Diagnosing food allergies is a complicated matter. On top of pinpointing the source of an allergy, there's the added murkiness of the fact that people can outgrow them. So how do you figure out if you're still allergic to something without jeopardizing your health? A new study published in the Annals of Allergy, Asthma & Immunology spotlights something called food challenge, which serves as a pretty good test, reports NPR's The Salt.
According to the Centers for Disease Control and Prevention, food allergies are a "growing" public health concern. In the United States, roughly four percent of Americans live with food allergies. For children, outgrowing allergies is not uncommon: Twenty percent of kids with peanut allergies will outgrow it and anywhere from 70 to 80 percent of children outgrow egg allergies.
How does the oral test work to see if you no longer have the allergy? The patient is exposed to small amounts of the food they're allergic to under medical supervision. Then, if they don't have a physical reaction, they consume some more. In the study, researchers analyzed over 6,000 food challenges. The scientists conducted the study on adults and children they believed had grown out of their allergies. Roughly 86 percent of patients were found to not have an allergic reaction.
"We found that 14 percent of the patients challenged had mild or moderate allergic reactions," study author Carla Davis, an allergist and director of the Food Allergy Program at Texas Children's Hospital, told NPR. "If the symptoms were treated with just Benadryl or another antihistamine, they were considered mild or moderate. She says 2 percent of the reactions were more serious, requiring treatment with epinephrine.
Currently, the two main ways doctors diagnose food allergies is a blood test and a skin prick test. With the former, a blood test measures levels of an antibody called immunoglobulin E. The correlation is generally that a higher level of the antibody translates to a person being more likely to have an allergic reaction. But these tests have their limitations. Bruce Lanser, a pediatric allergist unaffiliated with the study, tells NPR that "both tests only measure sensitization" and "all they can tell us is how likely you are to react when you eat the food."
Overall, the study's findings are promising for those with food allergies. It means you may be able to safely find out if you've outgrown your allergy or not.