Understanding Persistent Cough: A Plain-English Explainer
Persistent Cough: what it is, why it matters, and what published guidance actually asks of you.
It is the commonest presenting symptom of lung cancer, and stage at diagnosis dominates outcome.
Key takeaways
- Typical viral cough: settles within 3 weeks
- Post-viral cough: can persist 6-8 weeks
- Most useful single change: See a GP if a cough passes three weeks.
- Commonest mistake: Waiting months to see whether it settles.
- See a doctor if any of the signs under "When to speak to a doctor" below apply to you.
The short answer
A cough lasting longer than the three weeks a typical viral illness accounts for.
Where it fits
This is part of Respiratory Health. Below: the numbers first, then what to do with them.
The numbers, in one place
| Measure | Figure |
|---|---|
| Typical viral cough | settles within 3 weeks |
| Post-viral cough | can persist 6-8 weeks |
| Threshold to see a GP | more than 3 weeks |
| Common medicine cause | ACE inhibitors, causing a dry cough |
| Always needs assessment | coughing up blood, in any amount |
What that means in practice
What that looks like in practice:
- See a GP if a cough passes three weeks
- Mention smoking history and any weight loss
- Note whether it is worse at night or with exercise, suggesting asthma
- Ask whether an ACE inhibitor could be responsible
What gets people into trouble
The pitfalls worth knowing about:
- Waiting months to see whether it settles
- Assuming a smoker's cough is normal
- Requesting antibiotics for a viral cough
Where to go next
- Persistent Cough: A Practical Checklist
- Persistent Cough: Separating Myth From Guidance
- Persistent Cough — the reference entry
- Smoking and the Lungs: Sorting the Evidence From the Noise
- Air Quality: What the Evidence Actually Says
When to speak to a doctor
See a GP for a cough lasting more than three weeks, or sooner for coughing up blood, unexplained weight loss, night sweats, chest pain, hoarseness lasting three weeks, or increasing breathlessness. Call 999 for severe difficulty breathing, blue lips, or a child who is struggling to breathe, grunting or floppy.
Where this comes from
How this page was put together
Every figure, recommendation and warning above is taken from the guidance named in Where this comes from. Nothing on this page is inferred, summarised or generalised beyond what those bodies publish: where they give a number, it is their number, and where they are silent, so are we. Pages are rebuilt whenever the underlying record changes. Sign-off by a named clinician, where it has happened, is shown at the top of the page along with the date.
Medical disclaimer
This article is general information, not medical advice. It cannot account for your own history, medication or circumstances. Always speak to a GP, pharmacist or another qualified health professional before making changes that affect your treatment, and never delay seeking medical advice because of something you have read here. In an emergency, call 999.
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