Chronic phlegm

Chronic phlegm means regularly coughing up mucus from the airways over a prolonged period — the classic definition of chronic bronchitis is a cough with phlegm on most days for at least three months, in two consecutive years. The airways normally make a small amount of mucus to trap dust and germs, but ongoing irritation or infection makes them produce much more. The commonest cause is smoking, which inflames the airways and is the basis of chronic bronchitis and COPD. Other causes include long-term asthma, bronchiectasis (permanently widened, mucus-prone airways), repeated or lingering chest infections, and post-nasal drip from the sinuses running down the throat. The colour and nature of the phlegm give clues: clear or white is usual with irritation, while yellow or green often accompanies infection, and — importantly — blood in the phlegm always needs assessment. A long-standing productive cough that changes character, or comes with breathlessness, weight loss or blood, should be looked into rather than dismissed as a 'smoker's cough'.

• Smoking-related chronic bronchitis / COPD — the commonest cause of a long-term productive cough.
• Asthma — especially when poorly controlled.
• Bronchiectasis — permanently widened airways that produce a lot of phlegm.
• Repeated or lingering chest infections.
• Post-nasal drip — mucus from the sinuses running down the throat.
• Blood in the phlegm — always needs assessment, as it can have serious causes.

Chronic phlegm is assessed mainly by history and examination, often with breathing tests (spirometry) and a chest X-ray. Blood tests support this: a full blood count and CRP for infection or inflammation, and alpha-1-antitrypsin in younger patients or non-smokers with airway disease to look for the inherited cause. If an infection is present, the phlegm itself can be sent for culture. Where a more serious cause is possible — for example a persistent change in a long-term cough, or blood in the phlegm — imaging such as a CT scan is arranged. Mediora.AI can surface an infection or inflammatory pattern, or a low alpha-1-antitrypsin, from your results, but a persistent productive cough is assessed by a doctor, usually with breathing tests and a chest X-ray.