Food Reactions
Over the past 10-15 years, the number of children with common food allergies has been going down due to research and pediatricians promoting early introduction of foods in kiddos including those common allergy-causing foods such as tree nuts, eggs, dairy, soy, shellfish, wheat, and berries. But some kids still do have food allergies.
True food allergies usually manifest with full-body symptoms representing varying degrees of anaphylaxis. If a kiddo eats something and within 2 hours they develop hives all over their body; swelling of the lips, eyes, or tongue; trouble breathing or wheezing; violent vomiting; or any combination of these, this likely indicates a true food allergy that is mediated by IgE antibodies that are not cool with the offending food being in the body. These allergies are usually evaluated with skin testing, blood testing (though not very accurate), or possible oral food challenges in the pediatric allergist's office with a watchful allergist taking note of any reactions. Children with a food allergy of this type should always have an EpiPen close by, including at school and sports activities to help stop an anaphylactic reaction from occurring if they are exposed to the food that they are allergic to.
Some children are just sensitive to foods, meaning their bodies don’t particularly enjoy them but they do not develop anaphylaxis. Examples of this are when kids eat certain foods and those foods get on their skin, they can have a contact dermatitis or contact allergy on that part of the skin but will not develop a rash or hives elsewhere. Or there are times when a kiddo eats a certain food and every time they do so, they feel nauseated or have diarrhea. We usually figure these sensitivities out with a good food history and food elimination diet to see if we remove the concerning food if those symptoms do not recur.
Food intolerances have to do with the body’s inability to process foods due to a lack of enzymes in the gut. The most famous example of this is lactose intolerance when some people’s digestive systems lose the enzyme responsible for processing the milk/dairy sugar lactose as they age due to a lack of the enzyme lactase. If a patient eats lactose and they lack the enzyme, they get bloating, nausea, diarrhea, etc. But often these symptoms will be cured if a patient is given the missing enzyme in a pill form such as Lactaid.
There is another type of food allergy called an oral food allergy where the mild allergy occurs in the mouth, ears, and throat; If a person eats certain fruits or vegetables raw or minimally processed, they can get tickly mouth, throat, and ears. When you cook or process these fruits or vegetables, the protein that is causing this reaction is denatured (making it not look like the original protein), and the person will not have those symptoms. The really interesting part of this type of food allergy is that it often correlates to environmental allergies like flower, grass, and tree pollens with a high level of accuracy as described in this link from Cleveland Clinic:
https://my.clevelandclinic.org/health/diseases/23996-oral-allergy-syndrome