Chronic Cough

How long is a chronic cough?

A cough after a viral infection often lingers for weeks because the airways stay sensitive. If it is steadily improving, it can usually be watched.

Common causes of chronic cough

Post-nasal drip (upper airway cough syndrome)

Mucus from the nose and sinuses drips down the throat, causing throat clearing, a tickle and cough, often worse lying down. Causes include allergic rhinitis, non-allergic rhinitis and chronic sinusitis. See post-nasal drip.

Asthma and cough-variant asthma

Cough may be the only symptom of asthma, typically dry, worse at night, with exercise, cold air or allergens. Wheezing and breathlessness may or may not be present. A related condition, non-asthmatic eosinophilic bronchitis, causes cough with airway inflammation but normal lung function tests and responds to inhaled steroids.

Acid reflux

Reflux can trigger cough through irritation of the throat or a reflex from the esophagus. Heartburn may be absent. Cough often worsens after meals, when lying down or on talking. See GERD.

ACE inhibitor medicines

Blood pressure medicines ending in "-pril" (lisinopril, ramipril, enalapril) cause a dry, tickly cough in up to about 1 in 10 people. It can start days to months after the first dose and usually resolves within 1 to 4 weeks of stopping, occasionally longer. Switching to another medicine is the fix.

Smoking and COPD

Smoker's cough is a daily, often productive cough, worse in the morning. Chronic bronchitis and COPD cause cough, phlegm and breathlessness. Stopping smoking reduces cough within weeks to months.

Less common but important causes

• Bronchiectasis: widened, scarred airways causing daily cough with large amounts of phlegm and repeated chest infections.
• Whooping cough: coughing fits lasting weeks to months ("the 100-day cough"), sometimes with a whoop or vomiting.
• Tuberculosis: cough with fever, night sweats and weight loss, especially after travel or contact with TB.
• Lung cancer: a new or changed cough in a current or former smoker, blood in phlegm, hoarseness or weight loss.
• Interstitial lung disease: dry cough with progressive breathlessness and crackles in the lungs.
• Heart failure: cough with breathlessness and swelling.
• Inhaled foreign body: especially in toddlers, often after a choking episode.
• Obstructive sleep apnea, vocal cord dysfunction and habit cough in some people.

Refractory or unexplained chronic cough

When no cause is found, or the cough persists despite treating all likely causes, it is called refractory chronic cough. The cough reflex itself is oversensitive: triggers like talking, cold air, perfume or laughter set off coughing, often with a tickle in the throat. This is known as cough hypersensitivity syndrome and is more common in middle-aged women.

Chronic cough in children

In children, a cough lasting more than 4 weeks needs assessment. Common causes differ from adults: protracted bacterial bronchitis (a wet cough that responds to antibiotics), post-viral cough, asthma, whooping cough, an inhaled object and, less often, cystic fibrosis or immune problems. A wet cough lasting more than 4 weeks warrants a doctor's review.

Diagnosis

1. History: smoking, medicines, timing, triggers, phlegm, heartburn, nasal symptoms, travel and exposures.
2. Examination of the nose, throat, chest and heart.
3. Chest X-ray: recommended for all adults with chronic cough.
4. Spirometry with bronchodilator to look for asthma or COPD; a challenge test or exhaled nitric oxide (FeNO) and blood eosinophils can help detect airway inflammation.
5. Targeted trials of treatment, for example a nasal steroid or inhaled steroid for several weeks.
6. Further tests if needed: CT scan of the chest, sputum tests for TB or bacteria, sinus imaging, reflux testing, bronchoscopy or a referral to a cough clinic.

Treatment

• Post-nasal drip: saline rinses, steroid nasal sprays, antihistamines for allergies.
• Asthma and eosinophilic bronchitis: inhaled corticosteroids, with other asthma medicines as needed.
• Reflux: weight loss if needed, avoiding late meals, raising the head of the bed, and acid-reducing medicines when there are reflux symptoms.
• ACE inhibitor cough: switching to another blood pressure medicine.
• Smoking: stopping smoking with support and medicines.
• Bronchiectasis and COPD: airway clearance, inhalers, pulmonary rehabilitation, antibiotics for infections.
• Refractory chronic cough: speech and language therapy (cough control techniques), and low-dose nerve-modulating medicines such as gabapentin, pregabalin or low-dose morphine under specialist guidance. Newer medicines that target cough nerves are approved in some countries.

Over-the-counter cough syrups have little proven benefit for chronic cough. Honey can soothe a cough in adults and children over 1 year; never give honey to babies under 12 months.

Living with chronic cough

A persistent cough can cause exhaustion, poor sleep, chest wall pain, urine leakage, vomiting, hoarseness and social embarrassment. Sipping water, sucking lozenges, breathing through the nose and swallowing when you feel a tickle can help interrupt the urge.

Frequently asked questions

What is considered a chronic cough?

In adults, a chronic cough is one that lasts 8 weeks or longer. In children, a cough lasting more than 4 weeks is considered chronic. Coughs lasting 3 to 8 weeks are usually lingering effects of a respiratory infection.

What are the most common causes of a cough that won't go away?

In nonsmokers, the most common causes are post-nasal drip, asthma, acid reflux and ACE inhibitor blood pressure medicines. In smokers, chronic bronchitis and COPD are common. Many people have more than one cause, so several may need treating.

When should I worry about a chronic cough?

See a doctor promptly if you cough up blood, lose weight without trying, have night sweats, fever, breathlessness, chest pain or hoarseness for more than 3 weeks, or if you smoke and your cough changes. These can signal infection, tuberculosis or lung cancer.

Can acid reflux cause a chronic cough without heartburn?

Yes. Reflux can cause a chronic cough even without heartburn, sometimes called silent reflux. The cough may be worse after meals, when lying down or when talking. Lifestyle changes help, and acid-reducing medicines are tried when reflux symptoms are present.

How is chronic cough treated if no cause is found?

When a cough persists despite treating likely causes, doctors call it refractory chronic cough. Speech and language therapy teaches cough control techniques, and low-dose nerve-calming medicines such as gabapentin or pregabalin can reduce coughing. A specialist cough clinic can help.