Controversy in Diagnosing Food Allergies

Patient Expert

A recent review commissioned by the National Institute of Allergy and Infectious Diseases (NIAID) entitled Diagnosing and Managing Common Food Allergies   published this May in the Journal of the American Medical Association (JAMA) finds that there is much ambiguity in the food allergy world. In response to this review, we've seen a flurry of articles in the media regarding the prevalence of food allergies, and the potential for misdiagnosis.

The report found that there is no universally accepted definition for food allergy, no well-accepted criteria for diagnosing food allergies, and that some people who believe they have a food allergy actually do not.   Nothing here is a surprise to those of us in the food allergy community. We are frustrated as well that there is no quick and simple test that -on its own- can tell you if you are allergic to a particular food.   We're well aware that to the general public "allergy" can mean many different things.     Personally, I cringe when I hear someone say something like "I'm allergic to milk, but I eat a little ice cream sometimes."   This misunderstanding of what a true allergy is, allows people to treat food allergies too casually. They wonder why they can't just pick the walnuts off the top of my son's brownie. Ugh..

Most allergists will acknowledge that the increase in awareness likely does send more us to their offices for testing, yet these physicians take extraordinary care to interpret these results in conjunction with personal histories or food challenges.

There are issues with diagnosing food allergies as well. We know that a positive test for IgE antibodies to a food does not necessarily mean that the person is allergic to that food.     It's true that skin prick or blood test results can be falsely positive, but the opposite can also occur.   There are variations in the sensitivity of both types of testing.   Studies have shown that patients can still react (confirmed with medically supervised food challenges) when results are negative.   Food allergy testing is not black and white.   While skin prick and blood tests have their limitations, the double-blind placebo-controlled food challenge (DBPCFC) is considered the gold standard for diagnosis. These tests are time-consuming, costly (often not covered or partially covered by insurance) and are not without risk of anaphylaxis. (In one recent study, 43 percent of patients experienced an allergic reaction during a food challenge).   It's difficult these days to schedule a food challenge as allergy clinics across the country are booked a year or more in advance

The silver lining to all of this media attention is that it highlights the urgent need for more research into this life-changing disease.     Meticulous avoidance of any food is extremely difficult, and the added expense of "food allergy friendly" food items makes more research increasingly important to cash-strapped families struggling with mounting medical expenses in a recession-based financial world.   The anxiety that often accompanies a diagnosis of food allergies adds an emotional toll.     With continued research, we look forward to the day when we have access to safe, inexpensive, and definitive methods of diagnosing food allergies and reliable statistics on prevalence.   The study authors make an excellent point when they explain that "Furthermore, the overdiagnosis or misdiagnosis or food allergy by medical practitioners obscures the substantial morbidity caused in patients truly affected by immune-mediated food allergy and serves to perpetuate some public misconceptions that food allergy is a trivial medical condition."

Food allergies, whether formally diagnosed or not, can and do cause serious and even fatal reactions.   Although we may need more high-quality studies to show it, many indicators point to an increase in all allergic disease, including food allergies.     No one is disputing that individuals are misdiagnosed. Unfortunately the opposite is also true and when the diagnosis is missed, the stakes are much higher.   We can talk about numbers all day long but what sticks in my mind are the parents who have lost children to fatal anaphylaxis and later said "We wish we would have known." or "We wish he'd have been diagnosed before it was too late."   This is today's reality, no doubt.