Long-lasting cough and unexplained breathlessness
A cough that has lasted for weeks, or breathlessness whose cause you do not know, is not a diagnosis. It is a symptom with many possible causes. This page explains which causes are common, who should be seen, how a doctor looks for the cause and which signs are urgent.
Cough and breathlessness are symptoms, not diagnoses
Cough is the way the body clears the airways. Breathlessness means breathing has become harder than usual. Neither is the name of a disease. For a lung doctor the main job is to find the cause.
The NHS says most coughs follow a cold or flu and clear up by themselves in three to four weeks. A cough that lasts more than three weeks is called persistent and should be looked into.
Common causes
The NHS names these causes of cough: colds and flu, smoking, acid reflux, allergy (such as hay fever), infections such as bronchitis or COVID, and mucus dripping from the back of the nose into the throat.
For breathlessness: asthma, chest infection, being overweight, smoking and anxiety are common; COPD, lung fibrosis (scarring in the lungs), heart failure and lung cancer are less common but more serious. This is why you should not diagnose yourself.
A cough with unexplained weight loss, fever and night sweats, or blood in the phlegm should be taken seriously. For tuberculosis, the NHS gives “a cough lasting more than three weeks” as the main symptom. TB can be treated with antibiotics and anyone can catch it.
Who should be seen?
Make an appointment if:
- Your cough has lasted more than three weeks.
- You get breathless with activity or when lying down, or it has gradually got worse.
- The cough comes with wheezing, unexplained weight loss, fever or night sweats, or swollen ankles.
- You have heart or lung disease or a weakened immune system (such as diabetes) and the cough has not gone away (NHS).
- You smoke cigarettes or hookah and your morning cough and phlegm have changed.
If there is coughing up of blood, severe breathlessness or chest pain, go to the section “When to get urgent help”.
How is it assessed?
A lung doctor usually starts with questions and an examination: when the cough began, whether it is dry or brings up phlegm, whether it is worse at night or in the day, what makes it worse, smoking and hookah, work and exposure to dust, medicines, reflux and allergy. Then, depending on the symptoms, one of the following may be requested (in general, not necessarily all):
- Chest X-ray or CT scan. The NHS says a CT scan gives a more detailed picture and usually takes 10 to 20 minutes. Some CT scans use contrast (a dye). If you have a drug allergy or a kidney problem, tell the imaging centre.
- Spirometry. A simple test that measures the air you breathe out. The NHS says the centre doing the test will tell you before the test to avoid smoking, heavy meals or alcohol for some hours, and whether to stop your inhalers.
- A phlegm sample to look for infection.
- Blood tests, allergy tests or further tests such as bronchoscopy, only if needed. We explain these in general terms on this page; where and when they are done is for the doctor to say.
What does treatment generally look like?
Treatment depends on the cause. A few general examples:
- Asthma: controller and reliever inhalers. See the page “Asthma and respiratory allergy”.
- COPD: stopping smoking, bronchodilator inhalers and rehabilitation. See the page “COPD”.
- Allergy and mucus from the nose: avoiding the trigger, and medicines such as antihistamines and nasal sprays chosen by a doctor or pharmacist (NHS).
- Reflux: the doctor assesses and treats it.
- Infection: antibiotics only on a doctor’s advice. The NHS reminds us that a viral infection does not get better with antibiotics.
- Other causes: TB with antibiotics, lung fibrosis with specific treatments under a specialist (NHS).
If you are already taking a medicine, such as a steroid or an inhaler, do not stop it just because your cough has improved, unless your doctor has said so.
What can you do yourself?
- Stop smoking cigarettes and hookah. Hookah is not a safe alternative to cigarettes (CDC). Smoking itself makes a cough worse (NHS).
- Drink plenty of fluids and rest. The NHS says warm lemon and honey may soothe the throat, though the evidence is limited.
- Reduce triggers such as smoke and dust.
- Write down when the cough is worse and what sets it off. This note helps the doctor.
- Gather your earlier films and reports before you go.
- Do not take leftover cough medicine or antibiotics on your own.
When to get urgent help
- Call 115 (Iran’s emergency number) if you cannot finish a sentence, your lips or nails have turned blue, you suddenly feel confused, you are coughing up a lot of blood, or you have sudden breathlessness with chest pain or swelling of one leg.
- Be seen the same day if you have a severe cough that is getting worse, fever with breathlessness, or you have noticed a few streaks of blood in your phlegm. The NHS treats these as urgent.
- If you cannot reach your doctor, go to the emergency department of the nearest hospital.
See the full list in the guide “When to call urgently”.
Frequently asked questions
My cough has lasted three weeks. Should I be worried?
The NHS says most coughs clear up by themselves within three to four weeks, and a cough that lasts more than three weeks should be seen. Concern is reasonable, but in most cases the cause is common and treatable. The NHS also points out that a cough is rarely a sign of something serious such as lung cancer. Even so, you cannot be sure without an examination.
Should I take antibiotics to get rid of my cough?
No, unless a doctor decides they are needed. The NHS says antibiotics are not usually prescribed for a cough and are only needed for a bacterial infection or when there is a risk of complications. They do nothing for a viral infection. If your doctor prescribes antibiotics, finish the course.
Do cough syrups or tablets work?
The NHS says shop-bought cough medicines do not stop a cough and may only reduce it a little. Evidence for honey and warm lemon is also limited, though they may soothe the throat. Honey must not be given to a baby under one year. If a cough lasts, find the cause instead of relying on medicine.
My cough is worse only at night or after meals. What is the cause?
The NHS lists acid reflux, allergy, asthma and mucus dripping down the back of the nose among the causes of cough. A night cough with wheezing points more towards asthma. The diagnosis needs an assessment, so do not take medicines on a guess.
I am only breathless on stairs. Do I have a lung disease?
Not necessarily. The NHS lists the common causes of breathlessness as asthma, chest infection, being overweight, smoking and anxiety, and the more serious ones as COPD, lung fibrosis, heart failure and lung cancer. Treatment depends on the cause, so do not diagnose yourself. If breathlessness gets worse with activity or lying down, or your ankles are swollen, see a doctor.
What should I bring with me?
Films and reports of earlier X-rays and CT scans, earlier spirometry, blood tests, a list of your medicines and allergies, your inhalers themselves, and a note of when the cough started, the times it is worse, and your smoking, hookah and work history. See the guide "First visit".