What is a persistent cough?

A cough is a natural defence mechanism that helps protect the respiratory system. It clears mucus, germs and other irritants from the airways, helping keep the lungs healthy. Most coughs caused by viral infections improve within one to three weeks. However, a cough that persists beyond this period may require medical evaluation to identify the underlying cause.

Based on how long it lasts, healthcare providers generally classify a cough as:

Acute cough: Lasts for less than three weeks and is commonly associated with conditions such as colds, flu or other respiratory infections.
Subacute cough: Lasts for three to eight weeks and may occur during recovery from a respiratory infection.
Chronic cough: Persists for more than eight weeks in adults or more than four weeks in children and may be linked to conditions such as asthma, allergies, acid reflux or other respiratory disorders.

7 signs your persistent cough may be more than 'just a cold'

1. It has lasted longer than 3 weeks

In India, this is where doctors start thinking about tuberculosis. India still accounts for about a quarter of the world's TB cases, and the national programme treats a cough of over two weeks as reason enough to test. The other usual suspects: asthma, chronic bronchitis, airway irritation left by an infection, early COPD, or the dust and smoke you breathe daily.

2. You get breathless easily

Climbing just two flights of stairs or carrying a bag of vegetables home leaves you breathless now. Breathlessness alongside a cough can mean your lungs aren’t working as well as they should: perhaps the airways are inflamed, oxygen isn’t getting through efficiently, or early COPD or untreated asthma is at play.

They start taking the lift, slowing their pace, or passing on the cricket match. But stamina doesn’t just slip away with age: it’s your body’s way of asking for attention.

3. You bring up phlegm every day

If you’re coughing up mucus every day, especially in the first hour after you wake, it’s a sign that inflammation has moved in for good. It is common among smokers and ex-smokers, and anyone working around dust, fumes or chemicals.

Chronic bronchitis is defined as this pattern, namely sputum on most days for three months in two consecutive years. See a doctor the same week if there is blood in the phlegm or if it turns thick, green, or brown.

4. Every cold turn into a long illness

Some people catch a cold and bounce back in four days. Others cough for a month, then catch the next one going around the office. If minor infections keep turning into long ones, your lungs may not be cleared properly.

That can mean low lung capacity, ongoing inflammation, weak airway clearance, or asthma and early COPD nobody has looked for. Three chest infections a year are a pattern.

5. Chest tightness or wheezing

If there's a tight band across your chest, or a thin whistle as you breathe out, it means air is squeezing through narrowed tubes. It’s one of the clearest signs that your cough is not caused by a cold.

It suggests asthma, COPD, a hyperreactive airway after infection, allergy, or exposure to cold air and pollution. Many adults in India are diagnosed with asthma late because they never wheezed loudly. They felt just trapped and tired.

6. You cough when nobody else is coughing

This is a symptom that people don’t often report, because it sounds too small to mention Harmless things trigger the cough reflex and it may be the cough reflex that is the problem and not the lungs. Doctors call this cough hypersensitivity syndrome, or neurogenic cough and it is often associated with a tickly, irritable feeling in the larynx.

7. When it is impacting your quality of life

Chronic cough can sometimes ruin your social life, even affecting your self-esteem and mental health. It can affect other aspects of your health like giving you sore abdominal and rib muscles, insomnia and exhaustion. It can get so bad that you could end up feeling depressed and isolated.

What causes a persistent cough?

Airway disease: asthma, cough-variant asthma, chronic bronchitis, COPD, and bronchiectasis
Infections: TB, pneumonia, whooping cough, and airway sensitivity left by a virus
Nose and sinuses: post-nasal drip from allergic rhinitis or sinusitis.
Acid reflux: stomach acid reaching the throat and voice box, often with no heartburn
What you breathe: cigarette and beedi smoke, cooking-fire smoke, pollution, and workplace dust
Medicines: ACE inhibitor blood pressure tablets, which is a known cause of dry cough
Serious causes: lung cancer, interstitial lung disease, and heart failure

How do doctors diagnose a persistent cough?

Your doctor may recommend different tests depending on your symptoms, medical history and examination.

Chest X-ray: Looks for infections, lung abnormalities, or other causes of a persistent cough.
Sputum test for TB: Examines mucus from the lungs using a rapid molecular test to detect tuberculosis bacteria.
CT scan of the chest: Provides detailed images of the lungs when an X-ray does not provide enough information.
Bronchoscopy: A thin, flexible camera is passed into the airways to examine them directly and, when needed, collect samples for testing.

How to manage a persistent cough?

Knowing how long a cough has lasted and whether other symptoms are present can help you decide when to manage it at home and when to seek medical care. A cough persisting for 1–2 weeks is often associated with a viral infection or a common cold. This can be usually managed with adequate rest, hydration and appropriate over-the-counter remedies. If the cough continues for 3–8 weeks, it may be due to post-viral airway inflammation, allergies or an underlying respiratory condition. Hence, it is advisable to schedule a non-urgent appointment with a doctor for evaluation.

Certain symptoms require more immediate attention. Shortness of breath at rest can indicate a potentially serious breathing problem and should be assessed by a doctor immediately. Similarly, chronic cough with blood is not a symptom to ignore, as it can occur with severe infections, damage to the airways or lungs, or other serious conditions. Seek urgent medical attention if you cough up blood, particularly if the bleeding is significant or accompanied by breathlessness or chest pain.

Alongside that:

Stop smoking and get away from other people's smoke.
Ventilate the kitchen, and use cleaner cooking fuel if you can
Use your inhaler daily if prescribed, not only when you feel bad.

Why choose Narayana Health?

Narayana Health's pulmonology teams evaluate long-standing coughs with everything under one roof: spirometry, imaging, molecular TB testing, and bronchoscopy. Our pulmonologists also work alongside ENT, gastroenterology, allergy, and cardiology, which matters because a stubborn cough often has two causes running together.

Conclusion

A cough that lingers after a cold is not always something to simply wait out. If it lasts beyond three weeks, keeps returning, or comes with breathlessness, wheezing, daily phlegm, blood, fever, weight loss or chest pain, it deserves medical attention. The good news is that most persistent coughs have an identifiable and treatable cause.

Finding that cause early can prevent a minor airway problem from becoming a long-term one. If your cough is not steadily improving, get it assessed rather than masking it with cough syrups.

FAQs

Q. Is it serious if I have a cough but no other symptoms?
A. Usually not, if it fades within a couple of weeks. But a lone cough past 3 weeks needs review. Cough-variant asthma, reflux, post-nasal drip and early TB can each show up as a cough and nothing else.

Q. What are the bad signs of a cough?
A. Blood in the phlegm, weight dropping without trying, returning fever or night sweats, breathlessness while sitting still, chest pain and a changed voice. Any of these, or a cough worsening after three weeks, means you should see a doctor now.

Q. Which type of cough is normal?
A. A cough that follows a cold, peaks early, then eases week by week is normal, even if it takes two to three weeks to finish. Direction matters more than the calendar.

Q. Is coughing worse at night?
A. Often, yes. Lying flat lets mucus drain into the throat and acid travel up, and airway function dips to its lowest around 4 am. Being woken by coughing is a classic sign of poorly controlled asthma.

Q. Does a long-lasting cough affect your voice?
A. It can. Repeated coughing strains the vocal cords, leaving hoarseness, and throat pain. Reflux and postnasal drip also irritate the voice box. Hoarseness beyond three weeks needs checking.