Some people sneeze suddenly and unintentionally when they step out of dark rooms, the others make fun of it. Often sun sneezing is misunderstood as a symptom of sun allergy. Aristotle already considered this as ACHOO syndrome today - from his long English name: ACHOO syndrome (Autosomal Dominant Compelling Helio-Ophthalmic Outbursts of Sneezing) - or Photonic Sneezing.
Sunlight and other triggers
The photic sneeze reflex can be triggered by sunlight, but also by other sources. There are varying degrees of expression, with 17 to 35% of the world population being spread, with women being more affected than men.
Since time immemorial, people have been wondering what causes the Photic Sneeze - Aristotle blamed heat, Francis Bacon thought spewing cerebral fluid was the enigmatic solution - and even today, ACHOO syndrome can not be explained clearly. A clinical diagnosis for the ACHOO syndrome does not exist until today.
If both you and close relatives always sneeze when you leave the house on a beautiful sunny day, you can assume that you have it.
ACHOO Syndrome - Causes and Countermeasure
It has been assumed for some years that the ACHOO syndrome is inherited. If a parent has the ACHOO syndrome, the children will inherit it with 50% probability.
The most likely explanation is that in ACHOO syndrome "patients" the optic nerve and, among other things, the nasal mucosa regulating triplets are too close to each other. If the optic nerve is irritated by the influence of light, the trilling nerve also responds and triggers a photic sneeze reflex. Even the rapid change of light and dark leads to a photic sneeze reflex.
However, most people with ACHOO syndrome do not sneeze more than three times (but few people have to sneeze up to 40 times), and after the eyes become accustomed to brightness (usually after 20 seconds), sneezing subsides. Even sunglasses can only help with a weak shape. There is no other treatment.
Often, a relationship between the ACHOO syndrome and a nasal sheath curvature is observed. Otherwise, it is believed that the ACHOO syndrome is safe - that's why science has invested no tremendous effort in the study of the photic sneeze reflex. Caution should be exercised only when driving, for example when driving out of a long tunnel.