A US schoolgirl can't stop sneezing.

Lauren Johnson, 12, has baffled doctors with a bizarre medical condition which means she sneezes continually - up to 16 times a minute.

She said: "It's frustrating a lot. It's pretty hard. I have to be physically exhausted before I can go to sleep because I just sneeze and sneeze. Eventually I can hold off for a couple of seconds and go to sleep."

After visiting numerous medical experts and hypnotherapists, Lauren's mother Lynn - who lives with her daughter in Virginia - is running out of ideas to help her daughter.

Test results have never shown abnormal medical or psychological results.

Lynn said: "Their hearts go out to her. They really want to help her. I just don't think anybody knows how."