sneezing due to sunlight

Something in the region of 10% of the population can relate to sneezing due to sunlight. For the other 90% this probably seems a little hard to grasp and indeed many of those people who find themselves sneezing when out in the sun, are often laughed at and told the sneezing is a reaction to pollen and it is just a coincidence that they sneeze outside. Well Scientists have now recognised the condition and have actually given it an official name, and you have to admire their sense of humour, as they‘ve given this form of sneezing the name: Autosomal Dominant Compelling Helio-Ophthalmic Outburst Syndrome, or ADCHOO! A small portion of the 10% sufferers will sneeze every time they look toward the sun; for the majority, the sunlight merely helps a sneeze along. It is believed that the cranial nerves run very close to one another inside the head. When a stimulus as bright as the sun strikes the optic nerve through the eye, it stimulates a reflex reaction in the nearby olfactory nerve, causing the sneeze. The condition is probably better known as the photic sneeze reflex. It occurs only after someone has been adapted to the dark for at least five minutes, as even photic sneezers' pupils will adjust normally (without triggering a sneeze) if they go in and out of bright light for short periods of time. So the real mystery is why an extended period of darkness makes a difference. If you do find yourself sneezing when first encountering the sunlight, one of your parents will be to blame because it is an inherited trait.