A persistent cough has a number of potential causes and should involve the care of specialists including internists
, allergists, pulmonologists
, ear-nose-throat specialists
, and others.
A cough that has been present for at least three weeks is classified as "subacute" and if it lasts for at least eight weeks it is "chronic." The cough reflex is complicated and involves various surfaces including the airways but also the esophagus, diaphragm, and even heart lining. The most common cause of a lingering cough is postnasal drip, asthma, and gastroesophageal reflux. Sometimes, certain medications can cause this. A post-infectious cause an especially common cause of a subacute cough, sometimes with the cough staying long even after the acute infectious symptoms are gone. Symptoms of postnasal drip also usually include frequent nasal discharge and a sensation of liquid dripping in the back of the throat with frequent throat-clearing. Asthma may be associated with episodic wheezing and shortness of breath. There are other medical conditions including chronic lung diseases can also cause a persistent cough.
It is not possible to make a diagnosis without seeing the patient. It is the strong recommendation to seek consultation with an internists and be evaluated in person.