July 30, 2012

Hope for Beating Egg Allergy

Teenager holding eggs.

Giving small daily doses of egg powder to children with egg allergy could pave the way to letting them eat the food safely, a new study finds. This would make life easier on kids whose only current option is to stay away from all foods that contain eggs.

Egg allergy is one of the most common food allergies in children. There's no treatment other than completely avoiding the food. That's tough for children, parents and caregivers; eggs can lurk in everything from marshmallows to salad dressing. And the stakes are high. Children who are allergic to eggs can have reactions ranging from hives to anaphylaxis, a life-threatening condition with symptoms that include throat swelling, a sudden drop in blood pressure, trouble breathing and dizziness.

One possible way to help people with food allergies is oral immunotherapy. In this still-experimental approach, patients eat gradually increasing amounts of the food they're allergic to. A research team led by Dr. A. Wesley Burks at the University of North Carolina and Dr. Stacie M. Jones at the University of Arkansas for Medical Sciences tested oral immunotherapy for children who are allergic to eggs. The study was funded by NIH's National Institute of Allergy and Infectious Disease (NIAID), National Center for Research Resources (NCRR) and the National Center for Advancing Translational Sciences (NCATS).

The researchers recruited 55 children, ages 5 to 18, who were allergic to eggs. Forty of the participants ate daily doses of raw egg-white powder. The others received cornstarch as a placebo. Researchers increased the dose every 2 weeks until the children on oral immunotherapy were eating the equivalent of about one-third of an egg every day.

At 10 months, the participants went into the clinic, where they were “challenged” with increasing doses of egg-white powder and watched closely for symptoms. As reported in the July 19, 2012, issue of the New England Journal of Medicine, more than half of the children who had been eating egg powder daily passed the challenge, with no allergic reaction or only minor symptoms. A year later, 30 children passed a challenge with an even larger dose of egg powder. In contrast, none of the children in the placebo group passed the challenge.

Those 30 children stopped oral immunotherapy and were told to avoid all eggs for 4 to 6 weeks. Then they faced another challenge: a dose of egg powder and a whole cooked egg. Most kids had allergic reactions, but 11 passed the test and were allowed to eat as many eggs or egg-containing foods as they wanted in their normal diets. A year later, those children reported they still had no problems eating eggs.

The study suggests 2 ways that egg oral immunotherapy could help children. First, while they were eating the daily dose of egg powder, most of the children could safely eat eggs. Second, a small group of children—about 1 in 4—were able to eat eggs even after the daily oral immunotherapy ended.

"Although these results indicate that oral immunotherapy may help resolve certain food allergies, this type of therapy is still in its early experimental stages and more research is needed," says Dr. Daniel Rotrosen, director of NIAID's Division of Allergy, Immunology and Transplantation. "We want to emphasize that food oral immunotherapy and oral food challenges should not be tried at home because of the risk of severe allergic reactions."

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Reference: N Engl J Med. 2012 Jul 19;367(3):233-43. PMID: 22808958