When should you see a doctor about a persistent cough?

Coughing can follow a viral infection and may also be related to asthma, allergies, reflux, smoking, medicines or irritation. A persistent cough is a presentation of lung cancer in some people, and it can occur with mesothelioma, non-small-cell lung cancer or small-cell lung cancer. These conditions share symptoms with many non-cancerous problems, so a cough cannot determine the diagnosis by itself. Duration, sound, triggers and associated symptoms help guide testing.

Record when the cough began, whether it is dry or brings up mucus, and whether it changes with exercise, lying down, meals or time of day. Note breathlessness, wheezing, chest discomfort, fever, night sweats, hoarseness and any blood. Bring a medicine list and mention smoking, workplace dust or fibre exposure, recent infections and previous lung conditions. A clinician may listen to your chest and arrange imaging or breathing tests.

Get urgent help for significant breathing difficulty, blue lips, severe chest pain, confusion, fainting, or more than a small streak of blood when coughing. Arrange prompt review for a cough that steadily worsens, returns after treatment, causes repeated vomiting, disturbs sleep or occurs with persistent hoarseness or unexplained weight change. Anyone with a current or previous cancer diagnosis should tell their oncology team about a new or changing cough.

Ask what causes are being considered, whether a chest examination, scan or breathing test is needed, and how to manage the cough safely. Ask which symptoms should prompt urgent care and when follow-up should happen if it continues.