Cause of persistent cough
A persistent cough may be caused by: a long-term respiratory tract infection, such as chronic bronchitis asthma – this also usually causes other symptoms, such as wheezing, chest tightness and shortness of breath an allergy smoking – a smoker's cough can also be a symptom of COPD bronchiectasis – where the airways of the lungs become abnormally widened postnasal drip – mucus dripping down the throat from the back of the nose, caused by a condition such as rhinitis or sinusitis gastro-oesophageal reflux disease (GORD) – where the throat becomes irritated by leaking stomach acid a prescribed medicine, such as an angiotensin-converting enzyme inhibitor (ACE inhibitor), which is used to treat high blood pressure and cardiovascular disease In most cases, a doctor won't worry whether a cough is dry or chesty, but will need to know if you are producing much more or darker phlegm than usual. Rarely, a persistent cough can be a symptom of a more serious condition, such as lung cancer, heart failure, a pulmonary embolism (blood clot on the lung) or tuberculosis.