At around 6 months old, your baby is ready to begin eating solid food—what a wonderful new journey for both of you. As your baby experiences a whole new world of flavors and textures, you may notice there are certain foods she reacts to differently—and we don't mean spitting out the pureed spinach! In certain cases, she may be reacting to a food allergy. Read on to learn what exactly a food allergy is, what some common food allergies are, and what to do if your baby has an allergic reaction.

What Are Food Allergies?

An allergy is the immune system's response to something it doesn't like. For example, some people are allergic to dust or pollen and get itchy eyes or a runny nose when exposed to these allergens. With food allergies, most people react with digestive problems, hives, or breathing problems.

The human body treats allergens as invaders and produces antibodies to try to fight off the invasion. Once these antibodies enter the bloodstream, the body reacts—hence the term "allergic reaction," which you can read about more here.

Thankfully, food allergies are rare in children, with fewer than 8 percent of those under the age of 3 having them. Many of these children also outgrow their food allergies over time.

Still, because the body’s reaction can be severe if your baby does indeed have a food allergy, it’s important to know what an allergic reaction can look like and what to do if you suspect your baby has a food allergy.

Signs and Symptoms to Look Out For

Food allergies can be more serious than seasonal allergies because the body’s reaction can be more severe.

Here are some of the signs and symptoms of a food allergy in a baby or toddler:

  • Skin rashes. You might notice red, itchy, or even swollen patches.

  • Breathing problems. These can range from sneezing to reactions that are a bit more serious like wheezing or throat tightness.

  • Stomach symptoms. These can include vomiting and diarrhea.

  • Circulation problems. You might notice that your baby has pale skin or has a dizzy spell. In serious cases, your little one may become unconscious.

Notify your child's healthcare provider if you see any of these symptoms. If multiple symptoms happen quickly at the same time after your baby or toddler has eaten a food, she may be having an anaphylactic reaction (a very serious allergic reaction that comes on quickly), which is life-threatening. Seek immediate medical attention by calling 911.

Common Foods That Cause Allergic Reactions

So what are the most common food allergens? Here's a list of foods that often trigger an allergy in your baby or toddler:

  • Cow's milk. About 2 or 3 percent of children have milk allergies; many children outgrow this allergy. Note that most baby formulas are made with cow's milk, so if you're formula-feeding and your infant is allergic to milk, you may have to switch to a hypoallergenic formula. If you're breastfeeding and your infant is allergic to milk, you may have to follow a milk-free or dairy-free diet.

  • Eggs. Most children outgrow this food allergy.

  • Tree nuts (almonds, cashews, hazelnuts, pecans, pistachios, and walnuts). Most children do not outgrow tree nut allergies.

  • Peanuts. These are not actually nuts; rather, they are legumes similar to beans and peas. Most children do not outgrow their peanut allergy.

  • Soy. This allergy is more common in babies than in older children. Some children do outgrow this allergy.

  • Wheat. An allergy to wheat is different than a sensitivity to gluten (which is also found in rye and barley—not just in wheat). A wheat allergy can cause a serious allergic reaction, whereas a gluten sensitivity wouldn't. Many children outgrow a wheat allergy.

  • Fish (cod, salmon, tuna, etc.). This food allergy usually lasts into adulthood.

  • Shellfish (shrimp, clams, scallops, lobster, etc.). This food allergy usually lasts into adulthood.

As you can see, there is a bright side to some of this: Many children outgrow their food allergies, with an estimated 80 to 90 percent of children growing out of their allergies to milk, eggs, wheat, and soy by the time they are 5 years old. And, one in five children will probably outgrow peanut allergies.

Speak to your baby's healthcare provider if you have any questions about your little one's food allergy.

What's the Difference Between a Food Allergy and a Food Intolerance?

Sometimes children aren't allergic to a certain food, but instead have an intolerance for it. Intolerance of certain foods (basically an inability to digest the food) is less serious than a food allergy (which can result in a very serious allergic reaction) but it's still an uncomfortable problem.

Here are two common food intolerances:

  • Lactose intolerance. This is when your child has difficulty digesting the natural sugar in milk. It is the most common food intolerance and leads to symptoms like gas, bloating, and diarrhea. This intolerance usually shows up around 3 years of age and lasts into adulthood.

  • Gluten intolerance. This is when the body is unable to digest a protein (called gluten) found in wheat, rye, and barley. Because the intestines are unable to absorb the nutrients from these foods, an immune reaction occurs, with symptoms such as cramps, diarrhea, weight loss, and irritability. A gluten intolerance is typically diagnosed between the ages of 6 months and 2 years, and it lasts into adulthood.

How Are Food Allergies Diagnosed?

If you suspect your baby has an allergy or intolerance, consult her healthcare provider. It's not a good idea to try to make your own diagnosis. The healthcare provider may use any of the following to diagnose a food allergy:

  • Skin prick test (scratch test). This involves placing a drop of the allergen in a liquid extract form on your baby's skin, and scratching the skin to see if there is a reaction. Results show up in about 15 minutes.

  • Blood test. This can be done to measure the amount of antibodies in your baby's blood. The sample of blood is tested in a laboratory by mixing it with different allergens in liquid extract form to see if antibodies are detected. You may have to wait a few weeks to get these results.

  • Elimination diet. This involves removing the suspected food allergen from your baby's diet and seeing if her symptoms clear up over time. You'll have to monitor your baby to see if the symptoms do clear up and document the process for several weeks.

What to Do If Your Baby Has Been Diagnosed With a Food Allergy

If your baby or toddler is diagnosed with a food allergy, it's best to begin avoiding that specific food immediately, even if her allergic reaction isn't a serious one. You'll need to be very mindful of what foods your baby or toddler is going to eat at all times, especially if it's food you didn't prepare.

Check Ingredient Labels

Be aware that many store-bought foods contain traces of allergens (the most common ones in packaged foods are tree nuts, peanuts, soy, and wheat), so you will need to start reading all product labels to make sure you aren't accidentally giving your baby or toddler something he may have an allergic reaction to.

It's also a good idea to make sure your pantry doesn't contain any foods that have traces of the allergen, because you never know when your curious toddler may get into something he shouldn't be eating.

In time, when your child is old enough to understand, you'll want to teach him about his food allergy.

Pay Attention to Your Infant's Reactions

If you're still in the breastfeeding stage, you may want to avoid certain foods if you see your infant having a bad allergic reaction like skin rashes or loose stools. But check with his healthcare provider first before making any sweeping dietary changes.

Similarly, if you're formula-feeding, you will want to pay attention the list of ingredients on the formula label if you see your infant experiencing rashes or loose stools. He may be allergic to one of the ingredients. Check with his provider, who may recommend switching to a hypoallergenic formula.

Of course, you'll need to watch carefully for signs of food allergies as you transition to feeding your little one solid foods.

Precautions to Take With Serious Food Allergies

If your child's healthcare provider has diagnosed a serious food allergy that results in life-threatening anaphylaxis, he will prescribe a special epinephrine auto-injector. Epinephrine is a life-saving drug that works quickly to stop swelling of the airways.

You’ll need to learn how to use the device so that you can inject it immediately in case your little one experiences an anaphylactic reaction.

Keep a number of these devices handy, perhaps keeping one in your car and one at home in your first-aid kit or medicine cabinet. If your baby goes to daycare, make sure the staff has one as well.

You’ll also need to make sure everyone who cares for your little one (including grandparents and babysitters) knows how to use the injector, and you'll need to remember to replace the injectors when they expire.

Caregivers, daycare staff, preschool teachers, and friends and family members who care for your baby or toddler should all be aware of his allergies and know what to do if an anaphylactic reaction occurs.

FREQUENTLY ASKED QUESTIONS

  • The foods that babies and toddlers are most commonly allergic to include:
    • Cow's milk
    • Eggs
    • Tree nuts
    • Peanuts
    • Soy
    • Wheat
    • Fish
    • Shellfish.
  • If your baby or toddler is highly allergic to a food it may trigger anaphylaxis, which requires an injection of epinephrine via a device called an epinephrine auto-injector. You'll need a prescription from your baby's healthcare provider. Have this device nearby at all times in case your baby has a severe allergic reaction.

    In less severe cases, make note of your child's allergic reaction and the food that may have triggered it, and speak with your child's healthcare provider about a recommended course of action, which may include removing the food entirely from your child's diet.
  • Yes, one of the most common allergic reactions to a milk allergy is a rash. The rash can look like eczema or hives. The skin may also become itchy and swell. Other common symptoms of a cow’s milk allergy include vomiting and diarrhea.

If your baby or toddler is diagnosed with a food allergy, it may mean avoiding that food altogether, and making sure that everyone around him is prepared for the possibility of immediate action if he has a severe allergic reaction.

Luckily, many food allergies are outgrown by school age, and those that aren’t can be managed by being extra vigilant of what your little one eats or has access to. If you need help with how to manage your child’s food allergy or have any other questions, don't be afraid to turn to his healthcare provider for guidance.

How We Wrote This Article The information in this article is based on the expert advice found in trusted medical and government sources, such as the American Academy of Pediatrics and the American College of Obstetricians and Gynecologists. You can find a full list of sources used for this article below. The content on this page should not replace professional medical advice. Always consult medical professionals for full diagnosis and treatment.