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You’ve had it for two months. The cold that started it is long gone, your throat feels fine in the morning, and still the cough keeps arriving on schedule: at night, in meetings, halfway through a laugh.
A cough is a reflex worth having. It clears the airway. But when it sticks around for eight weeks or more, it stops being the tail end of an infection and starts being a clue to something else. Doctors call that a chronic cough, and it affects roughly one in ten adults. In non-smokers with a normal chest X-ray, three conditions explain most cases. The rest of the list is where it gets interesting, and where a lot of people go years without an answer.
What Counts as a Chronic Cough?
Eight weeks for adults, four weeks for children. That threshold matters because it separates a lingering post-viral tickle from a problem worth investigating. Most coughs after a respiratory infection settle within three to four weeks. If yours is still going strong at week nine, the original virus is no longer the explanation.
Doctors tend to work through the list below in order of likelihood rather than drama. It’s also worth saying plainly that a cough this persistent reshapes daily living long before anyone finds a cause: lost sleep, urine leakage in women who’ve had children, pulled intercostal muscles, missed work. Research into how chronic conditions reshape daily living keeps finding the same pattern, where the symptom burden lands months before the diagnosis does.
1. Post-Nasal Drip (Upper Airway Cough Syndrome)
Mucus running down the back of the throat tickles cough receptors, and the result is a dry, repetitive cough that often turns productive first thing in the morning. It’s the single most common cause of chronic cough in adults, usually driven by allergies, chronic sinusitis, or non-allergic rhinitis triggered by cold air, perfume or smoke.
What it usually feels like
Constant throat clearing. A tickle behind the soft palate. A cough that’s worse when you first lie down or first wake up. Many people insist they feel no drip at all, which is why the modern name is upper airway cough syndrome: it’s the irritation that matters, not the sensation.
Treatment is usually a nasal steroid spray for four to six weeks, saline rinses, and an antihistamine if allergy is behind it. Be careful with decongestant sprays, which cause rebound congestion after about three days of use.
2. Asthma, Including Cough-Variant Asthma
Most people picture asthma as wheezing and breathlessness. A sizeable minority never wheeze at all. Cough-variant asthma produces a dry, stubborn cough and almost nothing else, and it tends to flare at night, after exercise, in cold air, or after laughing hard.
Confirmation comes from spirometry before and after a bronchodilator, sometimes a methacholine challenge. In practice, a six to eight week trial of inhaled corticosteroids often serves as both the test and the treatment. If the cough disappears and then returns when the inhaler stops, you have your answer.
3. Acid Reflux (GERD)
This is the cause that surprises people, mostly because around half of those with reflux-related cough never get heartburn. Stomach contents creep up as far as the larynx, which is far more sensitive than the oesophagus, and the result is a cough that worsens after meals, when lying flat, or in the early morning. A hoarse voice and a bitter taste on waking are useful clues.
The standard approach is an eight to twelve week course of a proton pump inhibitor alongside changes like finishing meals three hours before bed, raising the head of the bed, and losing weight if it’s relevant. Reflux cough is slow to improve. Two weeks of omeprazole proves nothing either way.
4. Smoking and COPD
A daily cough with sputum, present for years, is the classic picture of chronic bronchitis and the long-term lung diseases that quietly narrow your airways. It gets dismissed as a smoker’s cough, which is a mistake. By the time the cough is routine, measurable airflow obstruction is often already there, and spirometry will show it in minutes.
Stopping smoking slows the decline at any stage, and it’s the only intervention that reliably does. Inhalers ease symptoms but don’t undo the damage.
5. Blood Pressure Medication
ACE inhibitors such as lisinopril, ramipril and enalapril cause a dry, tickly, hacking cough in somewhere between 5 and 20 per cent of people who take them. Women are more often affected. The timing is what makes it sneaky: the cough can start days after the first dose or many months later, by which point nobody connects the two.
Switching to an ARB such as losartan usually resolves it within one to four weeks. Anyone already being monitored for high blood pressure and the complications of leaving it untreated should have their full medication list reviewed before anyone orders a CT scan.
6. Lingering Infections and Bronchiectasis
Whooping cough is the one people forget. In adults it rarely produces the telltale whoop; instead you get violent coughing fits that end in vomiting or a gasping breath, and the whole thing can run for three months. It’s among the most contagious diseases circulating in the community, and a nasal swab or PCR test settles it.
Bronchiectasis is another possibility: airways damaged by past infection or inflammation that no longer clear mucus properly. The giveaway is a daily cough producing large volumes of sputum, plus repeated chest infections. It needs a high-resolution CT to diagnose, and airway clearance techniques to manage.
7. Lung Cancer and Other Serious Disease
Cancer is a rare cause of chronic cough overall, but it’s the one you cannot afford to miss. A cough that changes character, comes with blood, hoarseness, or unexplained weight loss, especially in a smoker over 40, needs imaging promptly. Lung cancer sits high on the list of the most common cancers and the warning signs worth knowing, partly because early disease is so often silent.
Heart failure deserves a mention too. A persistent dry cough that worsens when lying flat, paired with breathlessness on exertion or swollen ankles, points at fluid in the lungs rather than anything in the airway itself.
Red Flags That Shorten the Timeline
Most chronic coughs are benign and treatable. A handful of features mean you should be seen within days rather than weeks:
- Coughing up blood, even a streak
- Unexplained weight loss or loss of appetite
- New breathlessness at rest, or breathlessness that’s getting worse
- Fever, night sweats, or drenching sweats
- Chest pain with the cough
- Hoarseness lasting more than three weeks
- Any new cough in a current or former smoker over 40 that lasts beyond three weeks
How the Investigation Usually Unfolds
A good GP or respiratory physician works in sequence rather than ordering everything at once. History first, with specific questions about timing, triggers, medications, reflux symptoms and occupational exposure. Then a chest X-ray and spirometry, which rule out a surprising amount for very little cost.
From there it’s often a series of treatment trials: a nasal steroid, then an inhaled corticosteroid, then a proton pump inhibitor, each given long enough to work. Stopping an ACE inhibitor is a four-week experiment that costs nothing. If nothing shifts, a CT scan of the chest, a scope of the upper airway, or 24-hour pH monitoring comes next.
The practical takeaway is that a cough lasting months is rarely a mystery to medicine, even when it feels like one to you. It just needs to be worked through in the right order, with someone asking the right questions about what you take, what you breathe, and what your cough sounds like at three in the morning.
