Many people afflicted by photic sneezing may not realise that the cause of their tickly nose is not hayfever or dust, but is actually triggered by the bright light of the summer sun.
Photographer Pete Jelliffe, pictured at the top of the page, suffers from photic sneezing. He said: "I sneeze twice every time I walk out into bright sunshine. It's so predictable I am able to photograph my self mid-sneeze."
What is Photic Sneezing?
The condition—scientifically known as 'Autosomal Cholinergic Helio-Ophtalmologic Outburst' or 'ACHOO' syndrome—affects 18-35% of the population according to PubMed.gov.
According to clinical tests, sneezes appear to be triggered by a sudden increase in the intensity of light rather than by any particular wavelength of light. They occur between two and 15 seconds after being exposed to the change in light.
What Causes Photic Sneezing?
Scientists are still trying to discover exactly what causes the sneezes. Two of the theories put forward are:
- When going into bright light the subject's eyes produce tears which go down into the nose and trigger a sneeze.
- Irritation in the nose is sensed by the trigeminal nerve, which is close to the optic nerve. As the optic nerve takes in the sudden bright light, it tells the brain to constrict the pupils, but some of the electrical signal is sensed by the trigeminal nerve and mistaken as an irritant in the nose, and a sneeze is produced.
Scientists believe that studying photic sneezing could help them understand other conditions such as epilepsy or migraines. Although the conditions are unrelated, epileptic seizures are sometimes triggered by flashing lights, and migraines often bring on a sensitivity to light.
Some scientists hope that by finding out more about photoc sneezing they can identify a gene which may shed more light on the visual pathway.
Is Photic Sneezing Dangerous?
In general, photic sneezing is no more dangerous than normal sneezing, but it could be a cause for concern in pilots or drivers. Pilots may find themselves sneezing after emerging from a cloud, or if the sun suddenly comes out, while drivers could sneeze after going through a long tunnel.
Is There A Cure?
There is no specific cure for photic sneezing, although most sufferers will say it is a nuisance rather than a debilitating condition. However, wearing sunglasses will prevent the sneezing as it mitigates the changes in light levels.
Sources:
- The photic sneeze reflex as a risk factor to combat pilots
- An EEG Study Identifying Neural Bases of Photic Sneezing
- Pete Jelliffe
Pam Griffin - Pam Griffin is a journalist working in Shropshire, UK. She is interested in first aid, singing and playing music, history, and ...
