Question: Why do we sneeze?

Darren Logan answered on 13 Mar 2012:

We sneeze for a few reasons.

Firstly, if something tickles our nose hairs we tend to sneeze. This is because we don’t want stuff up there, and its our body’s way of getting it out. Secondly, if we have an infection in our nose (such as a cold or a virus) then we will sneeze. This is because infection leads to inflammation which causes the release of histamines. Histamines irritate the nerves in the nose which tells the brain to sneeze.

However some people sneeze for other strange reasons. There is something called the “photic sneeze reflex” which means you sneeze when you see really bright light. No-one really knows why this happens but some people think its due to the nerves that carry the light signal and the nerve the controls the sneezing signal being very close together in your head. Whats weird about this is that it runs in families, so we think there may be some genes that control it.

Another weird type of sneezing is something called “snatiation” – which means sneezing when you have a full stomach just after eating. This too seems to be genetic, but no one knows how it works.