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The Most Common Food Allergies in Babies

February 02, 2021 6 min read

Sharing new foods with your baby is an exciting and monumental experience. All too often this amazingly joyful time can be damped by by anxiety, questions, and fears about food allergies. 

We get why. The prevalence of food allergies has increased dramatically in the last decade, doubling for some foods and even tripling for others. Today, nearly 1 in 13 children in the U.S. have a food allergy. So if you are feeling uncertain, you are not alone.

Any food has the potential to cause an allergic reaction and so far, over 160 foods have been identified.

However, eggs, milk, peanuts, wheat, soy, tree nuts, fish, shellfish, and sesame are responsible for 90% of all food allergies and are the most common amongst children and babies.

We’re breaking down what they are, what you should know, and what you can do to best introduce these foods before they become allergies.  


Onset of peanut allergies typically appears in a child’s formative years and is usually a lifelong disorder. However, up to 22% of children will find that this allergy resolves itself as they age into their teenage years. 

Manifestations of peanut allergy range from mild to severe and peanut allergy is one of the most common causes of severe allergy attacks, even from digesting just a trace amount of the protein.

For individuals who have developed peanut allergies, when you eat peanuts or any food containing peanuts, your immune system identifies it as a harmful protein. It then overreacts, causing symptoms such as stomach aches, itching, swelling, and even life-threatening reactions like anaphylaxis. 

Differing from tree nuts, peanuts grow underground and are considered legumes, but it is important to note that less than 7% of food allergies develop to peanuts alone. Many children who develop peanut allergies are at a higher risk of developing tree nut and other food allergies, so be sure to speak to your pediatrician. 

Learn more about how to introduce peanuts to your baby.

Tree Nuts

Unlike peanuts that grow underground, tree nuts grow on trees and include nuts like almonds, cashews, hazelnuts, pecans, pistachios, and walnuts.

 Affecting around 2% of the population, tree nut allergies are one of the most common foods causing acute allergic reactions and can be associated with severe allergic reactions like anaphylaxis. Individuals who are allergic, as well as a parent or caretaker, should carry an epi-pen with them at all times. 

If your child is allergic to one type of tree nut, that doesn’t necessarily mean that they will be allergic to all tree nuts, or even peanuts. However, there is a high chance that they will be allergic to multiple, closely related types, like walnuts and pecans. 

It may be possible to avoid certain types and still be appropriate and safe to consume others. At the end of the day, it’s important to work with your pediatrician to discover the best approach to tree nuts for an allergic child. 

Though tree nut allergies generally start in childhood and persist through life, studies show that up to 14% of individuals may outgrow tree nut allergies over time.

Learn more about how to introduce tree nuts to your baby.


Cow’s milk is one of the most common causes of food allergies, especially in young children. While up to 20% of children may outgrow this allergy by age four, some will remain allergic into adulthood.

A milk allergy can cause a range of symptoms in babies, from mild to severe. Unlike other allergies, a reaction to milk can include a colicky, fussy baby, blood in the stool, and signs of poor growth, as well as more traditional signs of an allergy, like hives or even anaphylaxis. 

A true milk allergy will differ from milk intolerance, or intolerance to lactose. Intolerance doesn’t involve the immune system, rather causing reactions like indigestion, bloating, or gas. An allergy, however, is in reaction to one or both of the proteins in milk - casein or whey. 

Though cow’s milk is the usual cause of a milk allergy, children can also react to milk from other mammals like sheep, goats, or buffalos. Individuals who are allergic to cow’s milk may also be allergic to soy milk, but it is less likely. 

See our guide to introducing cow's milk to your baby.


Another very common food allergy in babies and toddlers is egg and affects about 2% of young children. Signs of an egg allergy can include stomach aches, respiratory problems, hives or rashes, and in extreme cases, anaphylaxis.

Though the proteins that trigger an allergy are in the egg whites, some children can have intolerances to either the yolks or the whites and not necessarily both. While it is one of the most common allergies, research shows that 68% of children who have developed an egg allergy will outgrow it by the time they are 16 years old.

If your child has developed an egg allergy, that does not mean that all egg products must be avoided. Studies have shown that cooked eggs change the shape of the allergy-inducing proteins, making your body less likely to identify them as harmful and trigger a reaction. However, you should not introduce any egg-containing foods without first speaking to your pediatrician. 

Checkout our guide to introducing eggs to your baby for more information. 


“Shellfish” is a term for marine animal species mollusks, crustaceans, and echinoderms. It includes seafood such as shrimp, crayfish, crab, lobster, clams, scallops, oysters, and mussels. 

Though some individuals who develop a shellfish allergy may react to all shellfish, others may only develop an allergic reaction to one or two. Reactions can range from mild to severe, with symptoms like hives, swelling, a stuffy nose, and even anaphylaxis. 

Shellfish allergies can actually develop at any age but are often more common in adults, rather than infants. Even so, the 2020 USDA Dietary Guidelines recommend introducing your baby to commonly allergenic foods like peanuts, egg, cow milk products, tree nuts, wheat, crustacean shellfish, fish, and soy at 4-6 months.

Learn more about how to introduce shellfish to your baby.


Including common allergenic seafood like cod and salmon, fish allergies can affect up to 2% of the general population. Similar to shellfish, fish allergies usually develop later in life, with 40% of those developing a fish allergy in adulthood.

If you or your child has developed a fish allergy, that does not necessarily mean you will be allergic to shellfish and vice versa. Shellfish and fish don’t carry the same proteins that cause allergic reactions. However, many people who do develop a fish allergy may be allergic to more types of fish

A fish allergy can also have similar symptoms as a reaction to bacteria, viruses, toxins, or other contaminants in the fish. If you believe you or your child has developed a fish allergy, speak to your doctor or pediatrician. 

When introducing fish into your child’s diet, be sure to adhere to AAP guidelines that children should not eat more than 12 ounces of fish a week due to concerns about traces of mercury.

See our guide to introducing fish to your baby.


Oats and wheat are some of the most common allergy-inducing grains. You may develop an allergy to one type of grain without necessarily developing an allergy to other types of grains, though it is more likely that you will. 

Often confused with celiac disease and gluten sensitivity, a grain allergy occurs when your immune system overreacts to proteins found in wheat, while celiac disease is an autoimmune disease that leads to a lack of digesting enzymes in the gut for wheat. 

In celiac disease, you can suffer from weight loss, digestive distress, and other symptoms as you lack the enzymes you need to absorb or process wheat. Alternatively, a grain allergy will result in reactions such as hives, vomiting, or swelling, and in severe cases, anaphylaxis. 

Grains are not only very prominent in food, but also in other household products, like cosmetics and bath products, so it is important to be cautious and proactively read ingredient labels if your child develops a grain allergy.

Checkout our guide to introducing grains to your baby for more information.


Triggered by a protein in soybeans or soybean-containing products, only around 0.4% of infants will develop a soy allergy, and 70% of children who develop this allergy will outgrow it while aging. 

Normally, allergic reaction symptoms will include itchiness and swelling, and only in the rarest of cases can this turn into anaphylaxis. 

Children with a milk allergy will often turn to soy as a nutritionally complete substitution, but unfortunately, some children with a milk allergy will also develop an allergy to soy, and you should consult with a pediatrician first.

Learn more about how to introduce soy to your baby.


Sesame allergies have been increasing over time and are more common than first perceived, affecting more than a million children and adults.

Sesame is very prevalent in everyday foods and can be difficult to avoid as it’s not currently required on food labels. Only the top 8 allergy-inducing foods, as listed above, are currently required on food labels, making sesame a hidden, and often dangerous, ingredient. It's often listed under “spices” on the ingredient label. 

Depending on the child, reactions range from mild to severe, with symptoms such as difficulty breathing, hives, itchiness, and more. 

See our guide to introducing sesame to your baby.

Pediatricians and experts now recommend starting a food allergy introduction routine between 4-6 months. The Bottom Line: Don't leave allergen introduction to chance.