2. WHAT IS A COUGH?
A cough is an abrupt, forceful ejection of air from the lungs. A cough is not only the single most frequent symptom for which patients seek medical care in the United States and around the world, but also one of the most perplexing and frustrating disease-provoking diagnostic challenges for the clinician. The purpose of a cough is to clear the airways and to protect them from inhaled foreign particles, such as pollen, dust, microbes, and others.
There are two types of coughs: dry cough (unproductive) and wet cough (productive). A productive cough often brings phlegm/sputum/mucus. The phlegm can be white, tan, yellow, green, or accompanied by streaks of blood. In some cases, a severe cough can result in straining of the rib muscles and cartilage, causing chest pain when breathing or moving. A cough can be bothersome, disrupting daily activities and interfering with sleep.