Cough is commonly caused by minor infection and is short-lived. Persistent cough needs investigation and can be caused by a number of conditions including lung disease and others.
Coughing caused by an infection usually resolves in a few weeks. Occasionally it is much more prolonged.
Cough lasting more than eight weeks is “chronic cough” and further evaluation to consider the cause is appropriate. Many forms of lung disease can cause chronic cough but serious causes are uncommon. Cough can also result from heart conditions, drug treatments, post-nasal drip, reflux disease, and other conditions.
A persistent cough can be driven by complex neural mechanisms. known as “cough hypersensitivity syndrome”. Persistent coughing and throat clearing can traumatise the delicate throat tissues and perpetuate the situation.
Specialist respiratory evaluation of persistent cough is appropriate because management is dependent on identifying the cause. The history and physical examination are important and further tests might involve breathing tests, chest-x-ray, CT scan, cardiac tests, and others depending on the individual situation.