What is a cough? Well, the medical world describes a cough as an explosive expiration that provides a protective mechanism for clearing the tracheobronchial tree of secretions and foreign material.(1) Did you know that a cough is one of the most common symptoms for which patients seek medical help? Reasons include discomfort from the cough itself, interference with normal lifestyle, and fear of the connection with cough to some underlying illness.

Coughing may be initiated either voluntarily or as a reflex. Cough receptors are located in the pharynx, stomach, external auditory canal, diaphragm, nose, and the large airways of the tracheobronchial tree. These receptors react to a stimulus and then initiate the cough reflex.(2) Coughs can be brought on by inhaling things that irritate the airways such as smoke, dust, or fumes; or by breathing in such things as contents of the stomach, upper airway secretions, or foreign bodies. When the irritations are due to upper airway secretions, as is seen in postnasal drip, or gastric contents, as in gastroesophageal reflux disease (GERD), the actual cause may go unrecognized and the cough may be persistent. Prolonged exposure to irritants often causes airway inflammation, which itself can trigger cough, and make the airway more sensitive to other irritants.

Any disorder that causes inflammation, irritation, constriction, or compression of airways can lead to coughing. Airway inflammation commonly results from bacterial or viral infection. In viral bronchitis, airway inflammation sometimes persists long after the acute symptoms are gone, thereby producing a prolonged cough lasting for several weeks. The duration of a cough is a vital clue to its cause. The most common causes of chronic cough are postnasal drip, bronchial asthma, GERD, chronic bronchitis, and bronchiectasis.(3)

The smoking of cigarettes, pipes, and cigars irritates the airways and reduces the efficiency of the ciliated cells that move particle-laden mucus upwards and outwards causing a characteristic hacking "smoker's cough." There are many other factors that would be associated with coughing and your healthcare professional is the best person to help you determine the cause. Some of the more serious causes include congestive heart failure, and lung diseases.