Cough

A cough is a reflex action that occurs when the body needs to clear the airways of irritants, secretions, foreign particles, or microbes. Medically, coughing is a vital defensive mechanism that protects the respiratory system by expelling unwanted substances that could potentially impede breathing or cause infection. It can be classified as either acute or chronic, depending on its duration, with acute coughs typically lasting less than three weeks, and chronic coughs persisting longer, often due to underlying conditions such as asthma, gastroesophageal reflux disease (GERD), or chronic bronchitis.

The cough reflex is triggered by stimulation of sensory nerves in the lining of the respiratory tract, which then sends signals to the cough center in the brainstem. This center coordinates the complex series of actions involving the diaphragm, chest and abdominal muscles, and the glottis, resulting in a forceful expulsion of air from the lungs. While coughs can be productive, bringing up sputum (phlegm), or unproductive (dry), it is essential to assess the character, timing, and associated symptoms of a cough to determine its cause and appropriate treatment.