Normal bacteria living on the skin trigger a pathway that helps prevent inflammation when we get hurt, the US team discovered.
A spokeswoman for Allergy UK said there was a growing body of evidence that exposure to germs was a good thing.
"Rates of allergy have tripled in the UK in the last decade. One in three people now has some kind of allergy.
"Some of this might be that people are better informed. But a lot of it is genetic as well as down to our environment," she said.More can be found on BBC News - Dirt can be good for children, says scientists
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