Updated

A daily dose of peanut powder could help some children who are allergic to peanuts, according to a pair of U.S. studies that confirm earlier findings, offering hope that a treatment could come soon.

In one study, teams at Duke University in North Carolina and the University of Arkansas for Medical Sciences gave 15 children tiny, but increasing, doses of peanut powder and compared them with eight children who got a placebo.

At the end of the year-long study, children given the treatment were on average able to tolerate 15 peanuts before having an allergic reaction.

"We started out literally at about a one-thousandth of a peanut and built that up over time," Dr. Wesley Burks of Duke, who helped lead the study, said in a telephone interview.

"When you take the daily dose it changes your immune system in a certain way and it raises the threshold of how much food it takes to cause a reaction," he said.

"Certainly the immune system changes while they're on the therapy and whether you can stop the therapy and it remains changed, that's the big question," Burks said.

In the second study, 12 children treated with peanut powder from age 32 months to 5 years old were monitored to see whether they could safely eat peanuts after the daily treatment stopped. The children were off the treatment for a month before they were given peanuts.

Nine of the 12 now have peanuts in their diets, the researchers reported at a meeting of the American Academy of Allergy, Asthma & Immunology in New Orleans.

The research builds on previous studies, in which children were able to tolerate the treatment for more than two years and four appeared to be freed of their peanut allergies.

"We are now trying to identify characteristics in those subjects who were able to stop the therapy to better understand who might be a good candidate for this treatment," Burks said in a statement released with the latest studies.

Burks said the results are encouraging but more research is needed before an effective treatment can be developed.

"I think, therapy we're still a few years away from," he said.

Allergies to peanuts or any other food occur when the body's immune system mistakenly sees compounds from the foods as invaders and creates antibodies to fight them.

Scientists say peanut allergies are on the rise worldwide, but nobody knows why. There is no cure and people with the condition must avoid even the tiniest amount of food containing peanuts.

The AAAAI estimates that 4 million Americans have food allergies, with tree nuts and peanuts, which are legumes, the most common. About 150 people die in the United States each year from food allergies, half from peanuts.