Every time I leave a building and walk into the out-of-doors, I sneeze. I'm sure it has something to do with the sun. Sometimes just looking up at the sun (yes, I know: not directly) makes me sneeze. Most people I know don't have this problem (I actually rather enjoy it). Why does the sun make me sneeze? More importantly, why does the sun make me sneeze when most other people have no reaction to it other than to burn and peel?
We at Ask Gothamist HQ are known for our incredibly loud, violent sneezing, which often amuses our friends, coworkers, and significant other to no end. But we've never had a sneezing fit in reaction to sunlight. We thought perhaps this sneezing in sunlight business was an old wives' tale. But it turns out that you probably have something called Photic Sneeze Reflex. According to Medicinenet.com, this condition is "characterized by nearly uncontrollable paroxysms of sneezing provoked in a reflex fashion by the sudden exposure of a dark-adapted subject to intensely bright light, usually to brilliant sunlight. The number of successive sneezes is usually 2 or 3, but can be up to about 40." And according to The Straight Dope, only about one-sixth to one-quarter of the population is affected by the Photic Sneeze Reflex, which seems to be genetic.
As to what actually causes this sneezing reaction to sunlight, Wikipedia says "the probable cause is a congenital malfunction in nerve signals in the trigeminal nerve nucleus. The fifth cranial nerve, called the trigeminal nerve, is apparently responsible for sneezes. Research suggests that some people have an association between this nerve and the nerve that transmits visual impulses to the brain. Overstimulation of the optic nerve triggers the trigeminal nerve, and this causes the photic sneeze reflex." In other words, your brain's wired a little differently than the rest of us non-sunlight-sneezers.
Luckily for you, there's a very simple solution to your problem: Wear sunglasses.
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