Photic sneeze reflex

Photic sneeze reflex is a genetic autosomal dominant trait, which causes sneezing when exposed suddenly to bright light, possibly many times consecutively. It is also referred to as photic sneeze response, sun sneezing, photogenic sneezing, the photosternutatory reflex, being photo sensitive, ACHOO syndrome, and "Achooism," with its related backronym Autosomal dominant Compelling Helio-Ophthalmic Outburst syndrome. The condition affects 17 to 35 percent of humans.Fact|date=October 2008

The first mention of the phenomenon is probably in the later work attributed to Aristotle (Problems, book XXXIII).

Mechanism

The probable cause is a congenital malfunction in nerve signals in the trigeminal nerve nuclei. The fifth cranial nerve, called the trigeminal nerve, is apparently responsible for sneezes. Research suggests that some people have an association between this nerve and the nerve that transmits visual impulses to the brain. Overstimulation of the optic nerve triggers the trigeminal nerve, and this causes the photic sneeze reflex.

Another theory suggested that tears leaking into the nose through the nasolacrimal duct are a cause of the photic sneeze reflex, but this has been proven wrong. The speed of the reflex seems to favor the first theory, as it happens much too quickly for tears to be generated and drain into the nose. In addition this sneeze reflex can be brought on by a sudden inhaling of cold air or a strong flavor such as a strong mint gum. This implies an overstimulation of any nerve close to the trigeminal nerve can cause the sneeze reflex.

Management

While this phenomenon is poorly understood, recent research has shown that antihistamines being used to treat rhinitis due to seasonal allergies may also reduce the occurrence of solar sneezes in people affected by both conditions. [cite journal |year=1987 |month=May |title=Solar Sneeze Reflex |journal=Western Journal of Medicine |volume=146(5) |pages=20 |url=http://www.pubmedcentral.nih.gov/pagerender.fcgi?artid=1307391&pageindex=1 |accessdate= 2007-12-18 ]

References

* Beckman L, Nordenson I. "Individual differences with respect to the sneezing reflex: an inherited physiological trait in man?" "Hum Hered." 1983, 33(6):390-1, PMID 6674114.
* Benbow EW: Practical hazards of photic sneezing. Brit. J. Ophthal. 75: 447, 1991.
* Breitenbach RA, "The photic sneeze reflex as a risk factor to combat pilots." "Mil Med." Dec 1993, 158:806-9, PMID 8108024.
* Collie WR, Pagon RA, Hall JG, Shokeir MH. "ACHOO syndrome (autosomal dominant compelling helio-ophthalmic outburst syndrome)." "Birth Defects Orig Artic Ser." 1978, 14(6B):361-3, PMID 728575.
* Deshmukh N. "Sneezing response to bright light. Is it a cause of accidents?" "The Guthrie Journal." 1995, 64(3):104-5.
* Everett HC. "Sneezing in response to light." "Neurology." 1964, 14:483-90, PMID 14144120.
* Forrester JM. "Sneezing on exposure to bright light as an inherited response." "Hum Hered." 1985, 35:113-4, PMID 3988295.
* Morris HH 3rd. "ACHOO syndrome: prevalence and inheritance." "Clev Clin J Med." 1987, 54:431-3, PMID 3665024.
* Peroutka SJ, Peroutka LA. "Autosomal dominant transmission of the 'photic sneeze reflex.'" "N Engl J Med." Mar 1 1984, 310(9):599-600, PMID 6694722.
* Semes LP, Amos JF, Waterbor JW. "The photic sneeze response: descriptive report of a clinic population." "J Am Optom Assoc." June 1995, 66(6):372-7, PMID 7673597.
* Whitman BW, Packer RJ. "The photic sneeze reflex: literature review and discussion." "Neurology." May 1993, 43(5):868-71, PMID 8492938.

External links

*OMIM|100820
* [http://www.madsci.org/posts/archives/aug97/865380242.Me.r.html MadSci article on the photic sneeze reflex]
* [http://loin.free.fr/john/medical_articles.html Annotated biography on medical journals on the photic sneeze reflex]
* [http://www.straightdope.com/classics/a2_303.html The Straight Dope on photic sneeze reflex]
* [http://www.experienceproject.com/group_profile.php?g=61993 Photic Sneezer Support]