Do Siblings Usually Share Food Allergies?

If one child is allergic to a specific food, then their brother or sister is probably going to have the intolerance as well, right? Not necessarily.

“Too often, it’s assumed that if one child in a family has a food allergy, the other kids need to be tested for food allergies,” said lead author Ruchi Gupta, MD, MPH, who will go further in depth at the 2015 American College of Allergy, Asthma, and Immunology Annual Scientific Meeting (ACAAI 2015) in San Antonio, Texas.

Gupta and colleagues evaluated 1,120 children who had a sibling with a food allergy. They reviewed the children’s medical histories, performed a blood test (IgE), and skin prick testing. Allergic reactions were also recorded, including hives, wheezing, vomiting or stomach cramps, shortness of breath, dizziness or feeling faint, or tightness in the throat.

“But testing for food allergies if a reaction hasn’t taken place can provide false-positives, as we saw in our research. More than half the kids in the study had a sensitivity to a food, but they weren’t truly allergic. Kids who have a food sensitivity shouldn’t be labeled as having a food allergy,” Gupta explained.

It was determined that only 13% of the participants themselves had a food allergy despite the fact that their sibling did.

Food allergy tests are not sufficient tools to predict future risks if the person has never eaten the food and exhibited a reaction. There has never been hard evidence showing the correlation of food allergies in siblings, and this study certainly didn’t indicate that either.