Children's Hospital Colorado

All About Child Food Allergies

Smiling baby eating a cracker

Most parents don’t know their child has a food allergy until they try a food for the first time and experience an allergic reaction, though not all children will react to the food upon first exposure. Allergic reactions can range from mild to severe, which is why it’s good to understand recommendations on introducing kids to new foods, how to spot an allergic reaction and when to seek care.

Introducing foods and watching for an allergic reaction in babies

One of the top recommendations for parents on how to identify food allergies in children is to start by introducing one food at a time. That way, it’s easier to tie a reaction to a specific food. Typical allergenic foods can be introduced 2 to 3 days apart, but there isn’t a particular timeline for introduction of other foods. Babies should eat a variety of foods by the time they’re 12 months old and waiting to offer different foods for unnecessary periods can negatively affect variety or diversity.

The type of food or the order in which you introduce food to your baby doesn’t really matter, as long as the foods you’re giving them are healthy and well-balanced. When you give a new food, you don’t need to eliminate the other foods your baby is eating. You already know those foods are safe because your baby hasn’t had any reactions up to this point.

Typical allergenic foods

There are specific recommendations on when to introduce peanuts and eggs — two of the major foods that are often associated with pediatric food allergies. You can introduce peanuts and boiled, heated or well-cooked eggs as early as 4 to 6 months old. Research, including the LEAP study and the EAT study, shows that earlier introduction may prevent the development of a food allergy. However, children with severe eczema or a previous allergic reaction to a food should consider seeing their primary care provider or an allergist before eating these foods.

There is limited information about the introduction of milk and wheat as it relates to preventing the development of food allergy, and there is no information about soy, tree nuts, fish and shellfish. You should talk with your child’s primary care provider about the right time to introduce these foods.

Breastfeeding your child can lower their risk of developing a milk allergy. When breastfeeding is not an option, formula can help. Some babies may not tolerate certain milk or soy formulas. If you think your child isn’t tolerating a formula or may have a milk or soy allergy, talk with your doctor about testing and ask about reputable alternative formulas. Some European baby formulas are advertised heavily online, but they’re actually illegal to sell in the United States because they’re not regulated by the Food and Drug Administration (FDA). These types of formulas are not recommend for babies in the United States, so it’s always best to ask your doctor for recommendations.

Recognizing allergic food reactions in kids

Food allergies are typically divided into two types: IgE-mediated and non-IgE mediated. Symptoms and reaction times are different depending on the type. In terms of IgE mediated food allergies, you’ll know when your child is allergic to something because they’ll usually react right away or within 1 to 2 hours.

IgE-meditated food allergy

If your child has an IgE-mediated food allergy (or an allergy that results from eating common allergy foods like milk, eggs, peanuts, etc.) you’ll likely see a reaction within minutes to a couple of hours. Keep an eye out for the following symptoms. If you notice these symptoms, you should call your primary care provider.

  • Hives or welts
  • Flushed skin or rash
  • Swelling of the face, tongue or lips
  • Vomiting
  • Diarrhea
  • Coughing or wheezing

A serious allergic reaction with widespread effects on the body is known as anaphylaxis. This sudden, potentially life-threatening, allergic reaction requires immediate medical attention and you should call 911 if you notice the following symptoms:

  • Hoarseness
  • A sensation of tightness in the throat
  • Difficulty breathing
  • Loss of consciousness
  • Any symptoms from two or more of the body systems, such as hives and stomach pain, or any other combination of two or more symptoms that affect different parts of the body

Non-IgE mediated food allergy

Other types of food allergy, called non-IgE mediated food allergy, can have delayed reactions occurring more than two hours after ingestion and may be more difficult to identify due to the delay in symptoms. Reactions typically involve the gastrointestinal tract and include vomiting, bloating and diarrhea. A common non-IgE mediated food allergy is food protein-induced enterocolitis, or FPIES. You should contact your primary care provider if you think your child is showing symptoms of a non-IgE mediated food allergy or see a pediatric allergist who may recommend an elimination diet.

Learn more about how to help your child live with a food allergy and how the pediatric experts at Children’s Colorado’s Allergy and Immunology Center can help.


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