How to Introduce Allergens to Your Baby Safely

Learn the safe, step-by-step approach to introducing common allergens to your baby to reduce allergy risk.

1. When to Start Introducing Allergens. Most pediatricians recommend introducing allergens between 4-6 months of age, after your baby has started eating solid foods and can sit up with support. Your baby should be developmentally ready for solids - able to hold their head steady, show interest in food, and move food to the back of their mouth to swallow. Don't wait too long though. Research shows introducing allergens between 4-11 months is most effective for preventing allergies. Always check with your pediatrician first, especially if your family has a history of food allergies or if your baby has severe eczema.
2. The Big 8 Allergens to Introduce. Focus on the eight most common allergens: eggs, milk, peanuts, tree nuts, fish, shellfish, wheat, and soy. You don't need to introduce them all at once - in fact, you shouldn't. Start with one new allergen every 3-5 days so you can watch for reactions. Peanuts and eggs are often good first choices since they're easier to prepare safely for babies. Remember that cow's milk as a drink isn't recommended until after 12 months, but milk in foods like yogurt or cheese is fine earlier.
3. How to Prepare Allergens Safely. Make allergens baby-safe by preparing them appropriately for your little one's age. For peanuts, use smooth peanut butter thinned with breast milk, formula, or water - never give whole peanuts or chunky peanut butter to babies. For eggs, start with well-cooked scrambled eggs cut into small pieces. Fish should be fully cooked, boneless, and flaked into tiny pieces. Tree nuts should be ground into nut butter or flour, never given whole. Always ensure foods are soft enough for your baby to gum and swallow safely.
4. Introducing One Allergen at a Time. Give your baby a small amount of the new allergen food - about 1/4 to 1/2 teaspoon to start. Offer it during the day, preferably at breakfast or lunch, so you can monitor for reactions while you're awake and alert. Give the same allergen for 3-5 days in a row before introducing the next one. This repetition helps with tolerance building and makes it easier to identify which food caused a reaction if one occurs. If your baby tolerates the food well, you can gradually increase the amount and continue offering it regularly as part of their diet.
5. Watching for Allergic Reactions. Most allergic reactions happen within minutes to 2 hours after eating. Mild reactions might include hives, rash around the mouth, runny nose, or mild stomach upset. More serious reactions include vomiting, diarrhea, difficulty breathing, swelling of face or tongue, or extreme fussiness. If you see any concerning symptoms, stop giving that food and contact your pediatrician. For severe reactions like difficulty breathing or swelling, call 911 immediately. Keep a food diary to track what you've introduced and any reactions you notice.
6. Building Allergen Foods into Regular Meals. Once your baby tolerates an allergen well, keep offering it regularly - about 2-3 times per week. This ongoing exposure helps maintain tolerance. Mix allergen foods into meals your baby already enjoys. Add a little peanut butter to oatmeal, offer scrambled eggs with vegetables, or give small pieces of cheese as finger foods. The goal is making these foods a normal part of your baby's diet, not just a one-time introduction. This regular exposure is what helps prevent allergies from developing later.