Peanut Allergy? A Cure May Be on the Way
By Amanda Gardner
SUNDAY, Feb. 28 (Health.com) — If your children are allergic to peanuts, you may not have to live—and eat—in fear much longer. Gradually building up a tolerance to peanuts and other foods may prevent dangerous allergic reactions, new research suggests.
Eating very small amounts of peanuts over a long period of time can desensitize children to the nuts, lessening the risk of a life-threatening emergency, according to a pair of studies presented this week at the annual meeting of the American Academy of Allergy, Asthma & Immunology in New Orleans.
Don’t try this at home, however. Even small amounts of peanut products can be fatal for some people, so the desensitization process is too risky to be done without a doctor’s supervision. Roughly 1.5 million people in the United States are allergic to peanuts, and as many as 100 die each year after ingesting the nuts and going into shock.
The good news is that, according to a third study presented at the meeting, the same technique could be used for another common problem, egg allergy.
Although the study results are promising, the treatment isn't ready for widespread use, and it's unclear how soon that will be, experts say.
"It gives us hope that in another few years we'll have a treatment that can go into the clinic," says Wesley Burks, MD, the chief of pediatric allergy and immunology at Duke University Medical Center, in Durham, N.C., who was involved in all three studies. "But we're not there yet."
The treatment, known as oral immunotherapy, exposes an allergic child to increasing amounts of peanuts or egg over a period of years. "You're fooling the body into accepting amounts of the substance without reacting," explains Amal H. Assa'ad, MD, the director of the food allergy clinic at Cincinnati Children's Hospital.
The ultimate goal of any treatment would be to achieve tolerance, the point at which the body permanently stops reacting to the food, Dr. Assa'ad says.
"There's still a lot to learn," she adds. "It looks like it might work, but we don't know if it's going to work on everybody, and the side effects are plenty." Potential side effects of immunotherapy include sneezing, itchiness, and nausea, in addition to the risk of anaphylactic shock (a potentially fatal drop in blood pressure) and other serious reactions.
Next page: Study results "impressive"
In the first peanut study, 29 allergic children received either a placebo or small doses of peanut flour for 12 months, after which the children were given small amounts of peanuts. The children who received the immunotherapy were able to tolerate about 15 peanuts, while the children who got the placebo started to react after about one peanut.
In a follow-up study, 9 of 12 children who received peanut immunotherapy for up to five years achieved tolerance. Four weeks after stopping the immunotherapy, they were able to eat peanuts without an allergic reaction.
The study results are "impressive," says Jonathan Field, MD, the director of the allergy and asthma clinic at New York University's Langone Medical Center. Until recently, Dr. Field says, doctors did not think that immunotherapy could be used to prevent food allergies.
A treatment for peanut allergy is the "holy grail," he adds.
The results in the egg study are also promising. Compared to those on a placebo, children who received immunotherapy for about 3.5 years could eat far more egg without experiencing a reaction. (The amount of egg they could tolerate was relatively small, however: only about 5 grams, or one-eighth of a hard-boiled egg.)
"This appears to be quite a viable treatment for a large subset of patients. It's not without risk, but the risks, when managed by a well-trained allergist, are moderate," says Stephen C. Dreskin, MD, a professor of medicine at the University of Colorado Denver. "It's just a matter of how quickly this will be incorporated into the practices of allergists." That could occur within a year, Dr. Dreskin predicts.
Dr. Burks and his colleagues are continuing their research to determine whether tolerance can be achieved in more patients. If they succeed, the treatment probably will not require approval from the U.S. Food and Drug Administration, he notes.
One drawback of oral immunotherapy is that it requires an extended commitment. Only the most motivated and conscientious patients are likely to make it through a multi-year immunotherapy regimen, says Dr. Dreskin.
And because of the risk of anaphylactic shock (and even death), immunotherapy is inherently risky. Initially, the treatment may have to take place in an intensive care unit, Dr. Field suggests.
Scott H. Sicherer, MD, a co-author on the egg study and a professor of pediatrics at the Jaffe Food Allergy Institute of Mount Sinai School of Medicine, in New York City, agrees. "There are a number of things that have to be worked out before this can be used in clinics across America,” he says.