Medically speaking, sneezing is also known as sternutation. It's the response of the mucous membrane of the nose to an irritant or foreign body that causes allergy in a hypersensitive person. 3 Possible causes of sneezing : Common Cold, Nasal Allergies and Rhinitis.

Causes and Symptoms:

Sneezing can occur from a number of causes, or may itself be a symptom of an underlying condition, most likely an allergy or common cold. Sneezing may simply be triggered by a small foreign object or substance in the nose, including particles of pepper, smoke, irritating chemical fumes, or gases. It may also be a symptom of a common cold, upper respiratory tract infection, hay fever, or other allergies to pollen, dust, dust mites, mold, dander, grass, or other substances. Additional potential causes of sneezing include withdrawal from opiate drugs, inhaling corticosteroids, whooping cough, or anaphylaxis. Many people sneeze when they step outdoors into bright sunlight.

How a sneeze works :

A sneeze starts with irritation of the lining of the nose, and ends in an explosion of air from the nose and mouth. Nerve impulses travel from the nose to the brain, then back to other nerves that control the muscle of the abdomen, chest, diaphragm, neck, face and eyelids as well as the mucus glands and blood vessels of the nose. That’s why we usually end up closing our eyes when we sneeze, and why the nose often runs afterwards.

Sneezy Facts :

A sneeze travels at approx 180 km per hour. The world record for sneezing is held by Donna Griffiths from Worstershire in the UK, who sneezed for 978 days in a row, stopping on 16 September 1983 !