A cough happens when something irritates your throat or airways and your body reflexively pushes air out to clear it. Many different things can trigger this reflex, from mild, short-term issues to serious diseases.
How coughing works
Coughing is a reflex that starts when receptors in your airways sense irritation or excess mucus. These receptors send signals to your brain, which then tells the muscles in your chest and abdomen to forcefully expel air to try to remove the irritant.
Common short-term causes
Short-term (acute) coughs, lasting less than about 3 weeks, are most often caused by infections or temporary irritation. Typical causes include:
- Viral infections like the common cold or flu that inflame the nose, throat, and airways.
- Breathing in irritants such as smoke, dust, chemicals, strong fumes, or very cold air.
Causes of long-lasting cough
A cough that goes on for weeks or months usually has an underlying condition that keeps irritating the airways. Common longer-term causes include:
- Asthma, COPD, or chronic bronchitis, which inflame and narrow the breathing tubes.
- Postnasal drip, where mucus from the nose and sinuses runs down the back of the throat, and acid reflux (GERD), where stomach acid irritates the throat.
When cough is more serious
Sometimes a cough is a warning sign of a more serious problem and needs medical attention. Red flags include:
- Coughing up blood, unexplained weight loss, chest pain, trouble breathing, or a cough that lasts longer than 8 weeks in adults (4 weeks in children).
- Risk factors like heavy smoking or known heart or lung disease, where persistent cough can signal conditions such as heart failure, pneumonia, or even lung cancer.
If you describe how long you have been coughing and any other symptoms (fever, mucus, wheezing, heartburn, etc.), more specific possible causes can be outlined.
