Egg in tiny doses curbs allergy

Exposure to increasing amounts of egg every day over two years can seemingly rid some children of an egg allergy, a new study finds. This gradual introduction into the diet appears to re-train the immune system, allowing some sensitive children to handle egg proteins even after treatment ends, researchers report in the July 19 New England Journal of Medicine.

Many other children in the study developed an ability to cope with small amounts of egg without a serious reaction — but only while being treated. That finding could nonetheless have benefits.

“If you’re a parent who has a child who’s allergic, there is much more interest in providing protection from an accidental reaction” than in having the child gain a new food group, says study coauthor Wesley Burks, a pediatric immunologist at the University of North Carolina in Chapel Hill. “If you can give them something to protect them, that’s what a parent wants.”

Burks and a U.S. team identified 55 children ages 5 to 11 with egg allergies, confirmed by skin-prick tests, medical history and the presence of antibodies to egg protein. All of them got an unmarked powder added to their food daily. Forty kids were randomly assigned to receive the egg treatment and 15 got cornstarch as a control. The treatment amounted to a few grains of powdered egg white on the first day and gradually grew to the equivalent of one-third of an egg. 

After 22 months, 30 of the 40 children getting the treatment were able to consume 10 grams of powdered egg white without having a visible reaction, such as wheezing. Five of the 40 did have a reaction to the egg test, as did all children in the placebo group. Another five children who had allergic reactions to the initial treatment dropped out of the study early on.

Four to six weeks after stopping treatment, the children who didn’t react to the egg test got tested again, this time with 10 grams of egg white powder plus a cooked egg. Eleven passed that test. A year later, 10 of them were eating eggs at will.

“I think this is very promising,” says Mary Beth Bollinger, a pediatric allergist at the University of Maryland School of Medicine in Baltimore. One of the remaining challenges will be to identify beforehand which children are the most likely to benefit from the treatment. Such predictions may emerge from tests of their immune cells and proteins, she says.

In this study, blood tests of kids whose treatment succeeded showed an accumulation of positive immune changes during treatment, particularly of factors implicated in the inflammation that marks a serious allergic reaction. Whether those changes are permanent is unknown and will be addressed in future work, Burks says.

Overall, about 10 percent of children given this type of oral treatment for egg, peanut or milk allergies — including roughly that fraction in this study — have reactions early and drop out, Burks says. “For a small group of kids, this isn’t the right therapy.”

And the study’s results do come with a warning: Don’t try this at home. The Food and Drug Administration would need to approve an oral treatment for clinical use.

“This study does offer hope that in the next few years a treatment could be developed,” Burks says, “but we’re not there yet.”