March 1, 2010 (New Orleans) -- An experimental treatment in which children with food allergies are fed tiny amounts of the very food to which they're allergic is allowing some kids with peanut allergies to enjoy peanut butter and some with egg allergies to eat scrambled eggs.
Three new studies suggest that the strategy, known as oral immunotherapy, can help kids build up tolerance to foods to which they are allergic.
Still, the ongoing studies are small and the children haven't been followed for that long, says Wesley Burks, MD, chief of pediatric allergy and immunology at Duke University Medical Center in Durham, N.C., who was involved in all three studies.
Don't try this at home, he cautions. Unless they're in the study, Burks gives the same advice to patients with food allergies that he always has given: avoid the offending food.
"The findings are promising but we're not there yet. Families shouldn't do this at home on their own as there is a chance a child could have a significant life-threatening reaction," Burks tells WebMD.
Studies in children with milk allergies also show promise, he says.
The studies were presented here at the annual meeting of the American Academy of Allergy, Asthma & Immunology (AAAAI).
Food Allergies on Rise
More than 12 million Americans, including 3 million children, have food allergies, for which there is no cure. Allergies to peanuts are among the most dangerous, accounting for 15,000 trips to the emergency department and nearly 100 deaths each year, according to the AAAAI.
Moreover, the number of people with peanut allergies doubled over a recent five-year period, from four in 1,000 people in 1997 to eight in 1,000 in 2002, according to Robert Wood, MD, director of the division of pediatric allergy and immunology at Johns Hopkins University School of Medicine in Baltimore.
Then, from 2002 to 2008, the figures shot up further, with 14 in 1,000 Americans now affected, he says.
"The goal of the new research is to cure the maximum number of people of food allergy while causing the least number of reactions," Wood tells WebMD.
Eating Peanuts With Impunity
In the first study, nine of 12 children with peanut allergies who swallowed small doses of peanut protein under a doctor's supervision daily for three to five years can now eat unlimited amounts of peanuts.
Four weeks after stopping the immunotherapy treatments, the children were challenged with a doctor-supervised test in which they were given increasing doses of peanut protein. They were able to eat the nuts without an allergic reaction, Burks says.
Not only did they not develop hives, wheeze, or exhibit other symptoms, but immune system changes suggest they've completely outgrown their allergies, he says.
The researchers looked at blood levels of immunoglobulin E (IgE), an immune system protein the body makes in response to allergens that tells you the likelihood that you're allergic.
IgE levels dropped in all the children, but they went down faster in the children who are now able to eat peanuts with impunity, he says.
Another 15 kids showed signs of desensitization, meaning that they could eat much higher doses of the peanut protein before having an allergic reaction.
"They're still on immunotherapy but their IgE levels aren't where we want them to be," Burks says.
In the study, the children were given tiny but escalating doses of peanut protein in the form of a powder sprinkled into applesauce or other food.
Other Nut, Egg Studies
In a second study of 25 children with peanut allergies, the researchers gave the peanut protein treatment to 16 children and placebo powder to the other nine.
After one year, the children were given the peanut challenge. The kids taking placebo had allergic reactions after consuming the equivalent of one and a half peanuts. Those in the treatment group could tolerate 20 peanuts before they developed symptoms.
The egg study involved 55 children aged 5 to 18. Forty were escalating daily doses of egg white powder and the rest got placebo powder.
None of the kids on placebo passed the egg challenge a year later, while 21 of the 40 could tolerate the full 5-gram dose without having a reaction. That's only about half an egg, but a few of the children are able to tolerate more and are eating scrambled eggs for breakfast, Burks says.