Researchers from the American College of Allergy, Asthma and Immunology (ACAAI) examined records of people with known tree nut allergies and tested them for allergies to other tree nuts. They found that among those who are allergic to one nut, most passed an oral food challenge to other nuts despite having positive tests that are more commonly used.
The scientists believe that the inaccuracy of the skin prick and blood tests are to blame. "Too often, people are told they're allergic to tree nuts based on a blood or skin prick test," said Christopher Couch of ACAAI.
Unreliable testing may be creating more allergy than there really is, the researchers conclude.
Oral food challenges are time-consuming and costly in comparison to skin prick tests and are thus often "last resort" food allergy tests. They require a trained allergist and usually several office visits to conduct.
The researchers also noted that those allergic to peanuts were rarely allergic to tree nuts, though many were sensitive to them.
The research study was published in the Annals of Allergy, Asthma and Immunology.