Persistent cough: Could it be something more serious?

A cough is a common symptom that often clears up within a few weeks, especially after a cold or chest infection. However, when a cough lasts longer than eight weeks, it is considered persistent or chronic. While most persistent coughs have a non-serious cause, in some cases, they can be a sign of an underlying health condition that requires medical attention.

What causes of a persistent cough are the most common?

Several common conditions can lead to a long-lasting cough. These include:

• Postnasal drip (also known as upper airway cough syndrome): Mucus from the nose drips down the throat, causing irritation.
• Asthma: Often linked with wheezing and shortness of breath, but in some cases, a cough may be the only symptom.
• Gastro-oesophageal reflux disease (GORD): Acid from the stomach irritates the throat, leading to coughing.
• Medication side effects: Particularly from ACE inhibitors used for high blood pressure.
• Smoking: Chronic cough is a well-known effect of smoking and exposure to other irritants like air pollution.

When should someone be concerned about a persistent cough?

If a cough continues for more than eight weeks, it is important to see a doctor. Certain features may raise concern and suggest a more serious underlying problem:

• Coughing up blood (haemoptysis)
• Unexplained weight loss
• Night sweats
• Persistent hoarseness
• Chest pain
• Shortness of breath that is worsening
• A history of smoking

These symptoms may indicate a condition such as lung cancer, chronic obstructive pulmonary disease (COPD), tuberculosis or another chronic lung disorder.

What tests might be needed to investigate a chronic cough?

The exact investigations will depend on the patient’s symptoms and history. In most cases, the GP or specialist may start with:

• Chest X-ray to check for infections, tumours or other abnormalities
• Spirometry to assess lung function and check for asthma or COPD
• Blood tests to identify infection or inflammation
• Referral to ENT if postnasal drip or sinus problems are suspected
• Referral to a gastroenterologist if acid reflux is a possible cause

Further imaging such as a CT scan, or bronchoscopy (a camera to examine the airways), may be needed if initial tests are inconclusive.

What are some less common but serious causes of chronic cough?

Although rare, a chronic cough can sometimes be linked to more serious conditions. These include:

• Lung cancer
• Tuberculosis
• Interstitial lung disease
• Heart failure (causing fluid buildup in the lungs)
• Pulmonary fibrosis

How can a chronic cough be treated effectively?

Treatment for chronic cough depends entirely on the underlying cause. Options may include:

• Nasal sprays or antihistamines for postnasal drip
• Inhalers for asthma
• Proton pump inhibitors for reflux
• Stopping or changing medications if a side effect is suspected
• Smoking cessation support where applicable
• Specialist referral for further assessment

Can a persistent cough be prevented?

While not all causes are preventable, the risk of chronic cough can be reduced by:

• Not smoking
• Treating allergies or reflux early
• Avoiding exposure to pollutants or irritants

Managing chronic conditions like asthma effectively