Yes, babies can and do get allergies, and they’re more common than many parents expect. An estimated 8% of children in the United States have food allergies, and roughly 45% of infants who develop the skin condition eczema show symptoms before they’re 6 months old. Allergies in babies look different from allergies in older kids and adults, which makes them easy to miss or confuse with other conditions.
When Allergies Typically Appear
The first allergies to show up in a baby’s life are usually food allergies and eczema, often appearing together in the first year. This pairing isn’t a coincidence. When a baby’s skin barrier is compromised by eczema, food proteins from the environment can enter through the skin and trigger the immune system to treat those foods as threats. Research published in JAMA Network Open found that eczema in infancy is most strongly associated with food allergy, suggesting that early skin barrier damage plays a direct role in how food sensitivities develop.
Seasonal allergies to pollen, grass, and mold are a different story. Babies almost never get them. The immune system needs multiple seasons of exposure to pollen before it can develop a true allergic response, so seasonal allergies rarely appear before age 3 or 4. If your baby has a stuffy nose in the spring, a viral infection or dry indoor air is far more likely than hay fever. The exception: children with severe eczema or asthma may occasionally develop seasonal allergies a bit earlier.
The “Allergic March” in Childhood
Pediatric allergists describe a pattern called the allergic march, where one type of allergy tends to lead to another over time. It typically starts with eczema and food allergy in infancy, then progresses to respiratory allergies like asthma and hay fever between ages 3 and 6. Not every child follows this path, but studies show a clear relationship: infants with egg allergy, for example, face a higher risk of developing respiratory allergies by age 4. Children who have persistent eczema throughout childhood are at risk for all three, food allergy, asthma, and allergic rhinitis, likely because ongoing inflammation at the skin barrier keeps the immune system in a heightened state.
Family History and Risk
Genetics play a significant role. If one parent has allergies, a child’s risk of developing allergic sensitization increases by roughly 18 to 26%, depending on which parent is affected. Maternal allergy history carries a slightly higher risk than paternal history. When both parents have asthma specifically, the child’s risk of developing asthma jumps to about three times the baseline, regardless of whether the child is a boy or girl.
That said, babies with no family history of allergies can still develop them. Family history raises the odds, but it’s not the only factor.
Common Food Triggers
Nine foods account for the vast majority of allergic reactions in children: milk, eggs, peanuts, tree nuts (like almonds, walnuts, and pecans), wheat, soy, fish, shellfish, and sesame. Milk and eggs are the most common culprits in infants specifically, partly because they tend to be among the first foods babies encounter.
Two Types of Allergic Reactions in Babies
Not all food allergies behave the same way. The type most people think of, where hives or swelling appear within minutes of eating a food, is driven by a specific immune pathway involving IgE antibodies. These reactions cause symptoms like hives, itching, swelling, wheezing, and in severe cases, anaphylaxis. They tend to happen quickly, usually within minutes to two hours of exposure.
The second type involves a different part of the immune system and primarily affects the gut. The most well-known version is called FPIES (food protein-induced enterocolitis syndrome), and it looks very different. Instead of hives, babies with FPIES experience repeated vomiting, diarrhea, and sometimes dehydration, usually a few hours after eating the trigger food. Because these symptoms overlap with stomach bugs and reflux, FPIES often goes undiagnosed for a while. It’s most common in infants and tends to resolve in early childhood.
Allergy vs. Cold: Telling Them Apart
Babies get so many colds in their first year that it’s hard to know when symptoms point to something else. Both allergies and colds can cause sneezing, a runny nose, congestion, and coughing. The key differences: colds usually come with a fever and resolve within 7 to 10 days. Allergies don’t cause fever but do cause itchiness, particularly in the eyes, ears, nose, and throat. If your baby is constantly rubbing their eyes, trying to clear their throat, and the symptoms drag on for weeks without a fever while they’re still playful and eating normally, allergies are a more likely explanation.
Recognizing Severe Reactions in Babies
Anaphylaxis in infants is particularly tricky to spot because the warning signs can look like normal baby behavior. Drooling, spitting up, loose stools, fussiness, and drowsiness are all things healthy babies do regularly, but they can also be signs of a serious allergic reaction. Infants with anaphylaxis are more likely than older children to present with hives, wheezing, and vomiting, and less likely to show the respiratory distress that adults associate with severe reactions.
One study of food-allergic reactions in children found that 10.3% of infants experienced anaphylaxis, more than double the 4.7% rate in the overall group. The combination of hives spreading across the body, vomiting, and sudden lethargy after eating a new food warrants immediate medical attention.
Early Introduction as Prevention
Guidelines on when to introduce allergenic foods have shifted dramatically. The old advice to delay peanuts, eggs, and other common allergens until age 2 or 3 has been replaced by evidence that early introduction actually reduces allergy risk. Current guidelines from the National Institute of Allergy and Infectious Diseases recommend the following approach based on a baby’s risk level:
- High-risk infants (those with severe eczema, egg allergy, or both): Introduce peanut-containing foods as early as 4 to 6 months, after the baby has tolerated other solid foods. These babies may need allergy testing first to determine the safest way to introduce peanut.
- Moderate-risk infants (mild to moderate eczema): Introduce peanut-containing foods around 6 months, based on family preferences. No prior testing is needed.
- Low-risk infants (no eczema or existing food allergies): Introduce allergenic foods freely as part of normal dietary progression.
For high-risk babies who begin eating peanut foods early, the recommendation is to keep it consistent: roughly 6 to 7 grams of peanut protein per week, spread across three or more feedings. This isn’t a one-time introduction. Regular, sustained exposure is what trains the immune system to tolerate the food.
How Allergies Are Tested in Babies
Allergy testing in infants is possible but comes with important limitations. Skin prick tests and blood tests that measure allergen-specific immune markers both detect sensitization, meaning the immune system has flagged a substance. But sensitization doesn’t always equal a true allergy. A baby can test positive for sensitivity to a food they eat without any problems. That’s why test results always need to be interpreted alongside the baby’s actual symptoms and feeding history, not in isolation. A positive test without symptoms doesn’t necessarily mean a food needs to be avoided, and over-restricting a baby’s diet based on test results alone can do more harm than good.