The rising rate of food allergies

Flawed testing may be at fault

For many people with life-threatening food allergies, the simple act of choosing what to eat can be akin to navigating a landmine. Eight culprits comprise 90 percent of all allergic reactions: egg, peanut, tree nuts, wheat, fish, soybeans, shellfish and cow’s milk. Because so many allergy-causing foods are used as ingredients in other foods, avoiding the triggers can be a challenge.

According to the National Center for Chronic Disease Prevention and Health Promotion, about 4 to 8 percent of children and 2 percent of adults have food allergies, and the number is rising. From 1997 to 2007, reported food allergies increased by 18 percent among children under the age of 18.

But a new federally funded report is questioning this prevalence of allergies. Commissioned by the National Institute of Allergy and Infectious Diseases, the report states that it’s unclear if food allergies are truly increasing, or if they are simply being misdiagnosed.

Diagnosing and Managing Common Food Allergies,” recently published in The Journal of the American Medical Association, looked at 72 different studies and compared three popular methods of diagnosis: the skin-prick test, which involves pricking the skin with an extract of the food in question and looking for swelling or redness; blood tests, which measure the presence of food-specific antibodies in the blood; and the placebo-controlled oral food challenge, in which a patient blindly ingests individual doses of various foods, some of which are suspected of causing an allergy.

The conclusion: None of the tests demonstrate any statistical superiority, and there’s a lack of criteria for proper diagnosis. Even more revealing, patients with symptoms like rash or abdominal discomfort who are diagnosed from blood or skin-prick tests alone have less than a 50 percent chance of actually having an allergy.

“Probably half of the people who report that they have a food allergy don’t,” Dr. Marc Riedl, assistant professor of clinical immunology and allergy at UCLA and one of the report’s authors, said in a telephone interview. Up to 17 percent of people self-report as having food allergies, he said, but in reality, the number is much lower.

The consequences of misdiagnoses

Why this rampant overdiagnosis? One reason is that a person can have a positive skin or blood test to a food allergen without having an allergy to that food. Cross-reactivity – such as sensitivities to ragweed pollen cross-reacting with allergies to melons – may also account for false positives in blood tests. A person who is allergic to shrimp may test positive to lobster and crayfish.

“A positive blood or skin test does not equate to a true food allergy,” Riedl said. In many cases, clinical symptoms such as acute hives, asthma or diarrhea are lacking. “People have altered their diets and lifestyles in dramatic ways, but when you review their clinical history there’s nothing to suggest they’re at risk for severe allergic reaction. Much of the time, their diagnosis is inaccurate.”

The tests are not meant to be taken as gospel. “With any test in medicine, you really need to take a patient’s history first,” Dr. Gary Stadtmauer, an allergist-immunologist in New York City, said in a telephone interview. “The problem is that some doctors use allergy tests as if they have a high predictive value. The test is imperfect. You have to make sure if it makes sense to do the test in the first place.”

Misdiagnoses of food allergies can have lasting effects, ranging from anxiety to unnecessary dietary limitations. Overdiagnoses 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 food challenge method, which the report’s authors refer to as “the criterion standard” for testing, is rarely used because of its time intensiveness and risk of severe allergic reactions.

Another time-consuming method of allergy testing is to keep a food diary, see if there is a pattern of allergic reactions, and then embark on an elimination diet, removing suspected foods one by one to see if symptoms disappear. But like the food challenge, there’s a lack of standardized criteria for what constitutes an allergic reaction. As a follow-up to the report, a panel of allergy experts is drawing up guidelines for diagnosing and defining food allergies, with a draft set to be released by the end of June.

 
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Comments

  • Ellie P.R.

    A little bit of knowledge can be an irritating thing.
    Having a son with multiple food allergies seemed to make everybody I ran into an expert on allergies. Frankly, my son could have told anybody more about his allergies by the time he was 2 than any of the people who gave me advice at parties and in check out lines.
    At times I felt like printing up pamphlets: “Yes, we know for sure he has allergies. They are as plain as the hives that cover his face and have been covering his face since he was 4 months old. No, I am not going to try to give him just the yolk or just the egg white because our Allergist recommends complete avoidance. No, we are not going to give him a bit at a time because that is not what our Allergist recommends and because I hate playing ‘Will his airways close’ roulette with my small child. Yes, pancakes and cake and chocolates and most treats do have something he is allergic to and will likely result in a worse reaction because they have multiple allergens AND if you sit there telling me that it is cake not scrambled eggs and milk after I say no, I might hurt you.”
    By the way, after over 4 years of avoidance he outgrew all of his allergies and will be off to Kindy this fall without a worry.

  • CA

    Great article in general. My only specific complaint is that it seems to downplay the very real and life threatening food allergies that do exist. The possibility for sudden onset, severity and sensitivity related to these allergies is absolutely a matter of life or death and that should, under no circumstances, be forgotten.

  • HG

    There should be an article about the under-diagnosing of food allergies as well. I am severely allergic to mold (includes anything fermented i.e. wine, blue cheese, etc) It took several life threatening reactions to be properly diagnosed.

  • smilinggreenmom

    There is so much and so many people that do not fully understand the scope of this problem that is increasing at an alarming rate. Our son has dealt with his severe allergies, food intolerances and terrible eczema since he was an infant. We took him to many specialists, and not one of them had answers. In fact, the tests were very frustrating too because each one contradicted the last. We do know of severe food reactions that we keep him away from and as for the eczema and intolerances, his Belly Boost chewable probiotic has changed his life so much for the better. He can now eat so many foods that would once make his body flare and his skin is way better now too. I highly recommend!

  • jimmy capra

    A few comments:

    1) As anyone who has dealt with children with food allergies knows, it is abundantly clear that medical science has no idea what they are talking about when dealing with food allergies. The article above shows this, as the “experts” cited do not even know how to describe what an actual allergic reaction is.

    2) The food suppliers are mostly at fault for the large increase in allergic reactions to the wide variety of foods that people now suffer from. We have had great success in eliminating allergic reactions simply by avoiding any processed food that strips out the natural elements of the food “in the name of our ‘safety’ ” and replaces them with industrial waste products, aka. “fortification”.

    3) For those of you who do not know of NAET, it is an amazing treatment for allergies. It is completely dismissed by medical science for being ineffective. (I have to ask those medical professionals: so what do you do all day……other than treat people with ineffective allergy remedies???? ) For anyone looking for help, please look up NAET online and find a practitioner near you. It is amazing and actually deals with the source of the allergy, allowing one to eat the offending food without issue.

    4) Food allergies are real. The effect FAR more people than anyone even realizes. I see it EVERY day as I watch people eat. They have no idea that they are suffering from an allergy, but I can see their bodies react in all the classic ways that children react to allergens (red nose, red cheeks, hives, dark circles under the eyes, pallor, yellow color, etc….) No one seems to want to believe it ( I didn’t until I was forced to truly understand it) but it is rampant in our society. What should be reported is not the over-diagnosis of food allergies, but the VAST under-diagnosis. Also, what should be reported on is the total ineffectiveness of medical science to even understand allergies, let alone to effectively treat them.

    Words from a parent of 2 allergic children with now 5 years of intense learning, experimentation, and treatment under my belt.

  • mc

    It is not only the rising rate of food allergies but what we consume is also causing major problems. Overeating, for example, is a major concern in USA. Childhood obesity is the main reason for diabetes, heart problems, and other illnesses such as cancer.
    Recent Health News about onset of puberty among girls is really scary. Girls between the ages 7 and 8, reach puberty very soon. This will lead to serious health problems such as breast cancer, ovarian tumors, mental illnesses. etc..

    Many American parents are really worried that their daughters may not be mentally prepared to handle puberty at such an early age. Endocrinologists and Gynecologists mention that beef eating and consuming dairy products can also cause premature puberty and weight gain.

  • http://blogs.babble.com/strollerderby/2010/08/26/take-me-out-to-the-ball-game-but-hold-the-peanuts/ Take Me Out to the Ball Game… But Hold the Peanuts? | Strollerderby

    [...] of Medicine, says, “Many food allergies are actually food intolerances.”  He told PBS, “People commonly think an adverse reaction to something is a food allergy. That’s a leap [...]

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    [...] of Medicine, says, “Many food allergies are actually food intolerances.”  He told PBS, “People commonly think an adverse reaction to something is a food allergy. That’s a leap [...]

  • http://www.facebook.com/people/Lisa-Roy/100001962201237 Lisa Roy

    The percentage of food allergies is majorly increased people should take care of the things they eat and if they are suffering from any allergies they should visit the good physician but should not ignore it even small rashes can lead to death . http://www.aboutallergy.net/food-allergy-reactions.html

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  • bookworm worm

    Doctor’s mistakes can be made which leads to the unnecessary harm or suffering of a patient.wrong diagnosis

  • bookworm worm

    Doctor’s mistakes can be made which leads to the unnecessary harm or suffering of a patient.wrong diagnosis

  • Tfrazier6220

    Ohh, it’s over diagnosed? I should start to keep a food diary of all the times my son has come in contact with a peanut and needed epi and a rush to the E.R?
     
    Nobody reports they have a food allergy for fun, and I don’t think anybody just randomly chooses to get to an allergist and be tested.
     
    It’s articles like these that make it hard to make schools safer and raise awareness.
     
    Take little seven year old Ammaria who died in a Virginia public school last month. All the headlines say things like “Child dies from peanut allergy”, but if you read the news coverage her death was catogorized as death from cardiac arrest. Some researcher will come along and try to find data on how many deaths there are among children from food allergies and Ammaria will not even be included. Like so many others she’s even robbed of her voice to name her killer in death. Cardiac Arrest, Pulmonary arrest, choking, etc., all common misdiagnosis(s).

  • Colleen Phillips

    Overdiagnosed? My grandson is the first person in the entire histories of every side of our families to have a food allergy, and yes, it is a true allergy, as any exposure brings on severe hives and other life threatening reactions. During my entire childhood, and I lived in a dozen states and attended as many schools, peanut allergies were unheard of, and peanut butter was served freely and consumed enthusiastically in every school cafeteria I ever frequented, and there was no problem whatsoever. Instead of a cop out from the medical community, we desperately need research to determine the cause of the increase in, not only allergies, but leukemia, brain cancer, and autism in children. Oh forgot to mention, my granddaughter is the first person ever in the histories of our families to have autism. Something is going on, and it’s got to be environmental, because the rise has been so rapid.

  • Colleen Phillips

    I don’t think processed food is the problem, at least as far as the increase in allergies are concerned. Highly processed, nutritionally denuded, refined foods have been freely consumed by the majority of Americans for over 50 years. During the 50s and 60s, kids grew up on inferior baby formula rather than breast milk, sugar coated cereals, and white bread sandwiches made with mystery meat bologna and processed American cheese product. We snacked on Vienna Sausages and Spam and white flour Saltine Crackers. When we did eat fruits and vegetables, they were coated with DDT. There was always room for Jello! And peanut allergies were virtually unheard of. As I mentioned above, my grandson, born in 2009, is the first person ever in our families to have a food allergy. I think there is an environmental cause, but highly processed food predates the food allergy epidemic by too many years for that to be the main cause.