Study: Food Allergy Guidelines Needed
Overdiagnosis Common With Skin, Blood Testing
WebMD News Archive
Food Allergy Prevalence Unclear continued...
“Having a basic framework for diagnosing food allergies will help us better interpret studies evaluating diagnosis and treatment,” she says.
According to the review, between 1% and 10% of people in the U.S. have food allergies.
While individual studies suggest an increase in allergic food reactions, this could not be confirmed.
Among the other review highlights:
- The safety and effectiveness of immunotherapy for desensitizing patients to food allergies remains unknown. The treatment involves a challenge with minute amounts of the allergen.
Probiotics in conjunction with breastfeeding, hypoallergenic formula, or both might help prevent food allergies in high-risk infants, but the independent impact remains uncertain.
Skin prick testing, blood testing, and food challenges all play a role in diagnosis, but all also have their drawbacks.
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.