July 19, 2012

Exposure To Eggs Can Help Fight Egg Allergies

Lee Rannals for redOrbit.com - Your Universe Online

A new study suggests that children who have egg allergies may benefit by just being exposed to the very food they are allergic to.

Researchers treated 35 children with egg oral immunotherapy (OIT) and found that eleven of them experience long-term elimination of egg-related allergic reactions.

The rest of the children who were exposed to eggs were able to tolerate higher doses of egg, with only mild or no symptoms. The study originally had 40 participants, but five of them dropped out of the study due to allergic reactions related to treatment.

The researchers said that having a higher threshold of tolerance is an important therapeutic endpoint because it can protect against serious allergic reactions from accidental or incidental exposures, and give patients and parents a better peace of mind.

"More than a quarter of the children in our study lost their egg allergies altogether, but we also saw dramatic improvements in those who didn't, which in and of itself is an important therapeutic achievement," Robert Wood, M.D, director of allergy and immunology at Johns Hopkins Children's Center, said in a press release.

"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."

During the study, 55 children received escalating doses of egg-white powder or a cornstarch placebo for 10 months. Thirteen of the 15 patients treated with the placebo failed an oral food challenge that required children to eat under medical observation 5 grams of egg protein.

After the 10-month buildup, the researchers found that 22 children treated with egg whites were able to consume 5 grams of egg protein, 14 of which had no symptoms. All 35 children continued to consume small doses of egg whites daily for 22 more months.

At the end of the 22-month cycle, the team had the children eat 10 grams of egg whites, and 30 out of 35 of the children passed the food challenge. Those children who passed were then asked to cease all egg consumption for four to six weeks, and underwent a final food challenge.

Eleven of the children who were egg "abstinent" were still able to tolerate 10 grams of egg protein without any symptoms, and were considered completely cured of their allergy.

"The intent of this study was to develop a new treatment for egg allergy because we really have no treatment now, other than avoidance," Wesley Burks, MD, Curnen Distinguished Professor and Chair of the UNC Department of Pediatrics and the study's lead author, said in a press release. "This study gives us hope that we're closer to developing a treatment." Burks added that the results may also have implications for treating other food allergies, such as allergies to milk or nuts.

The researchers conducted a follow-up interview over the phone a year later and found that 11 of the children reported eating eggs and egg-containing products without symptoms as frequently or as infrequently as they chose.

The researchers said that the fact that most children lost some of their tolerance after a month of abstinence underscores the importance of daily exposure to an allergen to maintain tolerance.

About 4 percent of children in the U.S. are estimated to have food allergies, and nearly 3 percent of children have evidence of egg allergies, the researchers said.

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

The study was published in the New England Journal of Medicine on Thursday.