Study: Food Allergy Guidelines Needed
Overdiagnosis Common With Skin, Blood Testing
Skin Prick, Blood Test Often Unreliable
Food challenge in a physician’s office or hospital setting is the most reliable way to confirm a specific food allergy, but such testing is costly, time consuming, and can result in anaphylaxis.
Because of this, most food allergies are diagnosed through skin prick or blood testing alone, which often leads to overdiagnosis.
“Children who come to see me often leave with fewer food allergies than they came in with,” pediatric food allergy specialist Todd David Green, MD, of Children’s Hospital of Pittsburgh tells WebMD.
In the absence of other indicators like a strong family history of food allergies, Green says skin prick and blood tests should not be relied on alone to confirm a food allergy.
Lynda Mitchell, who is president of the advocacy and education group Kids with Food Allergies, agrees.
“We tell parents that about half the time a skin prick or blood test may not be accurate and that patient history, physical examination, and other factors need to be considered,” she says.
Mitchell says overdiagnosis of food allergies is common and can be devastating for a family.
She cites the case of a Minnesota 3-year-old who had been fed highly specialized formula through a tube in his stomach since he was a baby because his food allergies were thought to be so severe.
Extensive evaluation at Denver’s National Jewish Hospital, which runs one of the nation’s top pediatric food allergy programs, revealed no allergic reaction to more than a dozen previously suspect foods.
“The child was able to eat Thanksgiving dinner with his family,” she says.