Cough (Persistent)
Symptoms, Causes & Treatment
A persistent cough — one lasting more than 3 weeks — always warrants medical review. It is one of the most common reasons for GP consultation in the UK. Most causes are benign and treatable, but persistent cough can occasionally indicate serious underlying disease.
What is a Persistent Cough?
A cough is described as persistent when it lasts more than 3 weeks. The three most common causes in non-smokers are asthma, ACE inhibitor medication, and gastro-oesophageal reflux. In smokers over 50, persistent cough requires urgent assessment to exclude lung cancer. Most persistent coughs respond well to targeted treatment once the underlying cause is identified.
Symptoms of Persistent Cough
A persistent cough is defined as lasting more than 3 weeks. Its character — dry, productive, nocturnal, triggered — gives important clues to the underlying cause.
Cough lasting more than 3 weeks · Dry or productive cough · Worse at night or after lying down · Triggered by cold air, exercise, or allergens · Associated throat clearing, post-nasal drip, or heartburn · May produce sputum, mucus, or phlegm · Associated wheeze or breathlessness
Coughing up blood (haemoptysis) · Night sweats and unexplained weight loss · Persistent hoarse voice lasting more than 3 weeks · Difficulty swallowing · Cough in a smoker over 50 · Swelling in the neck · Progressive breathlessness accompanying the cough
Cough with blood, unexplained weight loss, night sweats, persistent hoarse voice, or if you are a smoker over 50 — see a GP urgently, same-day if possible.
What Causes a Persistent Cough?
Persistent cough has many potential causes. The three most common are asthma, ACE inhibitor side effect, and GORD — together accounting for over 90% of cases.
Asthma is one of the most common causes of a persistent dry cough, particularly when it occurs at night, on waking, or is triggered by exercise and cold air. Cough-variant asthma may present with cough as the only symptom, without wheeze.
ACE inhibitors (e.g. ramipril, lisinopril, perindopril) cause a persistent dry cough in 10–15% of patients due to bradykinin accumulation in the airways. The cough stops within 1–4 weeks of switching to an ARB (e.g. losartan).
Acid reflux (GORD) causes microaspiration of gastric acid into the airways, triggering a chronic cough. The cough may be the only symptom, without typical heartburn. A trial of PPI therapy for 4–8 weeks can confirm the diagnosis.
Upper airway cough syndrome (formerly post-nasal drip) from rhinitis, sinusitis, or nasal polyps causes a persistent cough from mucus dripping onto the posterior pharynx. Treating the underlying nasal condition resolves the cough.
Viral respiratory infections are the most common cause of acute cough. Post-viral cough persists for 3–8 weeks after resolution of the acute illness due to airway inflammation and hypersensitivity. It is self-limiting but can be prolonged in susceptible individuals.
Lung cancer, tuberculosis, bronchiectasis, and interstitial lung disease all cause persistent cough. Any cough in a smoker over 50 lasting more than 3 weeks requires chest X-ray and clinical review to exclude serious pathology.
Key Risk Factors
Diagnosing a Persistent Cough
The cause of persistent cough is identified through careful history (duration, character, triggers, medications), physical examination, and targeted investigations.
Treatment for Persistent Cough
Treatment of persistent cough is directed at the underlying cause. Identifying the trigger is the most important step.
Supportive Measures
Stay well hydrated to thin mucus secretions. Avoid known triggers such as cold air, smoke, and strong smells. Honey and lemon may soothe throat irritation. Elevate the head of the bed if reflux is suspected. Avoid lying flat within 3 hours of eating.
Refractory & Recurrent Cough
Recurrent or persistent cough despite treatment should prompt reassessment. Specialist referral to respiratory medicine may be needed for refractory cough. Cough hypersensitivity syndrome and habit cough are increasingly recognised conditions requiring specialist speech and language or respiratory therapy.
When to Seek Help
Seek same-day or emergency care if you are coughing up frank blood, have severe breathlessness accompanying the cough, or have signs of serious systemic illness (fever, weight loss, night sweats with a new cough).
Any cough lasting more than 3 weeks should be assessed by a GP, particularly in smokers. New cough in a smoker over 50 should be seen within 2 weeks with a chest X-ray arranged.
Preventing Persistent Cough
Many persistent coughs can be prevented by addressing their underlying causes early.
Identify and remove the cause of chronic cough — change ACE inhibitor, treat GORD, control rhinitis. Removing the trigger resolves the cough in the majority of cases.
Avoid known triggers for cough: tobacco smoke, air pollutants, chemical fumes, cold air, and allergens. Use HEPA air filters at home if allergic triggers are identified.
Elevating the head of the bed and eating at least 3 hours before lying down reduces nocturnal acid reflux, one of the most common causes of persistent cough.
Keep the upper airways clear with nasal saline irrigation (neti pot), stay well-hydrated, and treat allergic rhinitis promptly to prevent upper airway cough syndrome from developing.
Stay up to date with vaccinations — flu, COVID-19, and pneumococcal — to reduce the frequency and severity of respiratory infections that cause post-viral cough.
A GP can identify the cause of persistent cough through history, examination, and investigations. Prompt review of any cough lasting more than 3 weeks — especially in smokers — is essential to exclude serious pathology.
Getting Treatment for a Persistent Cough
A GP can identify the cause of a persistent cough through history, examination, and investigations, and start targeted treatment. An online GP consultation with photos or a video call is an effective first step for assessing cough.
Expert clinical advice, when you need it.
Persistent Cough — Frequently Asked Questions
The most common causes are asthma, ACE inhibitor medication, gastro-oesophageal reflux (GORD), and upper airway cough syndrome from rhinitis or post-nasal drip. Less commonly, persistent cough can be caused by lung conditions including COPD, TB, or lung cancer. Any cough lasting more than 3 weeks should be assessed by a GP.
You should see a GP if a cough lasts more than 3 weeks, if you are coughing up blood, if you have unexplained weight loss or night sweats, if you are a smoker over 50, or if you have a persistent hoarse voice alongside the cough. These are all red flags requiring prompt assessment.
Yes. ACE inhibitors — including ramipril, lisinopril, and perindopril — cause a persistent dry tickly cough in up to 15% of people who take them. Switching to an ARB (such as losartan) resolves the cough within 1–4 weeks. Always discuss with your GP before stopping any medication.
Yes. Acid reflux from GORD causes microaspiration of acid into the airways, triggering a persistent cough that may occur without heartburn. A 4–8 week trial of a proton pump inhibitor (PPI) can both confirm and treat this cause.
Post-viral cough after a cold or respiratory infection typically lasts 3–8 weeks. It results from airway inflammation and increased cough reflex sensitivity. Steam inhalation, honey and lemon, staying hydrated, and avoiding irritants all help. See a GP if it persists beyond 8 weeks.
Yes. Cough-variant asthma presents as a persistent dry cough, particularly at night or early morning, without wheeze. It is diagnosed by spirometry or FeNO testing and responds to inhaled corticosteroid treatment.
Coughing up blood (haemoptysis) always requires same-day or urgent GP assessment. Small amounts of blood-streaked sputum can come from throat irritation, but blood in the sputum may indicate lung infection, pulmonary embolism, or — in smokers — lung cancer.
An online GP consultation with a description of the cough pattern, associated symptoms, and medication history is an effective first step. Your GP can arrange a chest X-ray, spirometry, or other tests and start treatment without delay.