A patch that delivers small amounts of peanut protein could offer a treatment children with peanut allergies, a study has found.

A wearable skin patch could help children who are allergic to peanuts by delivering small doses of peanut protein, according to a new study.

The study, published in the Journal of Allergy and Clinical Immunology, found that nearly half of those treated with the patch for one year were able to consume at least 10 times more peanut protein than they were able to prior to treatment.

The biggest benefit came for those from 4 years old to 11 years old. Participants older than 12 didn't see as much of an effect, the study found.

The therapy works by training the immune system to tolerate small amounts of peanuts, said Dr Daniel Rotrosen, of the National Institute of Allergy and Infectious Diseases, part of the National Institutes of Health, which is funding the ongoing clinical trial.

"Other recent advances have relied on an oral route that appears difficult for approximately 10 to 15 per cent of children and adults to tolerate," Rotrosen said.

While the trial found the immunotherapy treatment to be "potentially effective," it cautioned that the study is limited. Further investigation is needed to find out if "the modest clinical changes noted will be enhanced after a longer duration of therapy," the study said.

The Viaskin Peanut patch hasn't been approved by the US Food and Drug Administration.