Understanding the problem

Coughs can be classified according to their duration: 

• Acute coughs usually last less than three weeks and have a sudden onset. They can be caused by an upper respiratory tract infection such as a cold, flu, covid-19 or sinusitis; an infection of an area further down the airways (as is the case in pneumonia and bronchitis); inhalation of dust, smoke or another foreign substance; an allergy such as hay fever, or a flare-up of a long-term respiratory condition like asthma or chronic obstructive pulmonary disease (COPD).
• Subacute coughs usually last around three to eight weeks. Infections are the most common cause, particularly whooping cough (pertussis) in children.
• Chronic coughs last for eight weeks or longer in adults or four weeks in children. They usually have a more gradual onset, and the cause can be more difficult to pinpoint. Possible causes include a long-term allergy (e.g. to house dust mites); an undiagnosed respiratory condition such as chronic bronchitis or asthma; smoking, or certain medications – particularly ACE inhibitors (e.g. ramipril). Postnasal drip – mucus dripping from the nose into the throat because of a condition such as sinusitis – is another possible cause, as is irritation of the throat from stomach acid due to gastro-oesophageal reflux disease (GORD). Persistent coughs can also be a sign of something more serious (e.g. lung cancer, tuberculosis, pulmonary embolism or heart failure), although this is rare.

Coughs can also be referred to as chesty or dry. A chesty (productive) cough will often make the sufferer feel as if they are trying to bring something up – usually described as mucus or phlegm. A dry (tickly or non-productive) cough often starts as a tickle at the back of the throat, but there is no production of mucus or phlegm.