Many parents worry that common allergens should be delayed, especially if there is a family history of allergy. Current evidence supports a different approach: for most babies, introducing common allergenic foods in an age-appropriate form during the first year may help your baby become familiar with those foods, and delaying them does not appear to prevent allergy.
The best-known studies in this area, including LEAP and EAT, changed how clinicians think about peanut and other allergens. In 2019, the American Academy of Pediatrics aligned with this newer evidence and moved away from routine delay recommendations for most infants. If your baby has severe eczema, a known food allergy, or another high-risk condition, ask your pediatrician for individualized advice before introducing allergenic foods.
What counts as a common allergen?
Common allergenic foods include peanut, egg, cow’s milk, tree nuts, soy, wheat, sesame, fish, and shellfish. Not every baby will react to these foods, and being exposed to them early does not mean your baby will become allergic. The main goal is to introduce foods safely, one at a time, in forms that are safe for your baby’s developmental stage.
When to start
Most babies are ready for solids around 6 months, when they can sit with support, have good head control, and show interest in food. Some babies may be ready a little earlier or later. The timing of allergen introduction should follow the same readiness signs you use for other first foods.
You do not need to wait days or weeks between every new allergen forever. A practical approach is to introduce one new food at a time earlier in the day, when you can watch your baby for a reaction. Once a food has been tolerated, keep offering it regularly as part of your baby’s diet.
How to introduce peanut safely
Peanut deserves special attention because it is one of the more common childhood food allergens. Evidence from the LEAP trial showed that early, regular peanut consumption in infants at high risk of peanut allergy reduced later peanut allergy compared with avoidance. That does not mean every baby needs a medical test first, but it does support earlier introduction for most infants when done safely.
If your baby has severe eczema, a prior immediate reaction to a food, or a diagnosed egg allergy, talk with your pediatrician before introducing peanut. Some higher-risk babies benefit from a more structured plan.
Introducing egg, dairy, fish, and other allergens
The EAT trial and later guidance support introducing several allergenic foods during infancy rather than postponing them. For many families, the easiest way is to mix a small amount of the allergen into a familiar food your baby already tolerates. The food should be fully cooked or otherwise age-appropriate in texture.
A simple way to keep track is to introduce one allergen at a time on separate days, then repeat each tolerated food regularly. Regular exposure matters more than a single taste.
What a normal first exposure looks like
Most babies tolerate a new allergen without any problem. Mild spit-up or a brief grimace does not necessarily mean an allergy. True allergic reactions usually happen soon after eating and often involve more than one body system, such as skin, breathing, or vomiting.
Signs of an allergic reaction
Allergic reactions can range from mild to severe. Mild symptoms may include a few hives, redness around the mouth, or mild itching. More serious reactions can involve swelling, repeated vomiting, coughing, wheezing, trouble breathing, or sleepiness. Symptoms usually start soon after the food is eaten, often within minutes to 2 hours.
Call emergency services now if your baby has trouble breathing, lip or tongue swelling, widespread hives with vomiting, becomes very floppy or difficult to wake, or you are worried about anaphylaxis. If your baby has an epinephrine auto-injector, use it as directed and seek emergency care.
How often should you keep offering tolerated allergens?
After your baby has eaten a food without a reaction, keep including it in the diet. There is no exact universal schedule, but regular inclusion is a sensible goal. If a tolerated allergen disappears from the diet for a long time, it may be harder to keep it familiar in the menu.
Special situations
Some babies need a more cautious plan. That includes babies with severe eczema, a previous food reaction, multiple food allergies, poor growth, or medical conditions that affect feeding. If your baby was born very prematurely or has complex medical needs, your pediatrician may suggest a different timeline or specific supervision for first exposures.
If you have a strong family history of allergy, it is still often reasonable to introduce allergens, but family history alone does not automatically mean your baby will react. Your pediatrician can help you decide whether any testing or supervision is appropriate before the first exposure to peanut or other foods.
When to call your pediatrician
This guide is for educational purposes only and is not a substitute for medical advice. Always consult your pediatrician before making decisions about your baby's feeding or care.
