9 causes of cough you should know

Although a cough is part of the body's natural defence mechanism to expel irritants gaining entry into the respiratory system and aggravating the respiratory linings, prolonged or severe coughing can be a symptom of a deeper problem. To treat a severe cough it is important to identify the underlying cause of the cough.

'Maximum patients visiting a doctor complain about dry cough caused due to congestion of respiratory mucosa (or blocking of the respiratory tract due to excessive mucus production),' says Dr Pradip Shah, consultant physician, Fortis Hospital, Mahim. There could be several other causes of a cough however, which can be determined by the type of cough and symptoms associated with it. We highlight some common and rare causes of a cough with inputs from Dr Shah.

1. Viral infection: 'It is the most common cause of a dry cough, precipitated due to direct airborne transmission of the virus, intake of cold drinks or ice-cream or due to allergic reaction to oily food', says Dr Shah.
2. Gastroesophagus reflux disease (GERD): 'People often feel a burning in the chest or throat called heartburn. Sometimes, they taste stomach fluid in the back of the mouth. If anyone suffers from these symptoms more than twice a week, they may have GERD. Some people can also have GERD without having heartburn. Your symptoms could include a dry cough, asthma symptoms, or trouble swallowing. Such individuals commonly complain about a cough early in the morning or at night. It happens because of the loosening or lack of coordination between contraction and relaxation of the (sphincter) muscle that prevents the reflux of food. This causes stomach acid to flow back to the food pipe and cause irritation of the lining, thus triggering a cough,' says Dr Shah.
3. Allergies: Environmental pollution, smoke from industries and chemical pollutants can trigger a cough due to allergic congestion in the respiratory tract. This type of cough usually subsides when you go away from the allergen.^[2]
   
4. Chronic bronchitis: It is an ongoing, serious condition. It occurs if the lining of the bronchial tubes is constantly irritated and inflamed, causing a long-term cough with mucus. Smoking is the main cause of chronic bronchitis.
   
5. Asthma: A cough can also be caused due to allergic bronchial asthma. Patients usually suffer from recurring bouts of coughing that cause breathlessness and wheezing. These recurring bouts of cough are triggered as a reflex mechanism to expel the allergen out of the body.^[2]
   
6. Whooping cough: A typical whooping or hoarse sound while coughing in children indicates whooping cough, caused by bacteria. It is not very common nowadays because of effective vaccination.^[3]
7. Tuberculosis: Prolonged productive cough coupled with extreme fatigue and weight loss typically indicates a bacterial infection of lungs. 'If the patient coughs up blood along with mucus then tuberculosis is suspected,'says Dr Shah.
8. Pneumonia: Pneumonia symptoms are initially similar to those of acute bronchitis. It initially causes a dry cough and later develops into a productive cough with thick greenish mucus, sometimes with blood stains.^[1]
9. Lung cancer:'Lung cancer is the most common cause of coughing in heavy smokers and tobacco users. Usually, a cough lasting for more than three weeks, which gradually starts worsening with presence of blood, breathlessness, unexplained weight loss, extreme fatigue and chest pain may be indicative of lung cancer,'says Dr Shah.

References:

1. Cough. A.D.A.M. Medical Encyclopedia
2. Asthma. A.D.A.M. Medical Encyclopedia
3. Pertussis. Whooping cough. A.D.A.M. Medical Encyclopedia

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