When should we introduce allergens, and how?

An estimated 90 percent of all food allergies are caused by the following nine foods: milk, eggs, wheat, soy, tree nuts, peanuts, fish, sesame and shellfish. Nearly 5 percent of children under the age of five years have food allergies, and although many children "outgrow" their allergies, allergies to peanuts, tree nuts, fish, and shellfish may be lifelong.

Not all food allergies can be prevented, however, studies show that the best prevention of food allergies to peanuts and eggs is early and frequent consumption. Introducing small amounts of egg or peanuts early on may reduce the chances of developing food allergies, especially in babies with eczema, as recommended by the American Academy of Pediatrics.

 When introducing common food allergens, stick to one per day so that you can easily identify which new food causes a reaction, if one occurs. If nothing happens, continue with the new food several times a week as part of a varied diet. Introducing a new food and not making it a consistent part of your child’s diet could cause allergies to develop, so it is important to stay consistent once a food allergen is introduced. If your child has a reaction, discontinue feeding the offending food until you’ve spoken to a doctor.

It does not take much food to cause a severe reaction — even a small fraction of a peanut kernel can affect some severely allergic children. Some foods may not cause a reaction until the second time your child is eating something so monitor multiple feedings for any reactions that may indicate an allergy to that food.

Food allergies generate an immune system response which can cause symptoms ranging from discomfort to life-threatening reactions. These can include hives, asthma, itching, trouble breathing, stomach pains, vomiting, and/or diarrhea. Food intolerance, which occurs when a person has difficulty digesting a certain food, is not an immune response but may also involve some of the same symptoms as a food allergy. Because allergy symptoms can overlap with intolerance and even other conditions like colic, you should speak with your child’s doctor if you suspect an allergy. 

This article has been reviewed by our team of experts.

Disclaimer: The contents of this article does not constitute medical advice. If you have concerns about any health or medical condition, diagnosis, or treatment you should consult with your pediatrician or a licensed healthcare provider.