When we sneeze, why does it come in twos and threes?

Ben - I think it's just the conditions that created the sneeze don't go away, so you sneeze again. I'm not sure though. If anyone else has any ideas, please get in touch.Chris - I'm just trying to think whether, I mean, there was someone I know who used to have some congenital problem that used to make him sneeze excessively. I think that there can be a sort of miswiring effect in the nervous system and also certain brain diseases and maybe in brain tumors can cause compulsive unrepetitive sneezing.Ben - And we know that we have the photic sneeze response as well so perhaps there's something going on there whereby if you're exposed to bright light, you'll sneeze but then you're still exposed to bright light so there's no reason why you wouldn't sneeze again.Chris - Possibly. That's also genetic and we know that about one person in five has that. This is when you're in a dark room, you go into the bright lights of the streets and suddenly, wow you feel the sneezing fit come on. No one actually knows exactly why it happens so if you have an answer, let us know.