Investigation of a long-lasting cough (Investigation of chronic cough)
The appointments and tests used to find out why a cough has lasted eight weeks or more, and to rule out serious causes.
✓ Medically reviewed by a GMC-registered consultant · last reviewed September 2026 · next review September 2027 · how we review
In short
- A cough lasting eight weeks or more should be checked, usually with a history, examination and a chest X-ray.
- Common causes include asthma, acid reflux, post-nasal drip, some blood-pressure medicines and lingering effects of a virus — but a cause is not always found.
- Tests and treatment trials can take several weeks, and more than one cause may be present at once.
- Coughing up blood, weight loss, or a cough with breathlessness or chest pain needs prompt medical assessment.
A plain-English summary. The detail — including risks and recovery — is below.
At a glance
A general guide. Your specialist will give you advice for your situation.
Checks for and rules out serious causes of a long-lasting cough.
A cough with red-flag features (coughing up blood, weight loss, marked breathlessness) needs urgent assessment rather than a slow work-up.
You talk through your symptoms and are examined. Breathing tests may be done on the day and are usually not painful, though spirometry takes effort.
A clear explanation of the likely cause and the plan in plain language.
You talk through your symptoms and are examined. Breathing tests may be done on the day and are usually not...
Simple results, such as spirometry, may be available quickly. A chest X-ray is usually reported within days.
If a treatment trial is started, you take it as directed and note any change in your cough before your review.
Your response to treatment is assessed and the plan adjusted; further tests or referral may be arranged if the...
What does investigating a long-lasting cough involve?
A cough that lasts eight weeks or more is called a chronic cough. It is common and very often not due to anything sinister, but because it can occasionally be the first sign of a serious problem, it should be checked properly rather than ignored.
Investigating a chronic cough usually starts with a detailed conversation about your symptoms, your medical history, whether you smoke or have smoked, and your medicines. A physical examination follows, and a chest X-ray is commonly arranged. Depending on what is found, you may have breathing tests (spirometry), a test for airway inflammation (FeNO), blood tests, or a referral to an ear, nose and throat or other specialist.
Many long-lasting coughs are caused by asthma, acid reflux, mucus dripping from the nose and sinuses, a side effect of certain blood-pressure medicines, or a cough that lingers after a virus. Sometimes a treatment trial is used both to help and to confirm the cause. Importantly, a cause is not always found, and in some people the cough reflex simply becomes oversensitive.
The aim is to find and treat the cause where possible, rule out anything serious, and explain what to expect — not to promise the cough will disappear straight away.
Types, options & approaches
There may be different ways to do this. The right approach depends on the clinical question and your circumstances.
Options at a glance
These are the main approaches described in this guide. The right option depends on the diagnosis, your goals and what your clinician thinks is safe.
History and examination
A detailed discussion of your cough, triggers, other symptoms, smoking history and medicines, followed by listening to your chest and checking your nose, throat and general...
Chest X-ray
A common first test to look for problems in the lungs. A normal X-ray is reassuring but does not rule out every cause, so further tests may still be needed.
Breathing tests (spirometry and FeNO)
Spirometry measures how well your lungs work; a FeNO test measures inflammation linked to asthma. These help diagnose airway causes of cough.
Treatment trial
A timed trial of treatment, such as for reflux, rhinitis or asthma, used both to relieve symptoms and to confirm the likely cause when the diagnosis is uncertain.
Preparing for your test
- Make a note of when the cough started, what makes it better or worse, and any other symptoms such as heartburn, wheeze or a blocked nose.
- Bring a full list of your medicines, including any blood-pressure tablets, as some can cause a cough.
- Tell the clinician if you smoke or used to smoke, and roughly how much and for how long.
- Mention any coughing up of blood, weight loss, fevers, night sweats or breathlessness, as these need prompt attention.
- Bring details of any previous chest X-rays, asthma diagnoses or hospital letters.
- For breathing tests, ask whether you should avoid your inhalers or smoking beforehand, as this can affect results.
- Write down your questions, including what each test will and will not tell you.
What happens
At the first appointment the clinician asks about your cough in detail and examines you, listening to your chest and checking your nose and throat. They will review your medicines and smoking history.
A chest X-ray is often arranged, and you may be sent for breathing tests such as spirometry and a FeNO test, or have blood tests. These are quick and usually not painful, though spirometry involves blowing hard into a machine several times.
Depending on the most likely cause, you may be offered a treatment trial — for example for reflux, an allergic or runny nose, or asthma — and reviewed after a set time to see whether the cough improves. If the cause is still unclear, or if there are warning signs, you may be referred to a respiratory or ear, nose and throat specialist or have further imaging such as a CT scan.
Is this test right for me?
A good consultation should explore whether it's the right choice for you now — including reasons to wait or consider something else.
May not be suitable if…
- A cough with red-flag features (coughing up blood, weight loss, marked breathlessness) needs urgent assessment rather than a slow work-up.
- Breathing tests may not be possible if you are too unwell or unable to perform them on the day.
- A treatment trial is the wrong first step if a serious cause has not been excluded.
- Routine antibiotics are not an appropriate treatment for most chronic coughs.
Delay or rearrange if…
- You have an active chest infection that should settle before tests are interpreted.
- You are using inhalers or have recently smoked before breathing tests, which can affect results.
- You are or might be pregnant, which affects whether some imaging is done.
- Important previous results or letters are missing and need gathering first.
Alternatives to discuss
- Watchful waiting for a short period if the cough is mild and recent and there are no warning signs.
- Stopping or switching a medicine that may be causing the cough, on advice.
- Lifestyle measures such as stopping smoking and managing reflux triggers.
- Referral to a different specialty, such as ear, nose and throat, if that is the likely source.
Before you decide
Use this as a shared-decision checklist. The aim is not just “can this be done?”, but whether it is right for you, now, with the risks and alternatives clearly understood.
What matters most to me?
Think about symptoms, daily life, work, caring responsibilities, sport, fertility, travel, appearance and anxiety — the right choice depends on your priorities, not just the medical facts.
What are all my options?
Ask about waiting, monitoring, medicines, rehabilitation, a smaller or larger procedure, a different test, NHS referral, or a second opinion where that would help.
What would make me pause?
Active infection, pregnancy, unstable medical problems, smoking, medicines that increase bleeding, poor support at home, or feeling pressured are all reasons to slow down and get tailored advice.
What happens if I do nothing today?
For some problems, waiting is safe; for others, delay can make treatment harder. A good consultation should explain the trade-off in plain English.
Benefits
- Checks for and rules out serious causes of a long-lasting cough.
- Identifies common, treatable causes such as asthma, reflux or post-nasal drip.
- Reviews whether a medicine could be causing the cough.
- Guides a treatment plan tailored to the likely cause.
- Gives reassurance and a clear explanation when no serious cause is found.
- Helps you understand what to expect and when to seek further help.
Risks & complications
- A cause is not always found, even after testing
- Several weeks may pass before a treatment trial shows whether it helps
- Light-headedness or coughing during breathing tests
- Bruising where blood is taken
- Treatment trials that cause side effects without curing the cough
- Incidental findings on a chest X-ray or scan that need further tests
- Need for referral and further appointments
- A serious underlying cause found that needs urgent treatment
- A reaction to medicines used in a treatment trial
The main frustration is that more than one cause can be present, and finding the answer can take time and several treatment trials. A normal chest X-ray is reassuring but does not exclude every cause. Tell your clinician straight away if you cough up blood, lose weight without trying, or become breathless, as these change the urgency.
Published figures to discuss
There are no meaningful complication rates for this kind of assessment, because most of it is talking, examination and simple tests. The main uncertainty is diagnostic: a cause is not always found, more than one cause can coexist, and a normal chest X-ray does not exclude every condition, so results are interpreted alongside your symptoms over time.
| Figure | Reported range | How to interpret it | Source / confidence |
|---|---|---|---|
| Finding a single cause | Variable; more than one cause can coexist | Reflux, asthma/eosinophilic bronchitis, rhinitis/post-nasal drip, ACE inhibitors and smoking can overlap. | Guide sourcesClinical context |
| Normal chest X-ray but ongoing cough | Recognised | A normal film is reassuring but does not explain every cough. Persistent, changing or red-flag symptoms may still need further assessment. | North Bristol NHS Trust — Chronic coughnbt.nhs.ukSource-linked context |
| Medication-related cough | Common practical issue with ACE inhibitors | A medication review is part of good cough assessment; stopping or switching should be clinician-led. | Guide sourcesClinical context |
| Cancer or serious-disease red flags | Clinically important | Coughing blood, unexplained weight loss, persistent chest pain, breathlessness, hoarseness or recurrent pneumonia should not be treated as simple chronic cough. | North Bristol NHS Trust — Chronic coughnbt.nhs.ukSource-linked context |
These are literature figures, not a personalised prediction. Your own risks and likely benefits depend on your circumstances, your health, and how your care is carried out and followed up.
What happens afterwards
There is usually no physical recovery from these appointments and tests. "Afterwards" mainly means following any treatment trial, attending follow-up and waiting to see whether the cough improves.
- No immediate change in the cough while a cause is being found
- Mild light-headedness straight after blowing hard for spirometry
- A small bruise where blood was taken
- Gradual rather than instant improvement once treatment starts
Aftercare
- Take any treatment trial exactly as directed and for the full time advised before judging whether it works.
- Keep a simple diary of your cough and any triggers to help at your review.
- Avoid smoking and second-hand smoke, which irritate the airways and prolong a cough.
- Attend follow-up appointments, as the diagnosis may depend on your response to treatment.
- Report any new warning signs, such as coughing up blood or weight loss, promptly.
- Ask before stopping any regular medicine, even if you think it may be causing the cough.
- Note of when the cough started and its triggers
- Full list of medicines, including blood-pressure tablets
- Details of smoking history
- Any previous chest X-rays or asthma records
- Questions written down for the appointment
- A plan for who to contact if symptoms worsen
⚠ Get urgent help if…
- Coughing up blood, even a small amount
- Losing weight without trying
- Becoming breathless or wheezy, especially at rest
- Chest pain or pain on breathing
- A high temperature, night sweats or feeling very unwell
- Difficulty swallowing or a hoarse voice that does not settle
- Sudden severe breathlessness — call 999
Who to contact: your clinician, clinic or test provider first (keep their number to hand). For urgent advice when you can't reach them, call NHS 111. In an emergency, call 999.
General guidance — it doesn't replace the specific advice your specialist gives you.
Results & realistic expectations
A good outcome is finding a clear, treatable cause — such as asthma, reflux or post-nasal drip — and seeing the cough improve with the right treatment, or being reassured that nothing serious is going on. Some results, like spirometry, are available quickly; others depend on how you respond to a treatment trial over several weeks.
Tests cannot always pin down a single cause, and a normal result does not guarantee the cough will stop. In some people the cough reflex stays oversensitive and needs longer-term management rather than a one-off fix.
A cough caused by a clear, treatable problem often settles once that is managed, though it may take time. Where the cough reflex has become oversensitive, or where there is an ongoing condition such as asthma, the plan may need review and adjustment over months. Tell your clinician if the cough returns or changes.
Related tests, treatments or support
Investigating a cough often goes hand in hand with looking into related symptoms such as breathlessness, heartburn or a blocked nose, because these frequently overlap. Treating more than one contributing cause at the same time can be more effective than tackling one alone.
Follow-up & long-term care
You are usually reviewed after a chest X-ray or a treatment trial to check the result and your response. If the cough persists, has warning signs, or the cause is unclear, you may be referred to a respiratory or ear, nose and throat specialist or have further imaging. You should know who to contact if your symptoms change.
- Ongoing treatment for an identified condition such as asthma or reflux
- Avoiding smoking and known triggers
- Review if the cough returns, worsens or changes character
Repeat, follow-on and what comes next
- More than one treatment trial may be needed before the cause is clear.
- The plan is often adjusted at review depending on how you respond.
- Some coughs need ongoing management rather than a single fix.
- Referral or further imaging may follow if the cough persists or red flags appear.
Ask what happens if the result is unclear or needs repeating, and what is included if further tests or follow-up are needed.
What good aftercare looks like
- A clear explanation of the likely cause and the plan in plain language.
- A defined treatment trial with a set review date.
- Written warning signs and a contact route if symptoms worsen.
- A plan for referral or further tests if the cough does not settle.
What affects the cost
Costs vary a great deal between people and providers, and we don't publish prices. What matters is understanding what drives the cost and making sure your quote is complete. The main things that affect it:
- Length and number of consultations needed
- Which tests are arranged (chest X-ray, spirometry, FeNO, blood tests)
- Whether a CT scan or specialist referral is needed
- Reporting fees for scans and tests
- Follow-up appointments to review treatment trials
- Any treatments prescribed during the work-up
- The consultation fee and what it includes
- Which tests are included and which are charged separately
- Reporting fees for X-rays or scans
- Follow-up or review appointment costs
- What happens, and what it costs, if a referral or further imaging is needed
- How and when you will receive your results
On the NHS? A long-lasting cough is commonly investigated on the NHS, starting with your GP; private access may be used for a faster appointment or specialist opinion, but the assessment and tests are the same.
You're entitled to your total cost in writing — including reports, follow-up and what happens if the result is inconclusive — before you decide.
Consent traps and marketing red flags
These are not small details. They are often where patients lose choice, time to reflect, or realistic expectations.
Consent traps
- Reassurance based on a normal chest X-ray alone, without explaining its limits.
- Starting a treatment trial without explaining how long to wait before judging it.
- Not reviewing whether a medicine could be the cause.
- Not setting out clear warning signs that should prompt earlier review.
Marketing red flags
- Promising a quick cure for a long-lasting cough.
- Offering antibiotics as a routine fix without assessing the cause.
- Selling extensive scans before a basic assessment has been done.
- Claiming a single test can explain every cough.
Choosing a specialist safely
- Check the specialist is on the GMC Specialist Register for this area.
- Make sure they work at a CQC-registered service, and look for membership of the relevant Royal College or professional body.
- You're entitled to time to consider and to have your questions answered before you agree — the specialist who looks after you should explain it, not a salesperson.
- Be wary of pressure: time-limited offers or deposits taken before you've had time to think are red flags, not bargains.
- You're entitled to your total cost in writing — including any follow-up — before you decide.
Questions to ask your medical professional
Take this to your consultation. A good specialist will welcome every one of these.
- What do you think is the most likely cause of my cough?
- Which tests do I need, and what will each one tell you?
- Could any of my medicines be causing this cough?
- If we try a treatment, how long before we know if it is working?
- What happens if the tests are normal but the cough continues?
- What symptoms should make me come back sooner?
- Are you on the GMC Specialist Register for this area, and which Royal College or professional body are you a member of?
- Will you be the specialist who carries out my test, and who looks after me afterwards?
- What are the risks for someone like me, and how often do your own patients have a problem or need it repeated or redone?
- What does a realistic result look like — and what can this test not achieve?
- What are my options, including waiting, doing nothing for now, or choosing a different approach?
- Can I have written information, results and aftercare instructions in a format I can use, including any accessibility or communication support I need?
- What is the total cost in writing, including any follow-ups, and how much time do I have to decide?
Frequently asked questions
When does a cough count as chronic?
What are the usual causes?
Will I definitely find out the cause?
Can I get this investigated on the NHS?
Why might my medicine be causing the cough?
When should I worry about a cough?
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How we made this page
Medically reviewed by a GMC-registered consultant. Written in plain English, checked against NHS, NICE, GMC and relevant Royal College / specialist-society guidance, and kept under review. No clinic paid to appear on this page, and we publish no pricing. This is general information to help you prepare — it is not a substitute for advice from your own clinician. How we review our guides →
Source hierarchy: UK regulator and NHS/NICE guidance first, then relevant Royal College or specialist-society guidance, then peer-reviewed evidence for procedure-specific figures where available.
Sources & standards: North Bristol NHS Trust — Chronic cough NHS — Cough NICE NG12 — Suspected cancer: recognition and referral (lung) Cancer Research UK — Supporting earlier diagnosis of lung cancer
Reviews reflect patients' experience of care, not clinical outcomes. For procedure volumes and outcome data see PHIN.
Last medically reviewed 2026-09-21. Spotted something wrong or out of date? Report an error in this guide.
Related guides: Respiratory consultation · Chest X-ray · Spirometry (lung function test) · FeNO test (exhaled nitric oxide) · Investigation of breathlessness