When one can not drain over production of mucous from sinusitis through nasal opening due to swelling and blockage of sinus, postnasal drip occurs.
Post nasal drip is a sensation of mucous build up in the throat. The cause is over-production of mucous by glands in the nose and in the throat.
The mucous serves a healthy purpose at certain level, cleaning and moistening nasal passages, trapping foreign matter that has been inhaled, moistening and humidifying the air breathe, and even fighting infection.
At an unhealthy level, the body will react to the infection by sending its defense system of white blood cells to the nasal passages to trigger more mucous production in order to "wash out" the bacteria, irritants, or foreign matter.
But this tends to further congest and infect the nose, other sinuses, ear cavity, tonsils, pharynx, larynx.
Studies show post nasal drip as a cause of bad tastes and even bad breath, when bacteria settles in it, extracts sulfur compounds from amino acids in proteins and produces bad smell.
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