Common food allergy myths

As a pediatric allergist, I receive a lot of questions from parents and physicians regarding food allergies. Whether it’s from the Internet, or even well-intentioned medical providers, misinformation is abundant. Here are some of the common myths I hear on a regular basis.

Myth #1: Can my child have an unknown food allergy?

This is very unlikely. Food allergies occur when the body produces an allergy antibody called immunoglobulin E (IgE) against specific foods. When a food allergy is present, symptoms occur within a few minutes, or up to 2-3 hours later, and happen every time a food is ingested. Symptoms can be mild or severe and include any combination of red, itchy bumps (hives), swelling, difficulty breathing, difficulty swallowing, vomiting, or passing out.

The best test to determine if allergy is present is what happens after a child eats a food. If they eat a food without any problems, they are not allergic. “Hidden” food allergies do not occur.

Myth #2: This test says my child has a severe food allergy.

Skin prick and blood tests can evaluate for the presence of IgE to specific foods. These tests are not good screening tests due to high rates of false positive results. The detection of IgE alone does not diagnose food allergy. IgE tests should only be applied when a child has a history suggestive of a food allergy reaction. Overuse of these tests leads to over-diagnosis of food allergy and unnecessary dietary elimination. Lastly, the size of the test result indicates the likelihood an allergy is present, but does not indicate how severe the reaction may be.

Myth #3: No dairy until 1, no eggs until 2, and no nuts or seafood until 3 years old!

We used to think avoidance of allergenic foods would prevent allergies but now we know that early introduction can promote tolerance. Since 2008, the American Academy of Pediatrics has recommended introduction of all foods beginning around 4-6 months of age, or when the infant is developmentally ready. In 2017, new guidelines were released that recommend early introduction of peanut before 12 months of age specifically to prevent peanut allergy. If an infant has severe eczema or egg allergy, they should undergo peanut allergy testing first, otherwise infants can incorporate into their diet without testing.

Myth #4: Strawberries are a common cause of allergy.

Not at all. Milk, egg, wheat, soy, peanut, tree nuts, fish, and shellfish account for more than 90 percent of all food allergy reactions. Many children experience localized skin irritation or rash from contact with strawberries, tomatoes, salad dressings, or other fruits. True allergies to these foods are rare and these contact rashes often improve with age.

Myth #5: I’m allergic to iodine, should my child avoid?

First of all, iodine allergy doesn’t exist. It is too small to bind to the allergy antibody IgE and is also present in all of our bodies. Many people with shellfish allergy are mistakenly told they are also allergic to iodine, but this is not true. Shellfish allergy is due to reactions to the muscle proteins called tropomyosin. Second, allergic parents often have allergic children, but specific allergies are not inherited. This goes for medications and venom as well!

These are just a few of the many food allergy myths I encounter on a regular basis. Undoubtedly this information may contradict things you have been previously told. If there’s one thing I’ve learned as a devoted Myth Buster, it’s that misconceptions are abundant.