Unravelling chronic cough: Causes, diagnosis and treatment

Chronic cough, defined as a cough lasting more than eight weeks in adults and more than four weeks in children, is a common and often debilitating condition. It can significantly impact a person’s quality of life, leading to physical discomfort, social embarrassment, and sleep disturbances. This article explores the underlying causes, diagnostic methods, and treatment options for chronic cough.

Causes of chronic cough

Chronic cough can be triggered by various factors, often making diagnosis challenging. The most common causes include:

• Upper airway cough syndrome (UACS): Previously known as postnasal drip syndrome, UACS is caused by mucus dripping down the back of the throat, often due to allergies or sinusitis.

• Asthma: Cough-variant asthma is a type where the predominant symptom is a dry cough. This can be triggered by exercise, cold air, or allergens.

• Gastroesophageal reflux disease (GERD): In GERD, stomach acid flows back into the oesophagus, irritating the throat and causing a chronic cough.

• Chronic bronchitis: A type of chronic obstructive pulmonary disease (COPD), chronic bronchitis is characterised by a persistent cough and mucus production for at least three months in two consecutive years.

• Medications: Certain medications, particularly angiotensin-converting enzyme (ACE) inhibitors used for hypertension, can cause chronic cough as a side effect.

• Infections: Post-infectious cough can linger after a respiratory infection, such as pneumonia or pertussis (whooping cough).

• Less common causes: Conditions such as bronchiectasis, interstitial lung disease, and lung cancer can also present with chronic cough.

Diagnosis

Diagnosing chronic cough involves a comprehensive approach, starting with a detailed patient history and physical examination. Key steps include:

Medical history: Understanding the patient’s symptoms, lifestyle, and any underlying health conditions is crucial. Questions about the duration, nature (dry or productive), and triggers of the cough help narrow down potential causes.

Physical examination: A thorough examination of the respiratory system, including listening to the lungs and checking for signs of postnasal drip or GERD, provides important clues.

Diagnostic tests:

• Chest X-ray or CT scan: These imaging tests can reveal lung abnormalities, infections, or tumours.
• Spirometry: This test measures lung function and can help diagnose asthma or COPD.

Allergy tests: Identifying specific allergens can pinpoint allergic causes of chronic cough.

pH monitoring: For suspected GERD, oesophageal pH monitoring assesses acid reflux.

Specialist referrals: In complex cases, referral to a pulmonologist, allergist, or gastroenterologist may be necessary for further evaluation.

Treatment

The treatment of chronic cough depends on addressing the underlying cause:

1. UACS: Managing allergies or sinusitis with antihistamines, nasal corticosteroids, or decongestants can reduce postnasal drip.
2. Asthma: Inhaled corticosteroids and bronchodilators are commonly used to control asthma symptoms.
3. GERD: Lifestyle changes (e.g., diet modification, weight loss), proton pump inhibitors, and H2 blockers are effective in reducing acid reflux.
4. Chronic bronchitis: Smoking cessation is crucial, along with bronchodilators and corticosteroids to manage symptoms.
5. Medication adjustment: If an ACE inhibitor is causing the cough, switching to a different class of antihypertensive medication can help.
6. Infections: Antibiotics or antiviral medications may be prescribed for bacterial or viral infections, respectively.
7. Other conditions: Treatment varies based on the specific condition, such as using immunosuppressants for interstitial lung disease or appropriate oncological treatments for lung cancer.

Lifestyle and home remedies

In addition to medical treatments, certain lifestyle changes and home remedies can help manage chronic cough:

• Hydration: Drinking plenty of fluids helps thin mucus and soothe the throat.
• Humidifiers: Using a humidifier adds moisture to the air, which can relieve dry cough.
• Avoiding irritants: Reducing exposure to smoke, pollutants, and allergens can decrease cough frequency.
• Honey and warm liquids: Consuming honey or warm teas can provide temporary relief for throat irritation.