Food Allergy vs. Food Intolerance - What's the Difference?

How Can I Tell if Your Baby Has a Food Intolerance or a Food Allergy

When starting first foods with your baby, you are paying attention to every possible reaction. But how do you know if a potential reaction is a food allergy or just a food intolerance?  

An intolerance to a food can often be confused with an allergy because there is an overlap in symptoms such as nausea, vomiting, cramping, and diarrhea.

In babies, and on first or second exposure, this can be even more confusing because they soil a lot of diapers, spit up a lot of food, and don’t communicate their feelings particularly well.

As we'll see, while both are considered hypersensitivities, there are a few key differences between food intolerance and allergy.


The single most important difference is that intolerances are non-immunological, whereas food allergies are based on an immune response. So one possible step to tell the difference if you suspect a reaction may be to do an allergy test.

Intolerances primarily affect the digestive system with reactions including vomiting and diarrhea.

Food allergies, on the other hand, often affect multiple organs (think lungs, skin, stomach) all at once. A true allergic reaction can be triggered by even a small exposure. Intolerance reactions can vary based on the amount of food.

Overall, 15-20% of people have food intolerances, whereas about 8% of people have food allergies.

Food Intolerance vs Food Allergy Chart - Lil Mixins

One of the tricky aspects of diagnosing food intolerance is that some people are sensitive not to the food itself but to an additive or preservative in the food, or an ingredient used in the preparation of the food. That’s not the case with a food allergy so different brands, washing techniques, or preparations won’t make a difference in food allergies. (Here's an important caveat on preparation affecting egg allergies)

What Does this Mean for Your Baby?

If you notice that your child frequently vomits or has diarrhea, the best advice we received is to start a food diary. If you are confused about the line between spit-up and vomit, talk to your pediatrician. They may say something fun like “vomit has to project.”

Unfortunately, there are a no tests that are clinically useful in identifying of the source of food intolerances, though there are companies out there trying. Your pediatrician may recommend an elimination diet wherein you try to avoid the culprit foods and see if things get better. If baby is still breastfeeding, mom may also try to eliminate certain foods, though that will only help sometimes.

When Should You Call the Doctor or Go to the ER?

The rule of thumb that our allergist gave us is that you use the epinephrine, and go to ER if there is any difficulty breathing, symptoms are particularly severe, such as loss of consciousness, or if more than one body system seems involved (i.e. hives and vomiting). Remember that if you give epinephrine, you still have to go to the ER because symptoms can come back.

As the parent, you should trust your instincts. This goes for all parental concerns, not just reactions to foods. Pediatricians are your partner, so if anything seems off always call your doctor. They may be able to advise you over the phone, allay your fears, or encourage you to come in for an office visit.



Lil Mixins is the #1 selling Infant Peanut Powder and Infant Egg Powder, helping moms around the country start early introduction of peanuts and other allergens to their infants and babies.

Learn more about food allergies and your child on our About Page, in our Parent Resource Center, and our FAQ

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