A cough is one of the body’s natural defense mechanisms. It helps clear mucus, irritants, and germs from the airways. Most coughs disappear within a few days or weeks. However, when a cough lasts more than 8 weeks in adults (or more than 4 weeks in children), it is called a chronic cough.
Chronic cough should never be ignored because it may indicate an underlying infection or lung disease.
What Is a Chronic Cough?
A chronic cough is a persistent cough that continues long after the initial illness should have resolved. Unlike a common cold cough, it often interferes with sleep, work, and daily activities.
It may be:
- Dry cough
- Wet (productive) cough
- Night-time cough
- Continuous throat irritation
Major Infections That Cause Chronic Cough
1. Tuberculosis (TB)
One of the most important causes worldwide, especially in developing countries.
Why it causes cough:
TB bacteria infect lung tissue and create inflammation and cavities, irritating airways.
Associated symptoms
- Cough lasting >2–3 weeks
- Blood in sputum
- Fever (often evening)
- Night sweats
- Weight loss
- Fatigue
This condition requires immediate medical evaluation.
2. Post-Infectious Cough (After Viral Infection)
After a cold, flu, or COVID-like illness, the airway lining remains inflamed and sensitive.
Features
- Dry, irritating cough
- Worse at night
- Triggered by cold air or talking
- Can last 3–8 weeks
The infection is gone, but airway hypersensitivity persists.
3. Whooping Cough (Pertussis)
A bacterial infection common in children but also seen in adults.
Symptoms
- Severe repeated coughing fits
- “Whoop” sound when inhaling
- Vomiting after coughing
- Exhaustion
Cough may persist for 2–3 months.
4. Chronic Sinus Infection (Sinusitis)
Sinus infections can cause cough through postnasal drip.
Mechanism
Mucus drips from the nose to the throat and triggers the cough reflex.
Associated symptoms
- Throat clearing
- Nasal blockage
- Headache
- Worse at night or morning
5. Bronchitis (Chronic or Recurrent Infection)
Repeated airway infection causes inflammation of the bronchi.
Symptoms
- Wet cough with mucus
- Chest tightness
- Breathlessness
- Wheezing
6. Pneumonia (Unresolved or Atypical)
Sometimes pneumonia does not fully resolve and leads to prolonged cough.
Symptoms
- Persistent productive cough
- Fever
- Chest pain
- Fatigue
7. Fungal Lung Infections
Seen in:
- Immunocompromised patients
- Diabetics
- Long-term steroid users
Symptoms
- Chronic cough
- Breathlessness
- Weight loss
- Low-grade fever
Other Non-Infectious Conditions That Mimic Infection
Not all chronic coughs are infectious. Common non-infectious causes include:
- Asthma
- Acid reflux (GERD)
- Smoking-related lung disease
- Medication side effect (ACE inhibitors)
Warning Signs (See a Doctor Immediately)
Seek medical care if cough is associated with:
- Blood in sputum
- Weight loss
- Fever > 2 weeks
- Breathlessness
- Chest pain
- Persistent hoarseness
- Night sweats
Diagnosis
Doctors may perform:
- Chest X-ray
- Sputum examination
- TB testing
- CT scan chest
- Pulmonary function tests
- Blood tests
Treatment
Treatment depends on the cause:
Bacterial infections: antibiotics
TB: long-term anti-tuberculosis therapy
Post-viral cough: inhalers, anti-inflammatory medicines
Sinus infection: nasal therapy and medication
Fungal infection: antifungal drugs
Self-medicating cough syrups alone is not sufficient.
Prevention
- Vaccinations (pertussis, flu)
- Good hand hygiene
- Avoid smoking
- Proper nutrition
- Early treatment of respiratory infections
- Wearing masks in high-risk areas
Conclusion
Chronic cough is not just a minor irritation — it is often a signal from the lungs that something is wrong. Infections such as tuberculosis, sinusitis, bronchitis, and pertussis are important causes and should be properly evaluated.
Early diagnosis prevents complications and protects others from contagious diseases. If a cough lasts longer than a few weeks, it deserves medical attention.
