Ask the Allergist: What Is a Food Allergy?

Editor’s note: Any medical advice presented here is expressly the views of the writer and Red Tricycle cannot verify any claims made. Please consult with your healthcare provider about what works best for you.

At Ready, Set, Food!, we’re committed to all aspects of food allergy education, so families can make informed decisions about their children’s nutrition and give their babies the best defense against food allergies. 

So What Is A Food Allergy?

A food allergy occurs when the body’s immune system mistakenly responds to certain foods that it thinks are harmful. Our immune systems defend and protect us from foreign invaders like certain viruses and bacteria.

Food allergies occur when the immune system over-defends and treats certain proteins in foods as foreign invaders. These proteins are called allergens and our immune systems make special allergy antibodies called IgE antibodies to these allergens to help fight them off. These antibodies can help our cells cause a reaction each time a person eats a food they are allergic to.

In babies, hives and vomiting are the most common symptoms of a food allergic reaction. These symptoms usually occur within seconds to minutes and almost always within 2 hours. In addition, one reaction can vary widely from the next in the same person. One cannot predict what type of reaction a person will have each time they eat a food that they are allergic to. Food allergies are most common in children, but a food allergy can occur at any age.

IgE-mediated v. Non-IgE-mediated food allergy

• IgE-mediated food allergy is different than non-IgE-mediated (delayed-type) food allergy
  • For instance, some infants have a delayed allergy to milk which can cause blood and mucus in the stool hours to days after the ingestion of milk.
  • Another example is Food protein-induced enterocolitis syndrome (FPIES) which is a non-IgE-mediated disorder that usually occurs in young infants. Symptoms include chronic vomiting, diarrhea, and failure to gain weight or height. When the allergenic food is removed from the infant’s diet, symptoms disappear. Milk and soy protein are the most common causes

Food Allergy Testing

Validated food allergy tests like skin prick tests or blood tests look for the presence of IgE antibody. If the tests are positive, they show that a person produces IgE antibodies to food allergens. But blood and skin tests alone cannot be used to diagnose a food allergy. A person does not have a food allergy unless they also have clinical symptoms. There is also a chance that a person could have a “false positive” on their skin or blood test.

An oral food challenge which exposes a person to their potential allergenic food in small doses, slowly increasing over time with careful observation in a medical facility to watch for signs of an allergic reaction, is the only way to definitively diagnose a food allergy.

However oral food challenges can be risky, thus many times they are avoided and a diagnosis is made based on the other tests above plus the person’s medical history. A patient’s medical history (their reported experiences after exposure to the specific food) is the most important part of the evaluation for a food allergy diagnosis.

A Recent Breakthrough in Food Allergy Prevention

Thankfully, recent landmark studies (LEAP, EAT, PETIT) have proven that exposing babies to food allergens early and often can significantly reduce their risk. In addition, new medical guidelines from the American Academy of Pediatrics, the National Institutes of Health (NIH), and the American Academy of Allergy, Asthma, and Immunology (AAAAI) have been published supporting early and sustained allergen introduction.

Along with a team of leading allergy experts and parents, I helped develop Ready, Set, Food!, a gentle, guided system based on these medical guidelines. After over a year of research and development, we’re proud to offer Ready, Set, Food! to families like yours, making it as easy and safe as possible to introduce babies to peanut, egg, and milk in the amounts used in the landmark clinical studies, which showed the potential to reduce babies’ risk of developing an allergy to these foods by up to 80%.