Studies Predict Odds of Outgrowing Nut Allergies

Children who develop an allergy to nuts may not continue to have that allergy later in life. Results from the most recent nut allergy studies are helping doctors predict which kids have the best odds of beating common food allergies.

STEVE INSKEEP, host:

You know, a lot of kids who grew up with allergies to peanuts, walnuts and pecans are learning they can now eat those foods. Results from the most recent nut allergy studies are helping doctors predict which kids have the best odds of beating common food allergies. NPR's Allison Aubrey reports.

ALLISON AUBREY reporting:

Back in the mid-1990s, concern over nut allergies spiked. Airlines were sued over serving peanuts, and schools declared nut-free lunch tables. Mother Lisa Fitzhugh didn't think much of the fuss until one day in the spring of 1994, when she gave her 18-month-old daughter, Erin, a bite of walnut.

Ms. LISA FITZHUGH (Parent): And in about three minutes of eating it, her face completely puffed out, and her eyes were shut, and I knew something was really wrong.

AUBREY: Spoonfuls of Benadryl halted the reaction and to make sure it didn't happen again, Fitzhugh assumed she'd never be able to serve nuts again. But then she took her daughter to see an allergist at Johns Hopkins University, who administered a series of blood tests. They're more comprehensive than simple skin prick tests.

Dr. DAVID FLEISHER(ph): When you do the blood tests, you actually get a number on a scale from negative to greater than a hundred.

AUBREY: The higher the number, the more intense the allergy. Erin's results came back surprisingly low, under five for peanuts, walnuts and pecans.

Dr. FLEISHER: You can actually follow that level. We usually do it on an annual basis. And you can see if that number's going up or it's going down, and based on when it's going up or how far it's going up and how quickly it's going down, you can predict when they may outgrow it or whether they will outgrow it at all.

AUBREY: In Erin's case, Dr. David Fleisher advised avoiding nuts for a few years and then retesting. That's because childhood allergies tend to peak between ages three and four and can then begin to wane at five. So just before Erin entered kindergarten, her mother brought her in for another set of blood tests, which are designed to measure something called IgE. This is the antibody the body produces when it's exposed to an allergen.

Ms. FITZHUGH: The peanut was gone.

AUBREY: The tests indicated she'd outgrown the peanut allergy entirely, and to be certain, doctors brought Erin in for a day of controlled snacking. For several hours, they gave her bits of peanut-laden foods and watched for a reaction. When it was clear that she was fine, Erin was sent home and told to start eating as many peanuts as she liked. It was advice that made her mother very nervous.

Ms. FITZHUGH: You want to protect your child, and you can't believe that there's--to protect your child, now the doctor has said she can have it and you are supposed to give her peanuts, what could have killed her before. It's hard for a parent.

AUBREY: Outgrowing peanut and tree nut allergies is turning out to be fairly common. Children who start out with a score of five or below on the IgE blood tests have more than a 50 percent chance of tolerating nuts later in life. Dr. Robert Wood of Hopkins says what's surprising in the research is that this seems to hold up even in children who have had severe allergic reactions early in life.

Dr. ROBERT WOOD (Johns Hopkins University): We thought that those that had had a severe anaphylactic reaction would automatically be less likely to outgrow their allergy, and that's turned out to not be the case. So on the initial reaction, whether you've had a mild, moderate or severe reaction actually does not have any bearing on your chance of outgrowing the allergy.

AUBREY: So it's clear that parents can't make any assumptions about the progression of their kids' food allergies.

Ms. FITZHUGH: And that's why staying with the doctor, testing, getting the correct information and staying consistent is absolutely the key.

AUBREY: Hopkins physician Elizabeth Matsui says the latest research does not suggest that schools should give up on peanut-free tables.

Dr. ELIZABETH MATSUI (Johns Hopkins University): We still need to be very vigilant about protecting the children who are still peanut and tree nut allergic.

AUBREY: Given the high number of parents who report to school nurses that their kids are allergic to peanuts, it's clear that some are basing their assessment on old assumptions, instead of up-to-date test results. Allison Aubrey, NPR News, Washington.

INSKEEP: And that's our personal health news for this morning.

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