Children may grow out of allergies to peanuts, researchers say.
Eating peanuts can cause a potentially fatal reaction
And the team which carried out the study suggests occasionally eating peanuts may help children maintain their tolerance of the nut, to prevent a recurrence of the allergy.
They say children with a peanut allergy should be re-tested every two years to monitor their reactions to peanuts.
Researchers tested 80 children aged between four and 14, who had previously been diagnosed as having a peanut allergy.
Each child ate a product with peanuts and was then watched to see if they showed any signs of an allergic response, such as a rash, coughing, breathing difficulties or vomiting.
More than half of the children ate the foods without experiencing an allergic reaction.
Some of them had previously had a reaction in the same test. Others had a history of severe, life-threatening reactions.
Dr Robert Wood, a paediatric allergy specialist at Johns Hopkins Children's Center in the US, who carried out the study, said: "Although we once thought peanut allergy was a lifelong problem, we now believe certain children, namely those with low levels of allergy antibodies, may outgrow it.
"Because of these findings, and the tremendous burden peanut allergies can cause for children and their families, I recommend that children with peanut allergy be retested on a regular basis, every one or two years."
He added: "Although recurrence of peanut allergy appears to be uncommon, we believe the risk of recurrence may be higher among those who do not consume enough peanuts to maintain their tolerance level.
"However, further study is needed to determine whether this is true, and whether 'outgrowers' should be encouraged to eat a certain amount of peanut."
Dr Wood said parents should always talk to their doctor before giving peanuts to a child who may have outgrown the allergy.
David Reading, head of the UK's Anaphylaxis Campaign, told BBC News Online: "Parents of children with peanut allergies need to be aware of this possibility.
"They need to note down every time their child has a reaction.
"If the child does not have a reaction for some time, they should consider the possibility that the child may have outgrown it."
He said parents should then ask to be referred to a specialist clinic for tests to check whether or not the child was still allergic to peanuts.
But he warned: "When someone is thought to have outgrown their allergy it would still be prudent to maintain access to emergency medication until the child has retained a tolerance for one to two years."
The research is published in the Journal of Allergy and Clinical Immunology.