Autosomal Dominant Compelling Helioopthalmic Outburst Syndrome is characterized by uncontrollable sneezing in response to the sudden exposure to bright light, typically intense sunlight.
This type of sneezing is also known as photic sneezing, also known as photoptarmosis – a condition of uncontrollable sneezing in response to numerous stimuli. About one in four individuals who already have a prickling sensation in their nose will sneeze in response to sunlight, but pure photic sneezing is far less common.
Sneezing is usually triggered by contact with infectious agents or after inhaling irritants, but the cause of photic sneezing is not fully understood. It may involve an over-excitability of the visual cortex in response to light, leading to a stronger activation of the secondary somatosensory areas.
“I like to write when I feel spiteful. It is like having a good sneeze.”
– D. H. Lawrence
Sneezing usually feels good because, much like an orgasm, sneezes are reflexes involving tension and release. Also, like climaxes, they sometimes feel like they are about to happen, but do not; and like the final throes of sex, they can erupt as loud crescendos or pop off like a string of firecrackers.
Some evidence suggests that sneezing, like orgasms, also releases endorphins. Unlike orgasms though, sneezes can travel at about 100 miles per hour.
Ross: I was in the shower, and I felt something.
Chandler: Was it like a sneeze, only better?
– Friends (1996) Season 3, Ep. 23; “The One with Ross’s Thing” [No. 71]
Curiously, in English, it is common to say “Bless you”; in German, “Gesundheit”; in Hindu, one person says “Live” and the other responds “With you”; and in Zulu people say “I am now blessed”. The ancient Greeks and Romans said “Banish the Omen”.