Atopic dermatitis (AD) can increase the risk of developing food allergies. Many patients with moderate to severe AD have food allergies, while others do not, so the relationship is not necessarily linear. Targeted testing may assist in identifying appropriate management strategies, potentially preventing unnecessary food avoidance.

AD is a risk factor for the development of food allergies in some, but not all, patients. The dual-allergen exposure hypothesis proposes that food allergen sensitization can occur through the broken skin barrier found in patients with AD, for example, from food proteins in household dust. In contrast, early oral exposure can hopefully increase tolerance. Food allergy testing often results in false-positive results in patients with AD because many of these individuals have elevated levels of IgE antibodies, so the interaction is complex. AD prevention studies, such as the SEAL and the PreventADALL studies, have not yet shown us a way to prevent AD and potentially decrease the risk of sensitization to food over time.

Diagnosing food allergies in the setting of AD should include a history of ingesting the food and having an allergic reaction, not just an AD flare. In our study published in Pediatrics, we did oral food challenges (OFCs) in patients with positive skin and serum IgE blood tests to multiple foods, and 84% to 93% of those foods could be reintroduced into the diet after an OFC, showing the high rate of false-positive testing. Therefore, the patient’s clinical history should really be what guides our testing. Sometimes parents will not introduce a food without a negative test. In those cases, I will do the skin or blood test with the caveat that I will recommend an OFC if the result is positive without a previous exposure to the food. Unfortunately, many centers and private practices do not do OFCs, leading to a long wait time for these tests. This can delay the introduction of the foods, which potentially results in a missed opportunity to prevent food allergies through early introduction.

Pediatricians and dermatologists in the private practice setting are encouraged to refer all children with suspected food allergies to allergists, who have the time, expertise, and access to effective treatments for management. Allergists prefer targeted testing rather than IgE panel testing, which, in patients with AD, may show more false-positive results and lead to unnecessary food avoidance.