Scientists have taken a step closer to helping children and teenagers with peanut allergies.

Such an allergy can have a big impact on a person's life, due to the potential inclusion of peanuts in many foods. This is currently the most common cause of severe and life-threatening allergic reactions that are related to food.

The only way to avoid a reaction is to avoid foods containing peanuts, however accidental consumption is relatively common.

Now UK scientists have found that children and teenagers could benefit from treatment with oral immunotherapy (OIT) - this involves the consumption of peanut protein in increasingly larger amounts on a regular basis in order to build up tolerance.

According to the results of a phase 2 trial, after six months of OIT, almost nine in 10 children could safely tolerate the daily ingestion of 800mg of peanut protein - this is equivalent to around five peanuts.

This was at least 25 times as much peanut protein as the children could tolerate before the OIT.

"This treatment allowed children with all severities of peanut allergy to eat large quantities of peanuts, well above the levels found in contaminated snacks and meals, freeing them and their parents from the fear of a potentially life-threatening allergic reaction. The families involved in this study say that it has changed their lives dramatically," said study leader, Dr Andrew Clark, of Cambridge University Hospitals.

In the first part of this trial, 99 children aged between seven and 16 were randomly assigned to receive 26 weeks of OIT, or to simply try to avoid peanuts. The children had varying degrees of peanut allergies.

All of the children then underwent a challenge in which they consumed increasing amounts of peanut protein under medical supervision in order to determine at what point they experienced an allergic reaction.

In the second part of the trial, those who had previously avoided peanuts also underwent 26 weeks of OIT, followed by another food challenge.

After six months of OIT, six in 10 of the children who had received the therapy in the first phase managed to tolerate a daily dose of 1,400mg of peanut protein - around 10 peanuts - compared with none of the children in the control group.

After the second phase, five in 10 were able to tolerate 1,400mg. Ten peanuts is unlikely to be consumed accidentally, the scientists noted.

While one in five children undergoing OIT reported adverse events, most of these were mild, such as oral itching.

"We found that OIT is well tolerated and provides protection in most children with peanut allergy in this age group by raising the reaction threshold. This large study is the first of its kind in the world to have had such a positive outcome, and is an important advance in peanut allergy research," commented the study's co-author, Dr Pamela Ewan.

However, she emphasised that OIT is not a treatment people should try on their own.

"It should only be done by medical professionals in specialist settings," she insisted.

Meanwhile experts have said that while these results are promising, OIT is still years away from routine clinical use.

Details of these findings are published in the medical journal, The Lancet.