New peanut allergy tests points to great over-diagnosis in kids

New research finds that we may be over-diagnosing, and over-treating, food allergies in kids.

According to researchers at Stanford University, five to 12 percent of kids test positive for allergies to milk, shrimp, peanuts or eggs, but less than three percent actually have allergic reactions to those foods.

Deborah Kotz, a reporter for the Boston Globe, said a new blood test, the uKnow Peanut Molecular test, is given to kids suspected of having peanut allergies. It turns out, with the new test, doctors can determine they do have allergies, but more likely to a birch pollen, rather than peanuts.

“It makes their mouth very itchy when they eat not only peanuts, but when they eat other kinds of foods like raw fruits and vegetables that have similar proteins to birch polen,” Kotz said. 

The new test has revealed that kids who were religiously avoiding peanuts should actually be taking something like Benadryl, she said.

But that’s not to take away from children who legitimately do have a peanut allergy.

“There is a distinction between pollen allergies — ragweed, grass — the types of allergies that make us sneeze, that make our eyes water, and then there are the food allergies, which can not only cause sneezing and coughing, it can cause us to become very nauseous, it can cause breathing difficulties, and some kids (can go) into anaphylaxis where they could die from eating a certain food,” Kotz said.

That danger has made treating food allergies extremely difficult. Whereas pollen allergies can be treated with shots, food allergies have always been treated with an admonition to completely avoid the food.

“They’re just now starting to develop some treatments to see if they can get kids over them. Because it’s been far too dangerous to even try to expose them to certain things they’re allergic to,” Kotz said.

One of those tests involved a child being exposed to eggs, gradually, over two years and with a doctor’s supervision, to try and get them to build up a tolerance to the allergies.

Kotz says this required careful planning on the part of the researchers — not something that a typical, community-based allergist should try.

“They were really trying to include only those kids who’d had some sort of mild, moderate allergic reaction to eggs in the past,” Kotz said. “Hives, an itchy throat, a little bit of swelling, but nothing too life-threatening.”

There’s also been a huge shift in thinking by the American Academy of Pediatrics, in terms of how to keep kids from developing bad allergies. Originally, it was thought that exposing kids to these sorts of allergens at an early age would give them allergies.

But a British study found exactly the opposite, and the shift is on.

“What happens is the immune system does an imprinting as a baby gets older and starts to really fully develop. When it has those exposures to those allergens, it learns to recognize them not as foreign dangerous invaders,” Kotz said, “but as a harmless substance that’s a food that should be handled by the body.”