Food Allergy Misdiagnosis: Know the Facts
Food allergy is a serious medical condition affecting up to 15 million people in the United States, including 1 in 13 children; and it’s rising. While the increase appears to be real, so does the increase in misdiagnosis.
Families are needlessly avoiding certain foods and spending hundreds of dollars on costly non-allergenic supplements. Misdiagnosed allergies can even put children at risk for malnutrition.
There’s also the chance that avoiding food in the mistaken fear of allergy may be making the overall problem worse, making children more sensitive to certain foods when they finally do eat them.
The culprit appears to be the widespread use of simple blood tests for antibodies that could signal a reaction to food. The tests have emerged as an easy alternative to skin testing for practitioners who are not trained allergists, and “food challenge” tests, which measure a child’s reaction to eating certain foods under a doctor’s supervision.
While the blood tests can help doctors confirm food allergy, because there is a very high false positive rate, screening blood testing without a history of reaction to a specific food is often misleading. There is an important difference between having allergic antibody to a food (detected by skin test or blood test) and actually being allergic to that food. False positive results may occur because tests may fail to distinguish between similar proteins in different foods. It is common when food allergy testing is used as a screening test for many foods to test positive even though they are eaten routinely without problems.
The most important question in diagnosing food allergy is whether the child has tolerated the food in the past. While some severe allergies are obvious, parents given a positive blood test result should seek advice from an experienced allergist who performs medically supervised food challenge testing, the gold standard for diagnosing food allergy.
Even when a food allergy has been confirmed, parents should continue to work with their allergist, because some allergies are outgrown particularly allergy to milk, eggs, soy and wheat. There are strategies, that work for some children, to increase the likelihood that allergy to milk and eggs will be outgrown.
Misdiagnoses of food allergies can have lasting effects, ranging from anxiety to unnecessary dietary limitations. Over-diagnoses can also trivialize the severity of life-threatening, immune-mediated food allergies which account for about 150 deaths in the U.S. each year. Still, blood and skin tests remain the most frequently used methods of diagnosis. The best approach is to limit food allergy testing to those foods likely to cause an allergic reaction based on the history of problems. Many problems attributed to food allergy by the public and even some physicians don’t have the features of a true allergic reaction at all.
Many symptoms thought of as food allergies are actually food intolerances. Food intolerances are more common than food allergies, and are not caused by the immune system. But symptoms of intolerances, like abdominal cramps, may be similar to those of allergies. Intolerances include many food related problems like insomnia from caffeine, runny nose from pepper or gas from beans but can be caused by factors such as food poisoning, additives like MSG, and high sulfite levels in some wines, and lactose in milk.
To know for certain that you have a food allergy it’s important to be tested and diagnosed by a Board Certified allergist/immunologist. Patients who have been through our innovative food allergy immunotherapy program have inspiring stories to share.