Should providers rethink how they test a child for a food allergy?

skin prick test food allergy
(NIH/Wikimedia Commons)

A food allergy diagnosis can save a life, but comes with its share of hardships. Apart from the costs associated with food avoidance and medical care, children with food allergies (and their families) can face stress, anxiety and a sense of social isolation. John Lee, MD, director of Boston Children’s Hospital’s Food Allergy Program, recently told Scientific American (SciAm) that:

“Food allergies can be terribly isolating for a kid. One parent told me his child was forced to sit all alone on a stage during lunch period. And siblings can feel resentful because in many cases parents don’t feel they can take family vacations or even eat dinner in a restaurant.”

The problem here isn’t food allergies themselves, but the diagnostic tests we use. As SciAm reports, the standard skin prick test can have a 50 to 60 percent false-positive rate, labeling many children as food allergic who actually aren’t.

One answer: Use a better food allergy test. Lee advocates for placebo-controlled testing. While these tests are more resource intensive, he tells SciAm that they are also much more accurate:

A potential irritant is eaten, and the body’s response (a rash, say, or swelling) is compared with what happens after eating something that looks like the irritant but is benign. For example, a patient who might be allergic to eggs is given a tiny amount of egg baked into a cake, along with a taste of egg-free cake. Ideally, the test is double-blind, meaning that neither the patient nor the allergist knows which cake contains egg. The accuracy rate of these tests, for both positive and negative results, is about 95 percent, according to Lee.

Read more about problems with food allergy testing in Scientific American.