Why do we sneeze?
We sneeze to clear irritants such as dust, pollen or germs from the nose. Nerves in the nasal lining send a signal to the brain, which triggers a powerful burst of air.
A sneeze is a reflex that starts when something irritates the inside of the nose. The brain coordinates the muscles of the chest, throat and face to take a deep breath and then force air out through the nose and mouth at high speed, carrying the irritant away.
Allergies, colds, the flu, dust, smoke, strong smells and even plucking eyebrows can trigger sneezing. Sneezes can spray tiny droplets several meters, which is why covering your mouth and nose with a tissue or your elbow helps stop germs from spreading.
Bright light sneezes
About one in five people sneeze when they suddenly see bright light, such as sunlight. This photic sneeze reflex runs in families. Scientists think signals from the eyes and nose may cross over in the brain.
Did You Know?
It is very difficult to keep your eyes open while sneezing, because the reflex closes the eyelids automatically. The old story that your eyes could pop out is a myth.
This answer is general information, not medical advice. For a personal health question, talk to a doctor.