Persistent coughs

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
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