When individuals sneeze upon exposure to bright lights like the sun, they may be exhibiting symptoms of autosomal dominant compelling helio-ophthalmic outburst syndrome (ACHOO).
There are several reasons why intense light, such as sunlight, can induce sneezing. (Image credit: AndreyUG/Shutterstock) Have you ever found yourself suddenly wanting to sneeze upon stepping outside from a dimly lit building into the full brightness of the sun? You’re not alone—this reflex affects as many as one in three people. This phenomenon, known as the photic sneeze reflex, has intrigued scientists since at least the fourth century B.C., when Aristotle pondered why people are more prone to sneezing after gazing at the sun. According to the Cleveland Clinic, the photic sneeze reflex is also termed “autosomal dominant compelling helio-ophthalmic outburst syndrome” or ACHOO. This reflex is an autosomal dominant trait, meaning there is a 50% chance of inheriting it if one biological parent exhibits the trait, as explained by the National Center for Biotechnology Information. Sponsored Links
The way you clench your fist reveals important details about your personality.Kingdom Of Men Photic sneezing typically occurs following exposure to bright light, such as sunlight, especially during transitions from darkness to light, such as turning on lights in a dark room. “It’s not triggered by a specific light wavelength but by changes in light intensity,” said Dr. David Lang, chair of the Department of Allergy and Clinical Immunology at the Cleveland Clinic, speaking to Live Science. The severity of photic sneezing varies among individuals. For some, it may occur sporadically, while for others, exposure to bright light can provoke uncontrollable sneezing episodes, noted the Cleveland Clinic. Related: What happens when a baby takes its first breath? A study in 1995 found that 33% of approximately 370 patients surveyed at an eye clinic in Alabama experienced photic sneezing. A more recent study in China in 2019 revealed that about 25% of some 3,400 individuals examined displayed this reflex. Sign up now for the Live Science daily newsletter Get the world’s most intriguing discoveries delivered directly to your inbox. Contact me with news and offers from other Future brands I would like to receive email from our trusted partners or sponsors By submitting your information you agree to the Terms & Conditions and Privacy Policy and are aged 16 or over. Scientists continue to investigate the exact cause of photic sneezing. One hypothesis is that bright light might stimulate the trigeminal nerve, which extends throughout the face. According to Lang, light that activates the nerve branch leading to the eye may also stimulate the branch connected to the nose. RELATED MYSTERIES —Why do scents evoke powerful memories? —Why does water come out of your eye when you blow your nose forcefully? —Why does cold fresh air alleviate nausea? In a 2010 study, researchers at genetic testing company 23andMe identified two mutations associated with photic sneezing. Additionally, the 1995 Alabama study suggested a possible link between photic sneezing and a deviated nasal septum. Meanwhile, a 2019 study in Japan found a potential connection between this reflex and migraines. Photic sneezing is generally harmless, “although it could heighten the risk of an accident while driving or during activities like acrobatics or playing sports,” said Dr. William Howland, medical director of Orion Clinical Research in Austin, speaking to Live Science. “The primary way to manage photic sneezing is by wearing sunglasses outdoors. Antihistamines typically used for allergies do not affect this reflex.” Another method to potentially prevent photic sneezing is by applying pressure to the philtrum—the groove under the nose—horizontally with a finger. “It’s like giving yourself a mustache with your finger,” Lang explained. A 2019 Australian study suggested that this pressure might override nerve irritation caused by bright light or interfere with nerve signals that trigger photic sneezing.
