July 18, 2012 -- Exposing children with egg allergies to egg in a carefully controlled setting can dramatically reduce and even eliminate potentially life-threatening allergic reactions for some children, new federally funded research shows.
About 4% of children in the U.S. have food allergies, according to the CDC.
At present, the only good way to avoid reactions to allergic foods is by strictly avoiding them.
But an approach known as oral immunotherapy, which seeks to slowly desensitize the body to the allergic food, is showing promise in early trials.
Egg Therapy Still Experimental
In a new study appearing in the New England Journal of Medicine, children who were allergic to eggs were given small but increasing doses of egg white powder for 10 months, followed by several years of maintenance dosing.
More than a quarter of the children who were treated with the egg white powder lost their allergic reactions altogether after two years.
"These children went from having serious allergic reactions after a single bite of an egg-containing cookie to consuming eggs with minimal or no symptoms," says Robert Wood, MD, who directs the allergy and immunology department at Baltimore's Johns Hopkins Children's Center.
Although results from the oral immunotherapy trials are encouraging, Wood warns that the treatment is still highly experimental.
"We are still very much in the research phase," he tells WebMD. "There are still many things to be worked out before this treatment is ready for use in the practice setting."
1 in 4 Kids Passed Egg Challenge
This study is one of several oral immunotherapy trials conducted through the National Institutes of Health-funded Consortium of Food Allergy Research.
In it, 55 children ranging in age from 5 to 11 with egg allergy received either carefully controlled doses of egg white powder (40 participants) or cornstarch powder (15 participants), which served as a placebo. Children with a history of a severe allergic reaction to egg, such as drop in blood pressure, were not included in the study.
The egg dose was gradually increased over 10 months until the children were given the egg white powder equivalent of about a third of an egg every day, according to the researchers.
Three oral food challenges were conducted at 10 months, 22 months, and 24 months, with children exposed to larger doses of egg white powder. As part of the 24-month challenge, participants were also given one real egg to eat.
After 10 months, just over half (55%) of the children treated with the egg therapy passed the challenge, while none of those in the placebo group did.
At 22 months, 75% of the children in the egg treatment group passed the food challenge. Those that passed the 22-month challenge stopped egg therapy and avoided eating anything with egg for four to six weeks.
But most lost the tolerance they had achieved after stopping the daily egg exposures, suggesting that continuing the therapy for a longer period of time is important for maintaining tolerance.
Case in point: At 24 months, only 28% of the remaining egg therapy group passed the challenge -- but, these children were all eating eggs without problems at 30 and 36 months.
Some Could Not Tolerate Treatment
Most children with food allergies show symptoms by age 3, but many outgrow these allergies by the time they reach school age.
For those who don't, food allergies can persist into early adulthood and may even last a lifetime.
Researcher A. Wesley Burks, who chairs the Department of Pediatrics at the University of North Carolina, Chapel Hill, tells WebMD that an important goal of future research is learning how to identify who will and will not outgrow food allergies early on and who will benefit from oral immunotherapy.
He adds that the fact that four of the children in the study had to drop out because of allergic reactions suggests that the therapy will not work for everyone.
"I think there is probably a small percentage of kids who will not tolerate a treatment like this, and we need to learn how to identify them early on," he says. "But for kids who do respond, this treatment can be life altering."