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In the majority of cases, coughs are caused by
respiratory infections, including:
- colds or influenza, the most common causes of coughs
- bronchitis, an inflammation of the mucous membranes of the
bronchial tubes
- croup, a viral inflammation of the larynx, windpipe, and
bronchial passages that produces a bark-like cough in children
- whooping cough, a bacterial infection accompanied by the high-pitched
cough for which it is named
- pneumonia, a potentially serious bacterial infection that
produces discolored or bloody mucus
- tuberculosis, another serious bacterial infection that
produces bloody sputum
- fungal infections, such as aspergillosis, histoplasmosis, and
cryptococcoses.
Environmental pollutants, such as cigarette smoke,
dust, or smog, can also cause a cough. In the case of cigarette
smokers, the nicotine present in the smoke paralyzes the hairs (cilia)
that regularly flush mucus from the respiratory system. The mucus
then builds up, forcing the body to removed it by coughing.
Post-nasal drip, the irritating trickle of mucus from the nasal
passages into the throat caused by allergies or sinusitis, can also
result in a cough. Some chronic conditions, such as asthma, chronic
bronchitis, emphysema, and cystic fibrosis, are characterized in
part by a cough. A condition in which stomach acid backs up into the
esophagus (gastroesophageal reflux) can cause coughing, especially
when a person is lying down. A cough can also be a side-effect of
medications that are administered via an inhaler. It can also be a
side-effect of beta-blockers and ACE inhibitors, which are drugs
used for treating high blood pressure. |
