The diagnosis of a food allergy involves many factors, primarily a reaction history that is consistent with an IgE-mediated reaction. Diagnostic testing involving both serum IgE assays and skin testing with food allergen extracts help to confirm a food allergy diagnosis.

These diagnostic tests on their own are not sufficient to confirm a food allergy. Because these diagnostics test are highly sensitive but not specific, they can present with many false positive or clinically irrelevant results. This can lead to confusion and unnecessary food avoidance, especially in young children.

Because of the low specificity of food allergy tests, food panel testing should not be conducted. Food allergy testing should be targeted, based on the foods eaten prior to a reaction. Individual food allergens can be searched on the LabCorp website.

Food intolerance symptoms are not IgE-mediated. They are delayed symptoms that are due to digestive abnormalities. Food IgE panel testing does not provide any information for food intolerances. There are no reputable food intolerance tests at this time. Evaluation for other primary gastrointestinal disease, food diaries to determine triggering foods and/or implementation of a FODMAP diet can help with food intolerance symptoms.

It is important to note that prolonged and complete avoidance of a food may increase the risk of developing an IgE-mediated reaction to that specific food. FODMAP diets should be used as a guide to determine what foods to limit in the diet. Here is a helpful resource for patients about FODMAP diets. Serum IgE food assays and skin testing to food extracts are also not helpful to identify food triggers for migraine headaches and acne. Foods that may worsen these symptoms are not mediated through mast cells and IgE antibodies. Food diaries can also be helpful to identify foods that reproducibly worsen these conditions.

If there are any questions or concerns about these topics, please contact Melanie Chong, MD, at melanie_chong@valleymed.org

The above guidelines are resourced from Choosing Wisely: American Academy of Allergy, Asthma & Immunology recommendations