Saturday, April 05, 2003
Photic Sneeze Reflex
Let us speak of an odd little phenomenon that you have probably either observed in others or suffer from yourselves: the photic sneeze reflex. What happens when someone with this reflex steps into bright sunlight from a darkened or indoor environment? They sneeze, usually two or three times, then acclimate to the brighter light and stop sneezing.
I find this interesting because I have the photic sneeze reflex, and I know exactly where I got it from: my dad. This is an autosomal dominant trait, which means that if a sneezer has children, each child has a fifty percent chance of inheriting the reflex. The photic sneeze reflex is most often seen in Caucasians, but it can be seen in other racial groups too.
The cause is felt to be some sort of crossover in nerve feedback between the optic nerves and the trigeminal nerve nucleus in the midbrain, sort of like a short circuit. Many people refer to the reflex as being "allergic to sunlight," and while this is medically incorrect, having experienced it myself I can see why they say this: the intense light makes your nose tickle as if you'd just inhaled a bushel of cat dander.
Have you experienced the photic sneeze reflex? And wouldn't "Photic Sneeze Reflex" be a great name for a rock band? Send me your comments!