Top 9 food allergies for babies: : Signs & when to introduce

Food allergies affect about 8% of children in the United States [1], and in recent years, that number has been on the rise. Understandably, many parents worry about introducing high-allergen foods to their babies when starting solids. Keep reading for more information on everything you need to know about the top allergy foods for babies, including when to introduce them. 

What causes food allergies in babies?

Food allergies happen when the body’s immune system mistakes a protein in food as harmful and tries to fight it off. The immune response causes the common signs and symptoms associated with allergies.

While the exact cause of food allergies [6] is unknown, they do tend to run in families and people with eczema, asthma, or hay fever are more likely to develop food allergies. The first signs of a food allergy usually occur in childhood, but they can develop at any age.

Top 9 high allergy foods for babies

According to Johns Hopkins Medicine, the following foods are responsible for 90% of food allergies in children [2]: 

• Milk

• Eggs

• Wheat

• Shellfish

• Fish

• Tree nuts

• Peanuts

• Soy

• Sesame

When should you introduce high-allergy foods to your baby?

For most families, introducing high-allergy foods to your baby can begin as soon as you begin solid foods (more about baby-led weaning and purees here). If you have a family history of food allergies or eczema, be sure to discuss introducing high-allergy foods with your pediatrician as a different approach may be necessary. 

While previous guidance recommended delaying the introduction of the top allergenic foods, the American Academy of Pediatrics (AAP) updated these guidelines in 2018 to reflect the latest research. In fact, the early introduction of high-allergy foods, such as peanuts, may help to reduce the likelihood of food allergies [3]. 

It is still best practice to introduce one top allergenic food at a time in order to best be able to identify the cause if an adverse reaction occurs. 

Things to know about each allergenic foods

Milk

Cow’s milk allergy occurs when the body reacts to a protein found in cow’s milk or cow’s milk products such as cheese or yogurt. It is different from lactose intolerance and is a common food allergy in young children. Cow’s milk should not be introduced as a beverage to babies under one, but you can introduce yogurt or cheese. 

Eggs

Eggs are another common allergy in young children and many times it is outgrown. Some people with egg allergies can eat them when they are baked in a dish like a cake or a cookie. When introducing eggs to your baby make sure they are well-cooked. Popular egg preparations for babies are scrambled or hard-boiled.

Wheat

Babies who are allergic to wheat need to avoid foods such as breads, pastas, and crackers as well as certain whole grains such as farro, rye, and barley. A wheat allergy is separate from a gluten allergy or Celiac disease. Toast and soft pasta are two wheat-based foods that are easily introduced to babies. 

Shellfish

A shellfish allergy is different from a fish allergy and includes foods such as lobster, crabs, shrimp, and mussels. Some research shows that a shellfish allergy is more common in adults than children [4]. Shellfish can be difficult to introduce to babies due to their texture. Try serving it in a puree or chopping it into bite-sized pieces once your baby is able to eat finger foods. 

Fish

A fish allergy is an allergy to finfish, not shellfish, and includes foods such as salmon, cod, whitefish, and tilapia. Fish can be introduced to babies when starting solids and may be easier to eat when made into a burger or patty. 

Tree nuts

Tree nut allergies include allergies to the following kinds of nuts: walnut, almond, hazelnut, pecan, cashew, and pistachio. Whole nuts are a choking hazard and should not be served to babies. Rather, serve as nut butter, very thinly spread on a piece of toast, or mixed thinly into oatmeal or yogurt. 

Peanuts

A peanut allergy is an allergy to peanuts and peanut products like peanut butter. It is one of the most common food allergies in kids, and for this reason, many daycare centers and schools are peanut-free. Whole peanuts and peanut pieces are choking hazards for young babies. Instead, serve peanut butter thinly spread on toast or mixed thinly into oatmeal or yogurt. 

Soy

A soy allergy includes soybeans and soybean products such as tofu. Many packaged foods contain some form of soy, so it’s important to read nutrition labels closely. When introducing soy to babies, try soft tofu. 

Sesame 

Sesame is now considered one of the top allergen foods and is required to be disclosed on nutrition labels starting in January 2023. To introduce sesame to a baby, try serving hummus made with tahini thinly spread on toast. 

Least allergenic foods for babies

A food allergy can occur with any food, but certain foods are typically low-allergenic. They include:

• Fresh or frozen vegetables

• Fresh or frozen fruits

• Meat

• Poultry

• Rice-based grain products

• Corn-based grain products

How to tell if a baby is allergic to food? Signs and symptoms

Symptoms of a food allergy range from mild to severe, and the severity of previous reactions [3] does not predict future reactions. An allergic reaction may involve the skin, the digestive system, the cardiovascular system, or the ability to breathe.

According to the American Academy of Pediatrics [7], the following are common signs and symptoms of food allergies:

How long do food allergies last in babies?

Many children outgrow food allergies during early childhood. Currently, it is estimated that 80% to 90% of egg, milk, wheat, and soy allergies [8] will go away by the time the child is 5 years old. Other allergies—such as peanuts, tree nuts, and seafood—are less likely to be outgrown.

It’s important to continue consulting your pediatrician or allergist to watch your child’s food allergies and test to see if they’ve outgrown them if necessary.

How fast do food allergies appear in babies?

Food allergy reactions are highly variable and may be different every time your baby is exposed to the trigger food. However, many reactions occur quickly after consuming the food in question.

Symptoms often appear minutes after ingestion and most commonly appear within two hours. In some rare cases, a reaction may take four to six hours or longer to appear.

Food allergies vs. food intolerance: what’s the difference?

While both a food allergy and food intolerance can cause unpleasant symptoms, there are a few major differences between the two.

First, a food allergy is caused by an immune system response and can be diagnosed with medical testing. Food intolerance does not cause an immune response and may be more difficult to diagnose. Food allergies tend to be more severe and require complete avoidance of the food whereas an intolerance may allow the person to consume small amounts.

Common examples of food intolerances are lactose intolerance and sensitivity to additives found in food.  

Celiac disease is not characterized as a food allergy or food intolerance. It is an autoimmune condition, which requires those affected to avoid gluten in their diets.

Here's a handy table to help you tell the difference:

How to test for food allergies?

If you suspect your baby has a food allergy, you should call your pediatrician right away. They will help guide you to the next steps which will likely be to see an allergist for testing.

Be prepared to answer questions about your family medical history, the symptoms your baby experienced, and how long they lasted. After that, the allergist will recommend what sort of testing, if any, is needed. 

According to the American College of Allergy, Asthma, and Immunology [9], the most common food allergy tests are: 

Skin-prick test

During a skin-prick test, a small amount of liquid containing the allergen is placed on the arm or back. Then the skin is pricked to allow the liquid to go under the skin. If a bump, similar to a mosquito bite, develops, the test is considered to be positive. 

Blood test

A blood test can be used to measure the amount of a certain antibody in the blood specific to the food being tested. It is not quite as exact as a skin test. 

Oral food challenge

An oral food challenge is considered the most accurate way to make a diagnosis, but it must be completed under medical supervision. During an oral food challenge, your baby would be fed small amounts of the suspected food and observed to see if a reaction occurs.

Since there is a risk for a severe reaction, this should NEVER be completed at home. 

Treatment of food allergies

The primary way to manage and treat a food allergy is to avoid the trigger food. Avoidance is the best method since allergic reactions are unpredictable and it’s not possible to know how your baby will respond to exposure. Your baby’s doctor may also prescribe an epi-pen in case of accidental exposure.

It is also helpful to learn how to read food labels including the different ways the food may be named or listed on the label. A registered dietitian can help you learn how to avoid certain foods and how to fill in any nutritional gaps.

How to protect your baby from food allergies?

Since the exact cause of food allergies is unknown and possibly genetic, it isn’t entirely possible to prevent them. The latest research and recommendation from the American Academy of Pediatrics [7] provides the following information for parents looking to reduce the risk of food allergies and eczema in their children. 

Exclusive breastfeeding for around 3-4 months 

The research around breastfeeding and specific food allergy prevention is inconclusive. However, evidence shows breastfeeding for 3 to 4 months reduces the development of eczema for the first two years of life and any longer duration of breastfeeding may reduce asthma throughout early childhood. Both eczema and asthma have been associated with higher food allergy risk.

No allergen restriction in mother’s diet

The report [8] found no evidence to support the restriction of the top allergen foods as a method to prevent allergies in one's diet while pregnant or breastfeeding.

Early introduction of allergens, especially peanut

There is currently no evidence to support delaying the introduction of the top allergens to prevent food allergies. In fact, it is recommended for most families to introduce them early, around 4 to 6 months. Research has found early introduction of peanuts helps prevent and reduce the risk of allergy [9] in high-risk children.

If you have a family history of food allergies or other risk factors, it’s best to talk with your pediatrician first. 

When to see a doctor

If you have a family history of food allergies or your child has a history of eczema or asthma, it is recommended to talk to your doctor prior to starting solids. They can help come up with a safe plan to introduce the top allergen foods.