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What Are Food Allergies?

Food allergies seem to be increasing. I have them, and chances are you know someone who has them as well. Food allergies seem to be everywhere. You're seeing everything peanut-free or dairy-free or gluten-free, or soy-free.

What exactly is a food allergy, and how is it different from just an intolerance? An intolerance means your child can still eat it. They just may have some feelings where they just don't react very well to it, but it's not a true allergy.

A true food allergy is actually an immune system reaction to the food. About 5% of children have true allergic reactions to food, and you will know that your child has a food allergy if the symptoms happen within two hours of eating certain foods.

Recognizing the Symptoms of a Food Allergy

Some common food allergy symptoms include swelling or itching of the lips, tongue, or mouth, and that's commonly called oral allergy symptoms. If your child has stomach cramps, diarrhea, vomiting, hives, difficulty breathing, wheezing, or coughing to the point where they look like they're struggling to breathe, those are true allergies.

And some children have severe allergic reactions called anaphylaxis. Those reactions usually happen within minutes to two hours after contact with the food that causes the reaction, and they can cause significant trouble breathing, trouble swallowing, weakness from a sudden fall in blood pressure known as shock, or just being very confused and out of it because their whole body is just attacking the food that they just took in. Quite often, you can also have food-induced asthma attacks that are anaphylaxis.

Risk Factors of a Food Allergy

The tendency to be allergic to certain foods is inherited. If both parents have allergies, the chances of a food allergy rise to about 75% for each child, and often a child is allergic to the same food or foods as the parents or siblings.

Children who have other allergic conditions, such as eczema, asthma, or allergies in general, they're more likely to have food allergies than those who do not have allergies or what we call atopic conditions, which means your body is more sensitive to what it considers a foreign substance than somebody else's.

Top Food Allergens to Watch For

What are the most common food allergies? Well, pretty much the most common one we know of is peanuts. We see that quite a lot. And also cow's milk, eggs, soybeans, and wheat account for over 80% of food reactions. Fish, shellfish, and tree nuts also top the list.

At least half of the children who develop a food allergy in their first year of life outgrow it by the time they're two or three years old. But sometimes those food allergies, specifically those for, like, milk or soy, those are more outgrown than others, but peanut allergy, nuts, fish, shellfish, they often last a lifetime.

Tracking Reactions and Diagnosing Food Allergies

How can you help your physician determine if your child is allergic to a certain food or not? Keep a diary of symptoms and recently eaten foods. If you already know what food is causing an allergic reaction, then make sure your child stops eating that food for about two weeks.

If you don't know what the food is, keep a diary so that you can write down what food your child has and if they had a reaction or not. Usually, this is best when you're introducing new foods in their first year or two of life.

If you know that your child has a suspected food allergy, you might be referred to an allergist's office. Some food allergies can be determined by a blood test, but others cannot. And if you think your child has a food allergy, ask your doctor for that blood test. If none is available, your child would be referred to an allergist's office.

They can do what's called a food challenge, and that's where, in the office, the allergist will actually watch your child eat the food that they are allergic to and monitor for a reaction. It has to be done in an allergist's office because of the concern for a severe, life-threatening reaction.

Managing Food Allergies Safely

How are food allergies treated? Avoidance. Unfortunately, there are no allergy shots or medications that can prevent you from having an allergic reaction to a particular food. You need to keep your child free of the foods that you have found them to be sensitive to. If they do come in contact with those foods, make sure they have an antihistamine such as Benadryl, Claritin, or Zyrtec that they can have handy to help calm down the allergic reaction.

If your child has a severe allergy, these are the anaphylactic reactions that I mentioned; your child must have an EpiPen. That is epinephrine that can be injected into their thighs, which can help stop an allergic reaction. If your child has an allergic reaction and they use the epinephrine, you need to call 911 to have your child transported to the nearest emergency room for monitoring after the shot is given.

Can Food Allergies Be Prevented?

Many people ask me, "Can I prevent food allergies in my child?" There is no real way to prevent food allergies because the tendency is inherited. And recent studies have shown that delaying the introduction of high-risk foods such as eggs, fish, or peanut butter does not reduce the risk of becoming allergic to that food.

Exclusive breastfeeding in the early months is helpful in preventing atopic dermatitis, but restricting the mother's diet from certain foods, unfortunately, has not been shown to be helpful either. We always recommend that there is no solid food be given to babies before four months old.

Preparing for School and Public Settings with Food Allergies

What should I do for my child who has a food allergy when they enter school? If your child is in day care or school, you will need to let them know that your child has a food allergy and have a plan in place for if your child is exposed to those foods.

Make sure they have an EpiPen if they have a severe allergic reaction. Make sure they have Benadryl if it's a milder reaction. Make sure the school knows that your child has this allergy so they can work with you.

Many schools have peanut-free programs, so that your child may not be allowed to have peanuts in the facility at all, or they would be moved to a table other than where food is being served. I see this mostly with peanuts.

But the most important thing is to keep an open line of communication so that your child's school or day care knows exactly what to do in the case that your child has been exposed to one of these foods they are sensitive to.

While food allergies can be inconvenient and make it difficult to plan meals and parties and everything, remember your child or someone else's child's life is at stake if you serve them something that they are allergic to. So make sure you are aware of food allergies, no matter where you go.

_{updated: August 6, 2025
originally published: November 10, 2014}