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Allergens and introducing common foods
Current guidance has moved away from delaying common allergenic foods for no reason. For many infants, introducing allergenic foods once the baby is developmentally ready for solids is part of current best practice rather than something to postpone 123.
What foods count as common allergens
The usual list includes peanut, egg, dairy, wheat, soy, sesame, fish, shellfish, and tree nuts in age-appropriate forms 12. The practical goal is not to turn every introduction into a stress test. It is to introduce them safely, in forms the baby can handle, while watching for reactions.
The texture matters as much as the ingredient. Peanut butter should be thinned or mixed into a safe texture, nut pieces should stay out, and anything that can block the airway should stay off the menu until the child can manage it safely 12.
Why early introduction changed practice
The biggest shift came from peanut allergy prevention evidence. The LEAP trial found substantially lower peanut allergy rates among high-risk infants who consumed peanut compared with those who avoided it, and later guidance built on those findings 34. That does not mean every allergen has identical evidence strength, but it did change the broader approach from "delay by default" to "introduce thoughtfully when ready" 123.
When to be more cautious
If a baby has severe eczema, known egg allergy, or another significant allergy history, speak with the clinician before peanut introduction because some infants benefit from earlier structured planning, testing, or supervised introduction 13. For infants without those risk factors, common allergenic foods are often introduced at home in age-appropriate forms once other solids have started 12.
What the evidence suggests
The NIAID peanut guideline recommends earlier peanut introduction, especially for higher-risk infants, because the balance of evidence suggests prevention benefit rather than harm when introduction is done in an age-appropriate way 3. The LEAP data are strongest for peanut and especially informative for infants with eczema or egg allergy; they are not a reason to improvise unsafe textures or skip discussion when a child already seems likely to react 34.
Practical introduction approach
- introduce allergens in forms that are safe for the baby's texture skills
- choose a time when you can watch the baby afterward
- introduce one new major allergen at a time if you want to keep reactions easier to interpret
- once tolerated, keep the food in regular rotation instead of treating it like a one-time event
What a reaction can look like
Reactions can show up in the skin, gut, or breathing. Mild examples include hives, redness, itching, a rash around the mouth, vomiting, or diarrhea 56. More concerning symptoms include swelling of the lips, tongue, or throat, coughing, wheezing, trouble breathing, repeated vomiting, or a baby who seems floppy, pale, or hard to wake 56.
What to do if there is a reaction
Stop the food. If the reaction is mild and the baby is otherwise well, call the clinician the same day or follow the office's after-hours guidance 56. If there is any breathing trouble, throat swelling, or the baby looks unwell beyond a simple skin reaction, seek emergency care immediately 56.
How often to keep tolerated foods in rotation
Once a food is tolerated, keep it in the menu regularly rather than making it a one-time experiment 12. The goal is normal exposure, not a ceremonial introduction with applause.