A Cough That Will Not Go: When to Worry and What Causes It
A cough that lasts more than eight weeks is called a chronic cough, but in Pakistan the number that matters is two weeks: anyone coughing for two weeks or longer should be tested for tuberculosis, because this is one of the highest-burden countries in the world and TB is both transmissible and curable. The test to ask for is a sputum sample sent for a rapid molecular test, along with a chest X-ray. Once TB is excluded, the great majority of long coughs come from one of four things: post-nasal drip from the nose and sinuses, asthma, acid reflux from the stomach, or a blood-pressure tablet from the ACE inhibitor group, which causes a dry tickly cough in up to one adult in ten who takes it. Smoking and air pollution drive many of the rest. A cough with coughing up blood, weight loss, drenching night sweats, fever for more than two weeks, hoarseness lasting over three weeks, or breathlessness needs urgent assessment rather than another cough syrup. Most long coughs can be sorted out with a careful history, a chest X-ray, a sputum test and a trial of treatment aimed at the likeliest cause.
Health writers · Aslam Clinic
How long is too long
Doctors divide cough by duration, because duration is the most useful clue to the cause. Under three weeks is acute, and is nearly always a . Three to eight weeks is subacute, and is most often the tail of an infection that has already passed. More than eight weeks in an adult is , and needs a cause found rather than another course of tablets.
That eight-week definition is what British, European and American guidelines use, and you will meet it if you read about cough anywhere else. It is not the threshold this article uses for deciding when to test. Pakistan's National TB Control Programme and WHO both screen at two weeks, and in a country with one of the world's largest tuberculosis burdens that is the right number. Waiting another six weeks before thinking about TB means six more weeks of a person coughing bacteria into a shared room.
Tuberculosis: the one not to miss
Tuberculosis is an infection of the lungs, and sometimes other organs, caused by a slow-growing . It spreads through the air when someone with untreated lung TB coughs, sings or speaks. Pakistan reports several hundred thousand cases a year and is consistently among the highest-burden countries in the world. A large share of those cases are never diagnosed, and undiagnosed people keep transmitting.
The classic picture is a cough of two weeks or more, weight loss, evening fever, night sweats, tiredness and loss of appetite, sometimes with blood in the sputum. But the classic picture is not universal. People with — very common here — and people with HIV often present atypically, and early TB can be a cough and nothing else. That is exactly why the screening rule is duration-based rather than symptom-based.
The test. Ask for a sputum sample to be sent for a rapid molecular test, usually Xpert MTB/RIF or Xpert Ultra. It gives an answer in hours, detects far more cases than the older sputum smear under a microscope, and simultaneously reports whether the organism is resistant to rifampicin, the key first-line drug. WHO has recommended it as the initial diagnostic test since 2013 and Pakistan's national programme supplies it free. A chest X-ray is done alongside it. Blood sugar and an HIV test are usually offered at the same time, because both change the treatment.
The treatment. TB is curable in the great majority of people. Standard treatment is a combination of several antibiotics taken together for at least six months, provided free through the national programme, with the first two months being the intensive phase. People usually feel much better within three to four weeks — and that improvement is the danger point, because it is when treatment gets abandoned. Stopping early does not just risk relapse; it selects for drug-resistant organisms, and multi-drug-resistant TB takes far longer to treat, uses harsher drugs and is cured less often. Finish the course. If a side effect makes that difficult — , vomiting, rash, numbness in the feet, or a change in vision — go back to the centre rather than stopping on your own.
Everyone in the household should be checked when a case is confirmed, especially children under five, pregnant women and anyone with diabetes or low immunity. Preventive treatment is offered to close contacts who are infected but not ill. Until the person on treatment has been on it for a few weeks, keeping the room ventilated, covering coughs and sleeping in a separate space where possible all reduce spread.
The other common causes
| Cause | What it feels like | The clue | What settles it |
|---|---|---|---|
| Post-nasal drip from nose or sinuses | Tickle at the back of the throat, constant throat clearing | Blocked or runny nose, worse lying down, worse in dust and pollen season | Nasal steroid spray and saline rinses over several weeks |
| , including cough-variant asthma | Dry cough, worst at night and in the early hours | Wheeze, chest tightness, trigger pattern, or hay fever in the family | An inhaled preventer, with to confirm |
| Cough after meals or on lying down, sour taste, hoarse in the morning | Heartburn, though a third of people with reflux cough have no heartburn at all | Meal timing, weight loss, raising the head of the bed, acid suppression | |
| ACE inhibitor tablets | Dry, persistent tickle with no sputum | Started weeks to months after beginning a blood-pressure medicine ending in -pril | A prescriber switching the drug class; the cough fades over one to four weeks |
| Smoking and smoke exposure | Morning cough with sputum, gradually worsening breathlessness | Any tobacco, sheesha, or a wood or dung cooking fire indoors | Stopping the exposure; to look for COPD |
| Bronchiectasis or old lung damage | Daily sputum, often large amounts, recurrent chest infections | Previous TB, measles or severe childhood pneumonia | A of the chest and long-term airway clearance |
| Lung cancer | New or changed cough, sometimes blood | Over 40, smoker, weight loss, hoarseness, finger clubbing | Urgent chest X-ray and specialist referral |
Two of these deserve a note. The ACE inhibitor cough affects up to one adult in ten taking drugs such as enalapril, lisinopril, ramipril or captopril, is more common in women and in South Asian people, and can begin months after starting the tablet — so it is often not connected to the drug at all. It is harmless but genuinely miserable, and it resolves after a prescriber switches the medicine. Never stop a blood-pressure tablet on your own. Reflux cough is the other trap: many people with it have no heartburn whatsoever, and the only sign is a cough that is worse after meals and on lying flat. Our article on acid reflux and heartburn covers the management.
What the doctor will actually do
A first visit for a long cough should include how long it has lasted, whether anything is coughed up, contact with anyone known to have TB, smoking and workplace exposures, a full list of your medicines, and whether you have heartburn, nasal symptoms, wheeze or weight loss. Examination covers the chest, the neck glands and the nose. The first tests are usually a chest X-ray and a sputum molecular test, with a and blood sugar. follows if asthma is suspected.
If everything is normal, treatment is often a trial aimed at the most likely cause — a nasal steroid spray, an inhaled preventer, or acid suppression — given for a properly long stretch and then judged. This is not guesswork. A cough that responds to a nasal spray over six weeks has effectively been diagnosed by the response. What does not work is two days of a treatment, abandoned because nothing changed; a cough that has been present for months rarely settles in less than several weeks.
What you can do yourself
- Stop smoking, and stop sheesha. Cough from smoking often gets briefly worse in the first weeks of quitting before it improves; that is the airway clearing, not a reason to restart.
- Get the cooking fire out of the living space if you use wood, dung or coal, and ventilate the kitchen.
- Warm fluids, and honey in warm water, genuinely help the irritated-throat component of a cough. Honey should not be given to a baby under one year.
- Steam inhalation over a bowl helps some people with a nasal cause. Keep children well away from the hot water.
- Keep a simple diary: what time of day it is worst, what you were doing, what came up. It will shorten the diagnosis considerably.
- Bring every medicine box, including anything bought without a prescription, to the appointment.
- If you have been given TB treatment, take it every day and complete it. Ask for a treatment supporter if remembering is hard.
What does not help
- Repeat courses of antibiotics. Unless there is a bacterial chest infection, they do nothing for a chronic cough and are a direct contributor to , which is already severe in Pakistan.
- Cough syrups. Over-the-counter suppressants and expectorants have little good evidence in chronic cough. Codeine-containing syrups additionally carry a dependence risk, are misused, and should not be given to children.
- Steroid injections given at a pharmacy or clinic to stop a cough. They suppress symptoms briefly, expose the whole body to steroid, and can mask a TB diagnosis while making the infection worse.
- Waiting to see. Six weeks of a cough that nobody has looked at is six weeks lost if the cause is treatable and transmissible.
When to see a doctor
Make an appointment if a cough has lasted two weeks or more, if it is disturbing your sleep or your work, if you cough up sputum every day, or if it started after a new medicine. Go urgently for blood in the sputum, weight loss, night sweats, fever beyond two weeks, breathlessness, a hoarse voice for over three weeks, or a lump in the neck. Anyone who shares a home with a person being treated for TB should be assessed even without symptoms, and children under five in that household particularly so.
Common questions
Still not sure what to do?
Reading about a symptom only goes so far. A doctor who can ask you questions and examine you will get further in ten minutes than any article can.
