Coughing is a sudden noisy expulsion of air from the lungs. This is body’s natural reflex to expel any foreign matter that is accumulated in the airways. Most people with a cold or flu develop a cough. It can be dry and itchy, or chesty and phlegmy.
Cough may be classified by duration of the cough. Acute cough lasts for less than three weeks and is commonly due to an acute respiratory infection.
Coughing that has lasted for more than 3 weeks, but less than eight weeks, is classed as sub-acute, while a cough that has been present for more than eight weeks is known as a chronic cough.