Does the light make you sneeze? Relax, there are more people like you

It happens almost every week: I leave the doorway of my house and, just as my face crosses the border where the shadow of the goal gives way to the direct sunlight, a tingling appears that starts near the eyes and progresses to the nose to end up becoming one or more sneezes.

It has happened to me for as long as I can remember, usually when I have been in the shade for a long time and suddenly I am exposed to bright sunlight. It took me many years to find out that this phenomenon is nothing like "allergy to the Sun" that he thought he had, that is called bright light sneeze reflex, either photic sneeze, and that it is fixed in the DNA of many people: from 18% to 35% of the population experiences it.

The false allergy to the Sun

The idea that strange stimuli produce the uncontrollable urge to sneeze is usually directly associated with types of allergies. Perhaps because of this, some people believe that their propensity to sneeze right after coming into direct contact with a strong light source is due to some kind of strange allergy, something that does not serve to explain why they need to sneeze at the moment of being illuminated and not during the entire time they remain under that source of light.

Other people don't even stop to think about whether sneezing because of light is something strange or not; they take it for granted that it happens to everyone, and when they first notice that others are taken aback by their sneezing in the light, they wonder if they are being pranked.

Both possibilities are very reasonable, since the propensity for photic sneezing is a sufficiently rare characteristic to be considered rare but, at the same time, it does not cause so many problems as to be considered something similar to a disease. The bright light sneeze reflex may be annoying on the rare occasions that it is expressed, but it is not a form of allergy to sunlight.

What is a photic sneeze?

The photic sneeze reflex is a genetically inherited trait. which is expressed in the appearance of the impulse (automatic and involuntary) to sneeze when the area of ​​the face is suddenly exposed to a source of intense light.

It is necessary to keep in mind that what produces these sneezes is not so much the intense light itself as the contrast that is experiments between the shady area where you have been before and the area exposed to direct light where you are after. That is why this false "allergy to the Sun" is only expressed during the first seconds or minutes after having passed to a well-lit place.

Causes of photic sneezing

The phenomenon of the photic sneeze reflex is relatively common, since it could affect a third of the population, but despite that, more research is still needed on the subject to find out what triggers these sneezing.

Of course, possible causes of the photic sneeze reflex are being considered. The most widely accepted is one that has to do with the trigeminal nerve, one of the brain nerves that leave directly from the brain without passing through the spinal cord that runs through the spine.

This set of neurons It fulfills the function both of informing the brain of things that happen in other parts of the body and of a channel through which the brain transmits orders to other organs. Specific, one of the jobs of the trigeminal nerve is to detect signs of irritation in the nose to start the necessary paperwork to start sneezing right after.

In people who have inherited the photic sneeze reflex, the trigeminal nerve may be closer than normal to the trigeminal nerve. ocular nerve of each half of the face, so that it "intercepts" information from it and confuses it with data coming from the nose. In this way, when there is a sudden exposure to intense light, the trigeminal nerve would be taking this wave of sensory data as an indication that something is wrong in the nose; hence the sneezing.

Is it dangerous to have this reflex?

Currently, the only context in which photic sneezing is considered to be potentially dangerous is in combat aircraft piloting..

The rest of us can limit ourselves to providing extra caution when driving, for example by wearing sunglasses, and celebrating the small eccentricities of our body.