Peanut allergies are fantastically rare, even among people who ostensibly have peanut allergies.

It’s been known for some years now that very few people who believe that they have peanut allergies actually have peanut allergies, but the precise number hasn’t been known. The University of Manchester tested this by giving peanuts to a bunch of kids with peanut allergies (a bold move, to be sure) and found that 80% of them had no reaction at all. The problem is that the standard test for peanut allergies has a high false positive rate. Parents know that their kid is allergic to something, get him tested for everything under the sun, and “peanuts” often shows up on the list. For whatever reason, parents of kids with peanut allergies think that death is the most likely outcome of peanut exposure so next these researchers intend to study the real severity of peanut allergies. 

Published by Waldo Jaquith

Waldo Jaquith (JAKE-with) is an open government technologist who lives near Char­lottes­­ville, VA, USA. more »

10 replies on “Peanut allergies are fantastically rare, even among people who ostensibly have peanut allergies.”

  1. to be fair, it’s my understand that the very tiny percentage of people who DO have peanut allergies ARE *incredibly* allergic to them — like, possibility-of-death allergic. still, it sucks for the rest of us who love peanuts that there’s such a stigma about them now. they were once one of the few small pleasures that could reliably be found on long plane flights, bad hotel bars, etc.

  2. Sadly, the faux allergy people have made things incredibly difficult for the small minority with genuine allergies. It’s also important to differentiate between allergies and sensitivities.

    As a chef, I’ve experienced this countless times. Diner claims anaphylactic allergy in order to get a special meal, then is seen eating forkfuls of the offending ingredient off of another diner’s plate. When called on it, they often claim that this is a different circumstance and they can eat it in that particular form (sautéed onions vs caramelized, for instance). Or someone who claimed a peanut allergy when it came time to order the entrée, claims that they can eat peanut butter pie “because it’s just so yummy, and I can’t resist.” When questioned regarding the ephemeral quality of their malady, most of these folks will admit that they’ve never actually been diagnosed with said allergy, but they once got a stomachache or “felt funny” (my personal favorite) after eating a particular ingredient. Or they simply don’t like something, and claim an allergy to get people to jump through hoops, rather than just order something else.

    I take allergies very seriously, and find it unfortunate that the large numbers of attention-seeking fakers have now put the veracity of the genuine sufferers in doubt. The modern method of overly neurotic parenting certainly doesn’t help matters either.

  3. I have to say — my mom is one of those “felt funny” people. There is a long list of things she supposedly cannot eat because she is “allergic” to them. I try not to roll my eyes…

    I would think it would relieve a lot of parental anxiety if more reliable or sensitive tests were available to determine if someone has the truly dangerous allergy (to peanuts or to whatever).

  4. This its some statistics guys.

    Lets say the test is 99% accurate, but the incidence rate of anaphylaxis peanut allergy is one in 1000.

    That means the test, while very accurate, is wrong, either false positive or negative, ten times as often as the occurrence of the condition. So for every correct diagnosis there will be ten either false or negative.

    And maybe there are factors beyond the math that trends to make the errors skew towards false positive over negative?

    I used to work tech support for a med school. There was one prof who always said its not a good idea to test large numbers of people for anything, “just in case”. Unless the occurrence its greater than the write rate of the test, you get huge numbers of false positives.

  5. I’m wondering how they ever got people to consent to participate in that study. My friend’s son truly has an anaphylactic reaction to peanuts, but I have a friend who says she’s allergic to garlic and onions, but then says she *can* eat them if they’re finely chopped, which doesn’t make sense.

  6. Is your friend perhaps talking about cooked onions or garlic? There are a number of different proteins that cause allergic reactions that denature or otherwise break down with heat.

    The finely chopped, well, speaking as a former line cook, things chopped finely are gonna have more surface area per unit of volume exposed to the heat source.

    Me, I had an allergic reaction once. In the span of a few hours my entire upper body was covered with hives. Went to a walk in clinic, sent home with antihistamines. Never did find out what caused it, but my dr said almost certainly it was something I ate. He said they could send me for a test, they’d test me for a dozen common allergens, and I’d probably show a response for some of them. Not really useful for figuring out what caused my reaction though.

  7. Augh. Reading about studies like this makes me fear the numbers of allergy-deniers out there who will now decide to run their own experiments on friends and loved ones just to prove that their peanut allergy isn’t real.

    I do have a peanut allergy, and I get frustrated at times with the peanut-allergy-deniers as well as the peanut-allergy-exaggerators: both groups risk my health and possibly my life.

    Peanut allergy deniers in my life include aunts who insist, “Oh, a little bit won’t hurt you”, or “Surely you’ve grown out of it by now” to an ex-boyfriend who was so skeptical of my allergy that he said, “One of these days I’ll put a peanut in something we eat just to prove that your peanut allergy is all in your head.” He became an ex pretty much in that moment.

    Of course, the peanut allergy exaggerators are almost as bad, such as a parent I know who claims her son is allergic to peanuts and demands peanut-free classrooms at school, but who often has an open package of Reese’s Peanut Butter Cups on the dashboard of the car in which she transports her child. OH, really, your son’s peanut allergy is severe enough to inconvenience a whole cafeteria of 300 kids but not severe enough for you to choose a different snack? Hm. Then more and more people concluded that everyone who claims a peanut allergy is just exaggerating, and thus sneak peanut butter sandwiches or peanut granola bars into their kids’ lunches in that supposedly peanut-free room.

    My most recent experience with anaphylaxis was 12 years ago, when I ate a bakery-bought corn muffin which must have had a peanut in it, though I never crunched anything. I was assured that no morning baking included peanuts in this bakery and that everything is thoroughly sanitized at night, but it was my own fault for buying anything from a bakery at all. I went through two self-administered doses of epinephrine before I was able to get to an ER, and by that time my tongue and throat were so swollen that my breathing was as labored as a severe asthma attack, my eyes were reddened slits, and the pain in my chest felt like someone very large was resting on my sternum. Thankfully, with IV epi and a few days of prednisone, I was fine. But I’ve been warned that my next exposure to an ingested peanut might be worse, and that I will need higher doses of epi more quickly to stop the reaction.

    My fiance was a peanut allergy skeptic when we first met, and he LOVES peanut products. Loves, loves, loves them. When we first were dating, he’d fill up on peanut butter and peanut-based treats whenever I was out of town, but he was skeptical when I insisted that not only would I need him to brush and floss after eating peanut products before I’d kiss him, but that in general I’d prefer a full 24 hours of waiting (essentially 2 days’ worth of brushing, rinsing, and flossing) before I’d kiss him with tongue.

    Then one afternoon when picking me up for a date, he kissed me lightly on the lips and I instantly said, “Did you just eat a peanut?!” He insisted he didn’t while my bottom lip began swelling and my heart started pounding, as it does with exposure. He insisted that all he ate all afternoon was a bag of potato chips. As my lips continued to swell, he read the bag in which his chips were packaged and found that it was packaged in a facility that also packages peanut snacks. Since then, he’s become nearly as vigilant as me at making sure peanuts don’t get into our house, but I think he’d still be a skeptic if he didn’t see that reaction (to what could only have been a tiny trace of peanuts) with his own eyes.

    I grew up in the 70’s when no one took peanut allergies very seriously. In fact, I didn’t even have an epi pen ’till I was in college. My brothers had peanut butter sandwiches every day, so I must have been exposed to it at least on surfaces as a kid. I certainly never had a peanut free classroom, but I consider myself lucky to have avoided a life-threatening ingestion back when most people didn’t take it seriously. Sadly, it’s only in the immediate months after a well publicized peanut allergy death (such as the sad story of the little girl in Chesterfield, VA in January) that most people take it seriously when I mention a peanut allergy.

    Something like twice as many people die from peanut allergies every year as die from lightning strikes, so it’s still a tiny number. But no one is publicizing anaphylaxis that doesn’t result in death, and it’s no minor thing. My worst fear is not dying from a peanut reaction; it’s having my EpiPen not work for long enough to get me to an ER before brain damage sets in, and then being revived enough to be alive but have lost all higher order brain function. That happens, but it doesn’t make the news.

    The biggest danger I face from peanuts is my own complacency, but the idea of the allergy deniers out there pulling their own versions of the University of Manchester study really freaks me out.

  8. While reading the literature on food allegies you often see a claim that 150 to 200 people die each year from anaphylaxis (all food allegies not just peanuts) but that seems grossly exaggerated. In 2004, the Centers for Disease Control cited just 14 deaths due to anaphylaxis. The only known registry of deaths from anaphylaxis noted 33 deaths between 1994 and 1999. More people die each year from bee stings. “But we don’t remove flowers from schools or playgrounds,” Dr. Nicholas Christakis, a professor of medical sociology at Harvard Medical School, commented in the British Medical Journal.

    In a new strategy called oral immunotherapy, doctors try to retrain the immune system by hitting it with the offending protein enough times, in increasing doses, that the body’s defenses eventually relent and accept the protein as friend rather than foe. “It’s the first generation of treatment that would make people less or even no longer allergic,” says Dr. Wesley Burks, chief of pediatric allergy and immunology at Duke University Medical Center. On average, children treated this way for a year are able to tolerate the protein equivalent of 15 peanuts, while the untreated group developed allergic reactions after 1 ½ peanuts.

    According to a 2009 Time article the following stats:
    expect deaths in a year

    Food allergies 18
    Lightning strikes 48
    Stings (hornets, wasps or bees) 82
    Malnutrition 3,003
    Accidental drowning 3,976
    Accidental poisoning 23,618
    Flu and pneumonia 63,001

    While an allegy that can kill you is nothing to treat lightly it is worth noting that recent studies do suggest that we have vastly over reacted as a society to the peanut crisis.I know concerned parents only have the childern best interest in mind but I can’t forget parents who were CERTAIN that mercury in vaccines cause their childern to have autism. Some still do even after the orignal research was discredited and no other legitmate study backs the mercury/autism link

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