I don't know, but personally I would not require a child to stay home for this. I might suggest they talk to their doctor about it, but the doctor will probably just say it's a cold and not do much. Some kids just seem to have runny noses all the time. There's been some really nasty bugs going around and most of my daycare kids had runny noses for more than a month (although thankfully they are all fine now). I think as long as there is no fever and the child is not acting sick, there's not much you can do. I think of it as just one of the unpleasant parts of the job, wiping noses and cleaning bums go hand in hand.