Clinical Definition

Postnasal drip is the secretion of mucus into the nasal pharynx from the posterior nasal cavities. The condition is often chronic, with excessive or thick secretions. Allergies, sinusitis and upper respiratory tract infections may cause the condition. Postnasal drip is a common cause of sore throat and coughing.

In Our Own Words

Postnasal drip is the accumulation or trickling of mucus from the sinuses behind the nose downward along the back of the throat. Normally, mucus in your throat is continually produced, and you swallow it unconsciously. In some instances, however, the mucus can become thick or be produced in excess.

When this occurs, you may feel the mucus dripping down the back of your throat. Common causes of this symptomatic postnasal drip include allergies, sinus infections and the common cold. Chronic postnasal drip may cause a sore throat and coughing, especially at night. In addition to your symptoms, doctors can sometimes see things when looking at your throat that suggest postnasal drip.