Persistent Cough: Separating Myth From Guidance
Persistent Cough: what people commonly get wrong, set against what published US guidance says.
A cough that does not go away is a common symptom of lung cancer, and finding it early makes a large difference.
Key takeaways
- Chest cold (acute bronchitis): cough usually improves within 3 weeks
- Cough after a viral infection: can linger for several weeks
- Most useful single change: See your doctor if a cough lasts more than 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.
What the guidance actually says
The published position, before we get to what people believe instead.
| Measure | Figure |
|---|---|
| Chest cold (acute bronchitis) | cough usually improves within 3 weeks |
| Cough after a viral infection | can linger for several weeks |
| See your doctor | for a cough lasting more than 3 weeks |
| Common medicine cause | ACE inhibitors, which can cause a dry cough |
| Always needs assessment | coughing up blood, in any amount |
Where people go wrong
What people tend to think, set against what is actually published.
- Waiting months to see whether it settles
- Assuming a smoker's cough is normal
- Asking for antibiotics for a viral cough, which they do not help
What to do instead
- See your doctor if a cough lasts more than three weeks
- Mention any smoking history and any weight loss
- Note whether it is worse at night or with exercise, which can point to asthma
- Ask whether a blood pressure medicine could be responsible
The part that is genuinely uncertain
Guidance changes, and it changes because evidence does. The figures above reflect current US guidance from the bodies named at the foot of this page; where those bodies revise their position, theirs is the account to follow rather than this one.
Related topics
- Common Childhood Infections: What the Evidence Actually Says (Children's Health)
- What the Guidance Really Says About Acid Reflux (Digestive Health)
- RSV (Respiratory Syncytial Virus): Sorting the Evidence From the Noise (Infectious Diseases)
- Choking: What the Evidence Actually Says (Emergency Care)
Where to go next
- Understanding Persistent Cough: A Plain-English Explainer
- Persistent Cough: A Practical Checklist
- Persistent Cough — the reference entry
- Respiratory Health: The Complete Guide
- Smoking and the Lungs: Sorting the Evidence From the Noise
- Air Quality: What the Evidence Actually Says
When to speak to a doctor
See your doctor for a cough lasting more than three weeks, or sooner for coughing up blood, unexplained weight loss, night sweats, chest pain, hoarseness that does not go away, or increasing breathlessness. Call 911 for severe difficulty breathing, blue or gray lips, or a child who is struggling to breathe, grunting or limp.
Where this comes from
- CDC — Chest Cold (Acute Bronchitis)
- American Cancer Society — Lung Cancer Signs and Symptoms
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, summarized or generalized 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 your doctor, 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 911.
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