Written by: Xenos Wooten Sep 25, 2023

Common Pediatric Food Allergies

If your child has had a recent diagnosis of a food allergy, you might be wondering what exactly is a food allergy? What are common pediatric food allergies? Or maybe what kinds of foods can cause an allergic reaction? Are there other foods my child should avoid if they already have one diagnosed allergy? What is cross-reactivity in food allergies? How do I protect my child from having serious food allergies? Here are some answers to some of the most common questions about food allergies. Be sure to consult with your child’s allergist for individualized care.

• What is an allergic reaction to food?

An allergic reaction occurs whenever the immune system is triggered by something it deems to be a foreign invader to the body. When an allergen is ingested, the immune system sends out various components, including antibodies (called immunoglobulins) and white blood cells that cause a range of symptoms ranging from mild to severe. Immunoglobulin E (IgE) is often the main culprit in the rapid onset of allergy symptoms; IgE circulating in the bloodstream can cause swelling and itching of the tongue and mouth, runny nose or watery eyes, increased heart rate, difficulty breathing, coughing, wheezing, vomiting, and even dizziness or confusion, and usually occurs within minutes of ingesting an allergen. Chronic release of immune cells can also disrupt the natural barrier of the skin and cause an itchy, dry, irritated rash called atopic dermatitis or eczema.

• What types of foods can you be allergic to?

In theory, anyone can be allergic to anything if it triggers their immune system. However, 90% of all food allergies are from one of nine foods: milk, eggs, peanuts, tree nuts, fish, shellfish, soy, wheat, and sesame. For infants, cow’s milk protein is very often the culprit as it is a main ingredient in infant formula and is often poorly tolerated by the immature digestive tract and immune system. 

Depending on the allergen and the type of allergic response, sometimes cooking the food at high temperatures changes the protein enough that an allergic response does not occur. For instance, about 70% of children with milk or egg allergies can eat baked goods containing eggs and milk without triggering a reaction.

• Can you be allergic to more than one food?

Yes, it is absolutely possible to be allergic to more than one food, and in fact, it is fairly common. A recent study showed that 40% of children and 48% of adults with a diagnosed food allergy also had an allergy to more than one food. This can make avoiding allergens and meal planning more complex, especially for small children. Multiple food allergies complicate allergy care.

• Will my child outgrow their food allergy?

Whether or not a child outgrows their food allergy depends largely on which food they are allergic to. Up to 50% of infants are able to tolerate cow’s milk by their first year of age and 90% can tolerate it by three years old. Other childhood allergies may be outgrown as well, with 80% of children eventually outgrowing egg, milk, and wheat allergies. However, peanut/tree nut and seafood allergies often last into adulthood and for life, with only 20% outgrowing those allergies in childhood.

• How can I prevent food allergies in my baby?

Current evidence suggests that the best way to avoid food allergies in young children is by early exposure to common allergens. This can be done by introducing a variety of foods in small, soft pieces once your baby is able to sit upright on their own, usually around six months old. Products such as peanut powder exist specifically to be mixed into purees or sprinkled onto baby foods to allow children to consume these proteins without the choking hazard of giving whole nuts or nut butters to infants. If you have a strong family history of food allergies, this does increase your child’s risk of having food allergies as well, so talk to your child’s pediatrician or pediatric allergist to make a plan that works for your family. Whenever any new food is introduced, babies should be watched closely for any sort of rash, coughing, choking, or other reaction over a period of time.

• If my child has a food allergy, are there other foods they should avoid?

This is a tricky question, and the answer really depends on what other types of foods you are talking about. The U.S Drug and Food Administration (FDA) currently requires all food manufacturers to clearly label all foods containing or potentially contaminated with any of the 9 most common allergens (milk, eggs, fish, shellfish, tree nuts, peanuts, wheat, soy, and sesame). However, for some allergens, there are other names or “hidden” ingredients that may actually contain your child’s food allergen even if it is not clearly labeled; you will need to avoid those as well. For example, ingredients such as tofu, tempeh, miso, and edamame all actually contain soy. Or ingredients such as casein, whey, ghee, and custard all contain dairy. So while you are reading food labels and avoiding a specific food, you need to be familiar with other ingredients derived from that food and avoid those as well.

• What are cross-reactive foods and how does it affect my child?

Another major consideration in managing food allergies in children is the role of cross-reactive foods in food allergy care. Cross-reactivity occurs when the protein of one food is similar enough to the protein of another food that the body cannot tell the difference. This can cause a positive skin or blood allergen test with or without an actual reaction occurring. 

Sometimes, a confirmed cross-reactivity might lead a person to avoid a food that they are not truly allergic to and will not experience allergic reaction symptoms if consumed. Other times, a person with a food allergy may experience a reaction to similar foods. For example, children with an allergy to cow’s milk have a 90% chance of experiencing a similar reaction to goat’s milk. About 50% of children with a peanut allergy also test positive for other legumes (like soy), but up to 95% of those children can actually eat other legumes without a reaction. Careful testing and discussion with your child’s allergist about possible cross-reactivity and what this means for your child’s treatment plan is necessary to get the best of your child’s allergy care.