introducing allergenic foods early, typically around 6 months of age when your baby starts solids. Research, including the landmark LEAP study on peanuts, has shown that early introduction can actually reduce the risk of developing allergies.

For babies at high risk (those with severe eczema or an existing egg allergy), your pediatrician may recommend introducing peanuts even earlier, around 4 to 6 months. Always check with your pediatrician before starting, particularly if your baby has risk factors.

How to Introduce Allergen Foods Safely

Here are general best practices for introducing allergens:

• Introduce one new allergen at a time. Wait 2 to 3 days before introducing another so you can identify which food caused any reaction.
• Start with a small amount. Offer a tiny taste first and watch for any reaction before giving more.
• Introduce allergens at home, not at daycare or a restaurant. This way you can monitor your baby closely and have access to help if needed.
• Introduce allergens earlier in the day. This gives you more time to observe any delayed reactions before bedtime.
• Keep offering the food regularly. Once your baby tolerates an allergen, continue offering it a few times per week to maintain exposure.

Introducing Peanuts

Never give whole peanuts or chunky peanut butter to a baby, as these are choking hazards. Safe ways to introduce peanuts include:

• Mixing a small amount of smooth peanut butter with warm water, breast milk, or formula to thin it out
• Stirring peanut butter powder into baby cereal or purees
• Spreading a very thin layer of smooth peanut butter on a toast strip (for BLW babies)

Start with about half a teaspoon and watch your baby for at least 2 hours. Talk to your pediatrician about the right approach for your baby, especially if they have eczema or other allergies.

Introducing Eggs

Eggs are one of the most common allergens in babies. To introduce eggs:

• Start with well-cooked egg (scrambled or hard-boiled) since cooking can reduce the allergenicity of egg protein
• Offer a small amount first and wait to observe any reaction
• Once tolerated, eggs are an excellent source of protein and nutrients for babies

Introducing Dairy

While cow's milk should not be used as a main drink before 12 months (breast milk or formula should remain the primary milk source), dairy products like plain yogurt and small amounts of cheese can be introduced as solids around 6 months. These are generally well tolerated and provide calcium and protein.

If your baby has a known or suspected cow's milk allergy, talk to your pediatrician before introducing any dairy products.

Other Common Allergens

Wheat: Can be introduced through soft bread, pasta, or baby cereal. Start with a small portion and observe.

Soy: Found in tofu, edamame (mashed for young babies), and many processed foods. Offer small amounts initially.

Fish: Well-cooked, flaked fish with all bones removed is a great source of omega-3 fatty acids. Start with mild white fish.

Sesame: Mix a small amount of tahini (sesame paste) into purees or spread thinly on toast.

Tree nuts: Like peanuts, never offer whole nuts. Use nut butters thinned with water or mixed into foods.

Signs of an Allergic Reaction

Allergic reactions can range from mild to severe. Watch for these signs after introducing a new food:

• Mild: Small hives or red spots around the mouth, slight rash, or minor swelling
• Moderate: Widespread hives, significant swelling of face or lips, vomiting, or diarrhea
• Severe (anaphylaxis): Difficulty breathing, wheezing, throat tightening, pale or bluish skin, sudden limpness. This is a medical emergency.

What to Do If Your Baby Has a Reaction

For mild reactions (a few hives near the mouth that resolve quickly), note what your baby ate and when, and call your pediatrician to discuss next steps. Do not offer that food again until you have spoken with your doctor.

For severe reactions (difficulty breathing, widespread hives, vomiting, or any signs of anaphylaxis), call emergency services immediately. If you have been prescribed an epinephrine auto-injector, use it as directed.

It is always better to be cautious. If you are unsure whether a reaction is mild or serious, contact your pediatrician or seek emergency care.

Tracking Allergen Introductions

Keeping a record of which allergens your baby has tried, when they were introduced, and how your baby responded is extremely valuable. This information is helpful for your pediatrician and can save you from the confusion of trying to remember details weeks later.

With Remi, you can log new food introductions and any reactions quickly and easily. Just say what your baby ate and Remi tracks it for you.