Photic sneeze reflex is a condition triggered by exposure to bright light. The next time you head outside on a sunny day, see if you let out a sneeze or series of sneezes. Your reaction might be due to allergies, or it might be the change in light. If you have the reflex, you probably inherited the trait from a parent.
Is photic sneeze rare?
Reflexive sneezing induced by light, and sunlight in particular, is estimated to occur in 18 to 35 percent of the population and is known as the photic sneeze reflex (PSR) or the ACHOO (autosomal dominant compulsive helio-ophthalmic outbursts of sneezing) syndrome.
Why do I sneeze when I look at the sun?
When a stimulus excites one part of the body's parasympathetic nervous system, other parts of the system tend to become activated as well. So when bright light causes the eye's pupils to constrict, that may indirectly cause secretion and congestion in the nasal mucus membranes, which then leads to a sneeze.
How common is photic sneezing?
An estimated 10 to 35 percent of the population has a photic sneeze reflex. “It's not a disease,” University of California, San Francisco neurologist and human geneticist Louis Ptáček told the NewsHour. “Some people find it annoying, but some people like it to some extent.