Achoo syndrome is nothing to sneeze at

Up to 35% of people have sneezing reflex triggered by bright light, one study says

- Leow Wen Xuan

It may be April Fool's Day, but Achoo syndrome is no joke.

Autosomal dominant compelling helio-ophthalmic outburst syndrome, ostensibly named for its backronym, refers to a mysterious sneezing reflex in some people that is triggered by bright light, usually after coming out from a dark environment.

In severe cases, some studies showed that exposure to bright light can cause more than 40 consecutive sneezes, said Dr Tan Zhibin, an associate consultant at the Department of Neurology at the National Neuroscience Institute.

Dr Tan said sudden uncontrollable sneezing can be dangerous for pilots and drivers who are exiting a dark tunnel, though there have not been documented cases. Other researchers have brought up the dangers of the reflex to baseball outfielders and high-wire acrobats.

The exact mechanism behind the reflex has not been confirmed.

However, there have been some theories.

A 2010 Swiss study published in a scientific journal by the Public Library of Science found neural differences between photic - or lightstimulated sneezers and nonphotic sneezers by measuring their brain activity.