Why does a person sneeze?

Sneezing is a sudden, involuntary expulsion of air from the lungs through the nose and mouth. It is a natural reflex that helps the body to expel foreign particles, such as dust, pollen, and other irritants, from the nasal passages.

The sneezing reflex is triggered when the nasal passages are irritated. This can be caused by a variety of factors, including:

* Allergies: Allergies are a common cause of sneezing. When a person is allergic to something, their immune system overreacts to the allergen, producing antibodies that bind to cells in the nose and throat. When the allergen is encountered again, these antibodies trigger the release of histamine and other chemicals, which cause inflammation and sneezing.

* Colds and flu: Colds and flu are viral infections that can cause inflammation and irritation of the nasal passages, leading to sneezing.

* Sinusitis: Sinusitis is an inflammation of the sinuses, which are located around the nose and eyes. Sinusitis can be caused by a variety of factors, including allergies, colds, and flu, and can cause sneezing.

* Other irritants: Other irritants that can cause sneezing include dust, pollen, smoke, and chemical fumes.

The sneezing reflex is a natural reflex that helps the body to protect itself from harmful substances. It is important to note, however, that sneezing can also spread germs, so it is important to cover your nose and mouth when you sneeze.