4 Types of Common Food Allergies in Babies: A Parent's Guide

It’s no secret that food allergies, especially amongst babies and children, are on the rise. In fact, according to the Centers for Disease Control and Prevention, food allergies now affect 8%—or 1 in 13 children—in the United States today. Sadly, that number seems to grow each year. Without clear solutions, parents often feel hopeless and alone. 

The problem is, common food allergies in babies are a little more complicated than you might expect. And typically, they’re actually the second step of a process called the atopic march, which begins with atopic eczema and then cascades into food allergies, and asthma. 

In order to be empowered and take control of your baby’s health, it’s important to first understand that there are four different types of food allergies that show up in babies. Sometimes, what looks like a food allergy is actually a food intolerance. Let’s dive into each type and what they mean for your child's health.

Understanding the four types of food allergies in babies

Immune-mediated food reactions, also called allergies, include:

1. IgE mediated: For example, hives 
2. Non-IgE mediated: This includes a vomiting disorder known as EoE (eosinophilic esophagitis) and celiac disease, an autoimmune condition triggered by gluten 
3. Mixed IgE and non-IgE mediated: For example, a type of eczema often seen in babies known as atopic dermatitis
4. Cell mediated: For example, a contact rash 

During an IgE-mediated reaction, the immune system mistakes an allergen as a real threat and releases immunoglobulin (IgE), which then triggers other immune cells to react. This occurs quickly and can be very serious. 

A non-IgE-mediated allergy may develop more gradually in response to allergen exposure. Symptoms can show up in the digestive tract or the skin. Examples include food protein-induced enterocolitis syndrome (FPIES) and eosinophilic esophagitis (EoE). Little ones with these conditions may struggle with weight gain. 

Non-immune mediated food reactions—which can be mistaken for food allergies—include food intolerances. A common food intolerance is lactose intolerance.

The top food allergies in babies

As we mentioned above, food allergies are growing at an alarming rate! It was recently estimated that food allergies affect 3% of babies under one year old, up to 8% of children, and 3% of adults in industrialized countries [1], [2].

The top eight food allergens are:

• Peanuts (the most common) [3]
• Tree nuts, such as walnuts or almonds
• Cow’s milk
• Eggs
• Wheat
• Soy
• Fish
• Shellfish

Common food allergies in babies often follow eczema and later progress into allergic rhinitis or asthma—the atopic march. In fact, when babies are diagnosed with eczema within their first year, they’re also 11 times more likely to develop peanut allergies during that same year [4].

Research suggests that the appearance of food allergies in babies involves genetics, diet, and baby gut health.

For example, changes in the baby gut microbiome—or the bacteria that live in the gut—have been found in those with different types of food allergies, including egg, peanut, soy, wheat, or cow milk.

Tiny Health baby gut tests look for biomarkers linked to food allergy development to better understand if infants harbor the bacteria that protect against food allergies.

What are the signs of food allergy in a baby?

Food allergies are an immune system reaction that shows up soon after eating an allergen or trigger food. Sometimes even a small amount of food can be responsible for a major reaction.

Signs of food allergy in a baby can range from:

• Digestive troubles 
• Hives or itchiness
• Swollen airways 
• Anaphylaxis, a severe allergic reaction that’s life-threatening

Typically, when you notice signs of food allergies in babies, the immune system mistakes an allergen as a real threat and releases IgE, or immunoglobulin E. IgE then signals other immune cells, causing symptoms of food allergy.

Cow milk protein allergy in babies

Cow milk protein allergy is one of the earliest and most common food allergies in babies. It affects 3-7% of babies and usually shows up within a baby’s first year. 

Fortunately, 75% of kids outgrow cow milk allergy by the time they’re three years old [5].

While there is no diagnostic test for cow milk protein allergy, like a blood or skin prick test, you may notice signs of cow milk protein allergy within the first week of your baby’s exposure to cow’s milk. This can include:

• Digestive troubles, like gas or diarrhea
• Rash or eczema that does not improve
• Hay fever-like symptoms
• Blood or mucus in the stool

Some babies are more sensitive to milk protein (and have more severe symptoms) than others.

Even though breastfeeding seems to protect babies against the development of cow milk protein allergy, a baby may still react to cow’s milk protein in a mother’s diet. In this case, it’s still ideal for a mother to continue breastfeeding. However, it may help to try a dairy-free diet or work with a practitioner to avoid both obvious and hidden sources of cow milk protein. It can take up to 72 hours for a mother's breastmilk to become free of milk protein.  

When using formula, cow milk protein allergy can be especially tricky since many formulas are made with cow’s milk. With the support of your healthcare provider, you may want to consider:

• Starting with a formula made from broken-down proteins, also called hydrolyzed formulas, because these eliminate symptoms in 90% of children.
• An amino acid formula if signs of allergy do not improve.
• Steering clear of soy-based, goat and sheep milk formulas, since roughly 30% of babies tend to have the same reaction to these as they do to cow milk.

Cow milk protein allergy is especially noteworthy within a baby’s first year because it increases the risk of other atopic conditions, like eczema, and other chronic immune-mediated disorders such as inflammatory bowel disease [6].

Milk allergy in babies may have a microbiome connection

There seems to be a relationship between milk allergy in babies and baby gut health.

For example, we know that high levels of certain friendly bacteria—like some Clostridia and Firmicutes—at the age of 3 to 6 months is associated with the resolution of milk allergy by the time a child is 8 years old [7].

Likewise, interesting research has been done with germ-free mice, which have no bacteria living in or on them. When the gut bacteria from babies with cow milk protein allergy are placed in germ-free mice, these mice seem more vulnerable to a strong, anaphylactic response to cow's milk protein [8]. Germ-free mice with bacteria from allergy-free babies, on the other hand, are protected from cow milk allergy. 

We also see a connection between interventions that impact the microbiome and food allergy. 

Research suggests that babies born by C-section delivery have more than double the risk of developing food allergies and asthma later in life [9]. What’s more, antibiotic use early in life— specifically penicillin—also appears to increase the risk of developing milk and non-milk (such as nuts and seafood) allergies [10].

This implies that while food allergies are probably driven by factors like genetics and diet, there are also some notable differences in the gut microbiome of folks with different types of food allergies.

That said, research currently lacks consistency. So it’s tough to interpret what these differences really mean. However, it suggests that baby gut health and the baby microbiome are potentially important in regulating a baby’s response to food allergens. 

At Tiny Health, we’re excited to bring your family the latest microbiome research and work with a team of expert scientists to help protect your baby from allergies.

Non-IgE-mediated food allergies in babies

Non-IgE food allergy is an umbrella term for several conditions. The one thing that unites them all is inflammation of the gut.

On the whole, these conditions are rare. But when they do occur, the most common non-IgE food allergies are:

• Eosinophilic esophagitis (EoE)
• Food protein-induced enteropathy (FPE)
• Food protein-induced enterocolitis syndrome (FPIES)
• Food protein-induced allergic proctocolitis (FPIAP)

When it comes to non-IgE food allergies, we see a relationship with baby gut health there too.

For example, we know that FPIES is more common in babies who have been exposed to antibiotics during pregnancy and infancy, increasing their levels of unfriendly bacteria [11].

Cow milk FPIES is more likely to show up in babies born by C-section delivery than those born by vaginal delivery [12].

FPIAP is rare and defined by bloody stool. The response is often triggered by cow’s milk protein and it tends to show up in babies under 12 months old.

When addressing FPIAP, probiotic formulas that include Lactobacillus rhamnosus GG may be useful [13]. If fecal microbiota transplantation is an option that’s available, research has found that this type of therapy can relieve symptoms of FPIAP within days with no relapse over the following 15 months [14].

The difference between food intolerance and food allergy

Food intolerance is not an allergy because it does not involve a response from your baby’s immune system. That said, the signs of food intolerance are very similar to food allergy. They include:

• Nausea
• Vomiting 
• Cramping

Food intolerance can show up if your baby doesn’t have the enzymes needed to digest a particular food. For example, lactose intolerance shows up when there isn’t enough lactase enzyme in the small intestine to digest the milk sugar, lactose. While many adults are lactose intolerant, babies make plenty of lactase in order to digest breastmilk.

Other causes of food intolerance include:‍

• Sensitivity to food additives
• Food poisoning
• Histamine toxicity caused by some kinds of fish including tuna, mackerel, anchovy, and herring

If you suspect lactose intolerance is an issue for your baby, it’s worth pointing out that this is very rare in children under the age of 5 years old. You’re more likely to see an immune-mediated reaction in a baby than a food intolerance.

Common food allergies and food sensitivities in babies

How baby gut health testing can show the full picture 

Food allergies in babies have a strong relationship to gut health, especially in the critical first 1000 days of life when a baby’s microbiome is changing rapidly. We have a small window of time when we can make a difference, and potentially even change the trajectory of a baby’s immune development.

At Tiny Health, we take a close look at the bacteria in a baby’s gut and take a functional approach to food allergies and sensitivities. While gut microbiome testing cannot diagnose a food allergy or lactose intolerance, it can give you a clear snapshot of the environment that’s impacting your baby’s immune development. 

We want to see a lot more good bacteria than unfriendly ones because typically these good bacteria create helpful compounds that are soothing and supportive to your baby’s immune system. 

As Tiny Health distills the latest research about baby gut health, we’re excited to share what we learn with parents to support you in reducing future illness.

‍