Health care professionals point out that coughing is a symptom and not a disease. A cough occurs when the airways to the lungs become irritated. It is the body's way of keeping the throat and airways clear. While most times a cough does not signal a serious problem, in some cases, prolonged coughing can be the symptom of an underlying disease. Even though a cough can be annoying, a productive cough that brings up mucus is the body's way of healing itself. A dry, hacking cough, or nonproductive cough, often occurs following exposure to irritants such as dust or smoke.
Doctors say that a cough is one of the most common reasons patients come in to see them. Causes include the common cold, upper respiratory tract infections like the flu, pneumonia or whooping cough, acute sinusitis and allergies, in which case postnasal drip can cause coughing. A cough that comes on suddenly and lasts for fewer than three weeks is characterised as an acute cough. Although a cough will usually go away on its own, people frequently take over-the-counter antihistamines and decongestants to treat a cough that is the symptom of a cold. Sometimes a doctor may prescribe an antibiotic as treatment for symptoms of acute sinusitis, which do not go away.
A cough that lasts longer than three weeks is considered to be a subacute cough. Sometimes a cough will persist for several weeks following a cold or other viral respiratory tract infection. Often the result of bronchitis or postnasal drip, a subacute cough will generally go away on its own without treatment. A combination decongestant-antihistamine medication may help to alleviate symptoms. In some cases, acute sinusitis may require a course of antibiotic treatment to get rid of a cough.
A lingering cough that continues for more than eight weeks is described as a chronic cough. Treatment is aimed at curing the underlying cause of the cough rather than temporarily relieving the symptom. Doctors say that in 25 per cent of the cases involving a chronic cough, the cough is caused by other medical conditions. Post-nasal drip from acute sinusitis is the most common cause. Other causes include asthma, GERD (gastro-oseophageal reflux disease), emphysema from smoking, chronic bronchitis and certain medications such as ACE inhibitors used to treat blood pressure. Beta blockers prescribed to treat migraines also can cause a chronic cough. Other less common but more serious causes of a chronic cough include pulmonary embolism, heart failure or lung cancer. Fluid accumulating in the lungs often is responsible for people with heart failure developing a cough. Symptoms of pulmonary embolism and lung cancer include shortness of breath and coughing up blood.