What causes cough?

A cough is a protective reflex that moves mucus, dust, smoke, or another irritant out of the throat and airways. A cold can inflame the upper airways, while asthma can narrow and sensitise the breathing tubes. Bronchitis, COPD, bronchiectasis, and bronchiolitis can also increase mucus or airway inflammation. A dry cough may follow a viral infection or irritation; a wet cough brings up phlegm. The sound alone cannot identify the cause.

Cough can also be triggered by post-nasal mucus, allergies, acid reflux, vaping, smoking, or some medicines. A cough that persists, changes, or repeatedly returns deserves assessment, even when it began with a cold.

Rest, drink fluids, and avoid smoke, vaping, dust, and strong scents. Warm drinks may soothe an irritated throat. Follow the label of any pharmacy medicine and check with a pharmacist if you take regular medicines, are pregnant, or are treating a child. Do not start antibiotics just because mucus is coloured; they help only selected bacterial infections. A clinician may listen to your chest and choose treatment such as an inhaler or nebuliser treatment when the airway is narrowed.

Seek urgent help for severe difficulty breathing, blue or grey lips, confusion, fainting, chest pain, or coughing up blood. Arrange prompt medical review if the cough is worsening, keeps returning, disrupts sleep, comes with fever or breathlessness, or lasts longer than expected after an infection. Children who are struggling to breathe, unusually sleepy, or unable to drink need urgent assessment.

Ask what pattern your cough suggests, whether you need a chest examination or breathing tests, and which triggers to avoid. Mention when it started, whether it is dry or brings up phlegm, smoking or vaping exposure, reflux symptoms, allergies, and every medicine you use.