Submitted by Venkat Gunnam on Mon, 03/04/2013 - 13:50

A very common symptom of a respiratory illness, cough is the 5th most important cause of visiting a health care provider.  According to a study conducted in Madhya Pradesh, the prevalence of cough of greater than 3 weeks duration was 2.8% in males and 1.2% in females. Cough can be normal physiological process or manifestation of a abnormal health condition. In this article we provide basic information on cough that we think every reader needs to be empowered with.


What is cough?


Coughing is a process by which your body tries to clear  secretions or foregin particles from your lungs. In conditions such as pneumonia there are increased secretions in the lungs and cough helps to clear these secretion. If food or liquids go the wrong pipe into the lungs they initiate a coughing spell that helps clear the lungs. It can be normal for people to cough occasionally to clear the lungs of the normal secretions.

How do you classify cough?

As cough can be a manifestation of wide variety of diseases, to help identify the cause of cough it is commonly classified  based on duration as acute (lasting less than 3 weeks) or chronic (lasting greater than 3 weeks).

What are the illnesses that cause cough?

As noted above cough can be caused by various health conditions. Here we list some common conditions that can cause significant cough:

Respiratory tract related (Lungs):

  • Upper Respiratory Infection (URI)
  • Post nasal drip
  • Pneumonia
  • Chronic Obstructive Pulmonary Disease
  • Asthma
  • Tuberculosis
  • Whooping cough
  • Lung tumor
  • Blood clot in lungs

Cardiac (heart) causes:

  • Congestive heart failure


  • ACE inhibitors (type of blood pressure medicine)


  • Gastro esophageal reflux disease
  • Smoking
  • Seasonal allergies

What is URI?

URI or upper respiratory tract infection is an acute infection affecting the nose, sinuses and throat. The onset is sudden and is accompanied by other symptoms of runny nose, sneezing, sore throat and generalized malaise and fatigue.

What is pneumonia?

An acute infection of the lungs, caused by bacteria, fungi or virus, pneumonia is characterized by inflammation of the lung tissue. Apart from cough, the patient also suffers from fever, usually high grade; cough is productive of sputum which is colored in case of bacterial infections, shortness of breath and chest pain.

What is post nasal drip?

Post nasal drip is the continuous flow of mucus from the nose to the back of the throat this is irritating and can cause symptoms of cough, sore throat and headache. This can be seen in people with allergies or with infections such as common cold.

What is chronic obstructive pulmonary disease?


Chronic obstructive pulmonary disease is a disease characterized by destruction of the walls of alveoli (sacs present in lungs). It usually occurs in individuals who have a history of heavy smoking. Cough is productive of mucus and is often associated with shortness of breath.


What is asthma?

Asthma is an allergic disorder which is characterized by spasms of the bronchi (the breathing tube) caused due to exposure to allergens (trigger factors) such as dust, mite, pollen etc. The symptom is usually increased after exposure to the causative allergen and is associated with wheezing sounds in the chest.

What is tuberculosis? How is it different from COPD?

Tuberculosis is an infection of the lungs caused by bacteria. There is often a history of exposure with associated symptoms of low grade fever, night sweats, loss of weight and decreased appetite. COPD is caused mainly due to smoking, whereas tuberculosis is a bacterial infection. In some people both the problems can coexist.

What are the symptoms of lung cancer?

Chronic cough (lasting more than 3 weeks) can some times be the only symptoms of lung cancer. Apart from cough, lung cancer can be associated with loss of appetite and weight, fever and night sweats. People with long history of smoking or who have long exposure to asbestos or other carcinogens are at higher risk for lung cancer.

What is Gastro esophageal reflux disease (GERD)?

In people with GERD  the stomach acid backs up into the throat and irritates the throat causing cough. It can also cause burning sensation in the chest, which is usally called as heart burn. This is one of the common causes of Chronic cough (Cough lasting more than 3 weeks).

What are the common tests that a doctor will order when a patient presents with a symptom of cough?

Though a thorough history taking and physical examination may suggest the probable diagnosis, still functional and imaging studies are necessary to confirm the diagnosis is some cases. Various diagnostic tests that may be ordered are:

  • Chest X-Ray to diagnose pneumonia
  • Chest CT to diagnose changes of COPD
  • PFTs to check the lung capacity
  • Pulse oximetry
  • Sputum cytology and culture in cases of tuberculosis
  • Bronchoscopy and biopsy to diagnose lung cancer

Can I get cough if some body next to me is coughing?

Some of the infectious causes of cough such as tuberculosis and viral infectious can be spread by cough. But as described above most of the causes of cough are non infectious and usually not spread from one person to the other by cough.

How is cough treated?

Treatment is directed towards the illness diagnosed and depends on each condition. If you have cough that is present for a long time or have other symptoms with cough consult your doctor to get appropriate treatment.