Post-nasal drip (PND) occurs when excessive mucus
is produced by the sinuses. The excess mucus
accumulates in the throat
or back of the nose.Post-nasal drip can be caused by excessive or thick secretions, or impairment in the normal clearance of mucus from the nose and throat.
Various causes for chronic post nasal drip are allergies,viral infections,deviated nasal septum,chronic sinusitis,adenoid enlargement and diseases like sarcoidosis and GERD.