Answered by Lydia Samuel
This is a really interesting question as it is a common phenomena but doesn’t seem to have much scientific explanation. Both my husband and son experience this every time they step into bright sunlight so I have noticed it too, though I don’t experience it myself. It has a name - the photic sneeze reflex or photoptarmosis to medical types. The condition affects 18–35% of the population, but scientists don’t exactly know what causes it. Photic sneezing also has the brilliant acronym Autosomal dominant Compelling Helio-Ophthalmic Outburst (ACHOO) syndrome. Amazingly sneezing caused by sunlight was first mentioned by Aristotle in around 350BC so it is not a new phenomena! The photic sneeze reflex seems to be caused by a change in the intensity or brightness of light rather than a specific wavelength of light. You are apparently more likely to suffer from it if you are female and Caucasian.
This is a really interesting question as it is a common phenomena but doesn’t seem to have much scientific explanation. Both my husband and son experience this every time they step into bright sunlight so I have noticed it too, though I don’t experience it myself. It has a name - the photic sneeze reflex or photoptarmosis to medical types. The condition affects 18–35% of the population, but scientists don’t exactly know what causes it. Photic sneezing also has the brilliant acronym Autosomal dominant Compelling Helio-Ophthalmic Outburst (ACHOO) syndrome. Amazingly sneezing caused by sunlight was first mentioned by Aristotle in around 350BC so it is not a new phenomena! The photic sneeze reflex seems to be caused by a change in the intensity or brightness of light rather than a specific wavelength of light. You are apparently more likely to suffer from it if you are female and Caucasian.