Cough That Will Not Go Away — Causes and Tests
Also described as chronic cough, long-standing cough, cough for weeks.
A cough lasting more than three weeks needs assessment, and one lasting more than two weeks with fever, night sweats or weight loss should be tested for tuberculosis, which remains common in India. Coughing blood needs same-day review. Iswarya Hospital's Pulmonology department, OMR Chennai, investigates with imaging and lung function testing.
🚨 Get emergency care if you have
- •Coughing up blood, even a small amount
- •Cough with fever, night sweats and weight loss
- •Cough with breathlessness at rest or chest pain
- •A change in a long-standing smoker's cough
- •Cough with hoarseness lasting more than three weeks
What causes persistent cough?
Post-infectious cough
A dry cough lingering for weeks after a viral illness. Common and self-limiting.
Asthma
Cough that is worse at night, on exercise or in cold air, often with wheeze.
Tuberculosis
Cough beyond two weeks with fever, night sweats and weight loss. Curable, and tested for with sputum and chest X-ray.
Acid reflux
A dry cough that is worse at night or on lying down, with a sour taste or burning.
COPD
A productive cough with progressive breathlessness, usually in smokers.
How it is investigated
- ✓Chest X-ray
- ✓Sputum testing for tuberculosis where the cough has lasted over two weeks
- ✓Spirometry for asthma and COPD
- ✓CT chest when the X-ray is unclear or symptoms persist
Not every patient needs every test. The consultation decides which of these apply to you.
Frequently asked questions
How long is too long for a cough?▼
Three weeks is the usual threshold for investigation. But a cough of more than two weeks with fever, night sweats or weight loss should be tested for tuberculosis sooner, and coughing blood warrants same-day assessment regardless of duration.
Why do I still cough weeks after the infection cleared?▼
Airway inflammation can persist for six to eight weeks after a viral infection, causing a dry cough long after the illness itself has gone. This is common and usually settles. It is worth reviewing if it is worsening, or comes with breathlessness, fever or blood.
This page is general health information, not a diagnosis or a substitute for a consultation. Symptoms overlap between harmless and serious conditions, and only an examination can tell them apart. If you are worried, see a doctor.
Plan your first visit
Not sure which specialist to see? Tell our care team the reason for your visit and we will help you choose.
- Bring previous prescriptions, relevant test reports or scan images, a medication list and photo ID.
- If you plan to use insurance, bring your policy details. OPD, tests and admission benefits depend on your individual plan and approval.
- Your first consultation determines which tests or treatments are needed; not everyone needs every test listed on this page.
Appointments are requests until confirmed. In a medical emergency, call 044 2025 2025 or go to the nearest emergency department.