Food Allergy vs. Intolerance: Knowing the Difference

Food allergies affect roughly five to eight percent of all children. A food allergy diagnosis can dramatically alter one’s life as it requires constant vigilance during meals and snacks and preparation in case a severe allergic reaction occurs. While many people experience various symptoms after eating certain foods, it is important to understand the differences between food allergy and intolerance.

What is an allergy?

An allergy is a response by the immune system to a food allergen, which causes symptoms that occur immediately (within a few hours) and with every exposure to that allergen.

While any food can potentially cause an allergy; peanuts, tree nuts, eggs, milk, wheat, soy and fish/ shellfish cause more than 90 percent of allergic reactions

What is an intolerance?

An intolerance is a non-immunologic response to a food that mainly causes gastrointestinal symptoms with exposure.

Common food intolerances include lactose (milk), wheat, gluten, fruits and vegetables.

Allergy Symptoms vs. Intolerance Symptoms

So how do you know if your child has an allergy or an intolerance? The good news is, for the most part, signs and symptoms vary between the two. The lists below illustrate the different reactions you might see in your child if they have a food allergy or intolerance.

AllergyIntolerance
HivesNot always reproducible
SwellingMore subjective complaints
Difficulty breathingNot always immediate
Difficulty swallowingBloating
VomitingGassiness
Hypotentions (passing out)Heartburn
AnaphylaxisVomiting
Constipation
Diarrhea

Talking to Your Child’s Doctor

If you think your child may have a food allergy or intolerance, talk to your child’s pediatrician about the symptoms your child is experiencing. Preparing answers to the following questions will help your pediatrician determine if a referral or testing is necessary:

1. What do you think your child is allergic to?
2. What do the signs and symptoms look and feel like?
3. How long did it take for symptoms to begin after your child ate/encountered it?
4. How long did the symptoms last?
5. Need for treatment and what type of treatment
6. Does this happen every time your child eats/encounters it?
7. When was the most recent reaction?

How will a doctor test if my child has an allergy?

The history is the most important part of the evaluation. Allergy testing may be indicated when the history suggests a possible food allergy. If the history does not suggest a food allergy, then testing may not be necessary.

Testing options include:

  • Skin prick testing
  • Serum specific IgE testing
  • Oral food challenge

Some studies show that up to one in three people report having a food allergy. However, only one in 20 actually do. This discrepancy often comes from an incomplete understanding of the differences between food allergy vs. intolerance, or even normal response to some foods. If you have concerns, talk to your doctor.

For more information about Nationwide Children’s allergy and immunology clinics, click here.

David Stukus, MD
Dr. David Stukus is an Associate Professor of Pediatrics, Section of Allergy and Immunology, at Nationwide Children’s Hospital. Dr. Dave, as his patients call him, is passionate about increasing awareness for allergies and asthma. His personal life is filled with fun and chaos as he is married to a Pediatric Emergency Room physician and they have 2 energetic children. His rare free time is spent following his beloved Pittsburgh and Ohio State sports teams. Follow Dr. Dave on Twitter @AllergyKidsDoc for great allergy/asthma tips!

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