Persistent Cough: Common Causes
and When to See a Doctor

A cough is a reflex that clears mucus, irritants and germs from the airways. It becomes persistent when it carries on well beyond the usual course of a cold or chest infection. UK health services generally advise having a cough lasting more than 3 weeks checked.

Doctors describe a cough as dry or productive. A dry cough brings up nothing, while a productive cough brings up phlegm. The type offers clues but cannot confirm the cause by itself.

Viral infections are the most common reason for a cough that hangs on, because the airways can stay irritated for weeks after a cold or flu. Asthma, hay fever, mucus dripping from the nose into the throat and acid reflux are other frequent causes.

Some causes are more serious, including COPD (chronic obstructive pulmonary disease), pneumonia, tuberculosis, whooping cough and, less often, lung cancer. A group of blood pressure medicines called ACE inhibitors can also cause a dry cough.

A risk factor is not a cause. Smoking, dust or fumes at work, and a history of asthma or allergies make a long-lasting cough more likely.

Call 999 if a cough comes with severe difficulty breathing, blue or grey lips, chest pain that does not ease, or collapse. Get same-day medical advice if a cough comes with:

• Blood in your phlegm, or coughing up blood.
• New or worsening breathlessness or wheezing.
• Unexplained weight loss or drenching night sweats.
• A high temperature that lasts or keeps returning.
• A hoarse voice lasting several weeks.
• A new lump in the neck.

Not everyone needs every test. A clinician decides based on your history and examination:

• Questions about how long the cough has lasted, triggers, smoking history and medicines.
• An examination, including listening to your lungs and checking oxygen levels.
• A chest X-ray to look for infection, fluid or changes in the lungs.
• Blood tests for signs of infection, inflammation or anaemia.
• Breathing tests such as spirometry to check for asthma or COPD.
• A phlegm sample if infection is suspected.
• A CT scan or other specialist tests if the X-ray does not explain the cough.

Treatment depends on the cause, how long symptoms have lasted and your other conditions:

• Cough after a virus: usually settles with time, rest and fluids. Antibiotics do not treat viruses.
• Bacterial chest infection: antibiotics may be prescribed after assessment.
• Asthma or COPD: inhalers and other regular medicines, plus a check of your technique.
• Hay fever or nasal drip: antihistamines or nasal sprays.
• Acid reflux: changes to meals and acid-reducing medicines.
• ACE inhibitor cough: your prescriber may suggest an alternative. Do not stop the medicine without advice.
• Smoking: support to stop is often central to care.
• Serious causes: referral to a specialist team for further tests and treatment.

Drink plenty of fluids, and try a warm drink with honey and lemon if you are over one year old. Avoid smoke and other irritants, and prop yourself up with extra pillows if the cough is worse at night. Evidence for cough medicines is limited, so ask a pharmacist before buying one. Self-care suits a short cough, not one that is lingering or alarming.

Arrange a routine appointment for a cough that has lasted three weeks or longer, even if you feel well. Seek same-day advice from a GP, NHS 111 or an urgent care service if you have any warning sign above. A cough that is worsening, or has changed in sound or pattern, should be checked sooner. Call 999 for severe breathing difficulty or collapse. Tell your clinician about every medicine you take.

• Check registration with the Care Quality Commission (CQC).
• Ask whether a chest X-ray, blood tests and CT are available through the same provider.
• If you are looking for a respiratory specialist Milton Keynes providers list, or a private respiratory consultant, check their entry on the General Medical Council's specialist register.
• Ask for fees in advance, including tests and follow-up.
• Ask how results are shared and who arranges the next step.

Bloom Health is a CQC-registered private hospital in Milton Keynes. Its walk-in urgent care centre lists chest infections among the problems it treats, from 8am to 10pm daily. The walk-in GP runs from 2pm to 10pm daily for ongoing concerns. No appointment or referral is needed, the visit fee is £95, and tests are billed separately.

On-site diagnostics include X-ray and CT, with a radiographer available from 12pm to 8pm daily, and blood tests covering infection and inflammatory markers. The GP service lists referrals into specialist care when further assessment is needed. A clinician reviews results and explains the next steps.

Understanding the usual persistent cough causes makes it easier to decide when waiting is reasonable and when to get checked. Many long coughs follow an infection, asthma or reflux, but blood in phlegm, breathlessness or weight loss need prompt attention. If your cough is dragging on, a clinician can listen to your chest, arrange useful tests and explain the next step.