When a Food Allergy Diagnosis is Wrong

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Imagine being told your baby had a formula allergy (nope), a goat’s milk allergy (nope), a coconut allergy (nope), and a cow’s milk allergy (nope), and then finding out that in fact they didn’t have any food allergies at all?

That’s exactly what happened to a 15-month-old girl who suffered from a rash and vomiting. It was only through sophisticated testing that she was found to have no food allergies. Zero. Her issues had been caused by run-of-the-mill ailments, and she left the hospital without a single food restriction.

When a Food Allergy Diagnosis is Wrong

So why did this toddler receive an incorrect food allergy diagnosis over and over? The trouble was the skin-prick allergy tests, which haven’t changed much in 20 years. According to Scientific American, skin-prick tests produce signs of irritation 50-60 percent of the time, even when the person is not actually allergic. False positives happen ALL of the time. Whaaaaaat?

Of course, food allergies are extremely serious and can be life-threatening. But it’s also problematic to tell someone they have an allergy when they do not.

Kids who believe they have a food allergy report higher levels of stress and anxiety (so do their parents). Sometimes they have to eat away from their friends. It’s worrisome to fly on an airplane. navigate a class party, take in a baseball game, head to summer camp, or even attend a playdate or a birthday party. It’s expensive to keep two epinephrine injectors with your child at home, at school, at a babysitter’s, etc., not to mention the time parents need to take off from work. It can be hard on siblings without allergies who feel their brother or sister is getting more attention or preventing the family from going out for ice cream sundaes.

So which tests are more accurate than the skin-prick?

Experts say the ideal test for food allergies is a placebo-controlled taste test, where the person is given a potential allergen (eggs baked into a slice of cake) as well as something innocent that looks the same (an egg-free slice of cake), and their body’s response to each food is compared. Pediatric allergist John Lee, director of the Food Allergy Program at Boston Children’s Hospital, says this test is 95 percent accurate but it’s also risky, time-consuming and expensive.

A promising option is the basophil-activation test (BAT) that involves mixing a drop of a person’s blood with the potential allergen and measuring the reaction in basophils (a type of white blood cell). It also earned a 95 percent success rate in the pilot studies, and it’s still in the research phases.

Allergen-component testing has been approved for peanut allergies and challenges peanuts with specific nut proteins rather than a mixture of all nut proteins. It’s helping doctors determine if a person is really allergic to peanuts or just reacting to a single protein within them. An anti-IgE drug that prevents an allergic reaction is being tested now.

Heather Laura Clarke, a contributing writer at Scratch or Sniff, lives in Nova Scotia, Canada, with her high-school sweetheart husband, seven-year-old son, and five-year-old daughter. She writes for newspapers and magazines across Canada and the U.S., and blogs about her family life at Heather's Handmade Life. Follow her adventures on Twitter or Instagram.

6 Comments to When a Food Allergy Diagnosis is Wrong

  1. Juliana Curmi

    Both of my kids (one with a peanut allergy and one with an egg allergy) received their diagnosis via prick test. Before the diagnosis, my son with the egg allergy would eat eggs with no apparent reaction. In fact, he continues to eat baked goods that contain eggs. We were told that he is allergic to the egg white protein and should not eat eggs in the pure form. My son with the peanut allergy never liked the smell or taste of peanut butter, so that allergy diagnosis wasn’t so far off. He was also accidentally given something that had hidden peanuts in it and did have a reaction. We now have Epi pens. I know the tests need to be given every two years, but honestly skin prick tests are so stressful on my kids and me that I can’t bring myself to make the appointments. It would be great if they could test a different way that was more accurate. I really don’t believe that my son has an egg allergy, but because I can’t get him to even step foot in the allergist’s office, we continue to live as though he is allergic.

    • Thanks for sharing, Juliana! It really does make you wonder how accurate the skin-prick test is, doesn’t it?

  2. Destiny C

    My daughter had very severe eczema as an infant. We were referred to an allergy/immunology specialist and they gave her the skin prick test at 6 months old. She tested positive for practically everything they tested for; eggs, dairy, peanuts, tree nuts, even pork and garlic. Since I was still nursing at the time, we went on a vegan plus chicken diet for over a year with no change in her skin! Little by little we reintroduced these foods back into our diet with the exception of nuts and she was fine. She just turned 4 and her eczema has totally cleared up. I am definitely having her retested! It really does cause stress in our home. While we make due with WOWbutter, we are a nut free household and her older brother loves peanut butter. It would be a shame if all of this was for nothing. Thanks for the article!

    • Wow, good for you for going on such a limited diet while nursing, Destiny! Very glad your daughter’s eczema has cleared up and that you were able to reintroduce many of the foods. Hopefully she has outgrown her nut allergy!

  3. Rebecca Ouellette

    I have a son with a severe peanut allergy…known only according to the skin and blood tests (RAST and one other, but not the ones mentioned above). Since we suspected a problem as an infant (at the time it also included dairy), he has never had any nuts and has never had a reaction. It is hard as a parent in my position not to subscribe to “magical thinking” whereby the tests are all wrong and my son actually does NOT have an allergy. When your child has never had a reaction and the only thing telling you he has a life threatening allergy is a test, then it is hard not to start thinking “well, maybe the tests are all wrong.” (His results are too high for the doctor to be comfortable with a food challenge.) So, we keep reminding ourselves not to think that way and to stay as constantly vigilant as possible, until better tests are routinely available.

    • Well said, Rebecca. Since doctors can try to gauge the severity of an allergy based on their reaction to the skin-prick, I’d certainly take a severe reaction very seriously. It’s the very mild, barely-there reactions during the skin-prick tests that I think people have a harder time believing, because it really could be a false positive.

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