Question: Why do we sneeze when we get cold?

Krishna Mohan Surapaneni answered on 17 Mar 2014:

Sneeze is nothing but the forcible/stormy release of air through the nose and mouth.

Sneezing is a neurological process that usually starts with physical stimulation of the wide-ranging trigeminal nerve.

This nerve’s branches are responsible for sensation in the face and surrounding skull areas.

The branches that terminate in the facial skin are sensitive to chemical, mechanical and tactile stimulation, including sensations of pain and temperature. Branches also serve the sensitive lining of the nasal passages.

While irritation of the nasal passages is the most common trigger for a sneeze, the presence of cold, dust-bearing air is not necessary. Simply being cold and shivering, or even moving from one temperature zone to another, can jar the nerve.

Eventually the impulses converge on the sneezing center in the brain’s lateral medulla, and when they reach a threshold, the nerves that control inhalation and explosive exhalation are recruited.