Dry cough: causes, red flags and when to seek help

A dry, or non-productive, cough is one where nothing is brought up. It is typically triggered by irritation of the airway lining rather than by mucus that needs clearing. After a viral infection the lining can stay sensitive for weeks, so a tickle in the throat, a change of air temperature, laughing or talking can set off bouts long after the other symptoms have gone.

The NHS says a cough will usually clear up on its own within 3 to 4 weeks, which is longer than many people expect. That is the point at which clinicians begin to look for other explanations.

The NHS says most coughs are caused by a cold or flu, and lists smoking, heartburn (acid reflux), allergies such as hay fever, infections such as bronchitis or COVID-19, and mucus dripping down the throat from the back of the nose as other causes.

• The NHS lists wheezing, coughing, shortness of breath and a tight chest as the main symptoms of asthma, which can be worse at night and early in the morning.

• Some blood pressure medicines in the ACE-inhibitor group are known to cause a persistent dry cough; do not stop them without speaking to your prescriber.

The NHS says to ask for an urgent GP appointment or get help from NHS 111 if your cough is very bad or quickly gets worse, for example a hacking cough or one you cannot stop, if you feel very unwell, have chest pain, find it hard to breathe, are coughing up blood, or have a painful swollen neck gland.

The NHS lung cancer pages list a cough that is not going away, shortness of breath, coughing up blood, chest or shoulder pain, repeated chest infections, unexplained weight loss, loss of appetite and tiredness among common symptoms, and a hoarse voice that does not go away among the less common ones. It says to see a GP if you have had a cough for longer than 3 weeks and to call 999 or go to A&E if you are struggling to breathe or have pain in your chest or upper back.

A sudden severe cough with choking, noisy breathing, swelling of the lips or face, or wheeze after eating or a sting suggests an allergic reaction or blocked airway and is an emergency.

The NHS says the GP might listen to your chest with a stethoscope, take a sample of any mucus you cough up, order an X-ray, an allergy test or a lung function test, or, rarely, refer you to hospital to see a specialist.

Expect questions about how long the cough has lasted, whether it is worse at night or after eating, smoking history, medicines, occupational dust or fumes, recent infections, heartburn, nasal symptoms, and any weight loss or night sweats. A chest X-ray is the usual first test when a cough has lasted beyond three weeks, and spirometry is used when asthma or chronic lung disease is suspected.

The NHS suggests rest, plenty of fluids, and staying at home away from other people if you have a high temperature. It mentions hot lemon and honey, noting this is not suitable for babies under one year and that evidence for it is limited, and a herbal medicine called pelargonium for people aged 12 or over, again with limited evidence.

A pharmacist can talk about cough syrups, medicines and sweets, which the NHS says will not stop the cough but may help you cough less. It says decongestants and cough medicines containing codeine will not stop a cough. Stopping smoking, steam or humid air, and keeping a glass of water by the bed are simple, low-risk measures.

Your GP is the first contact. If tests suggest asthma, you will usually be started on treatment and followed up by the practice nurse. A chest physician or respiratory department deals with unexplained or difficult coughs, and an ear, nose and throat or gastroenterology opinion may help when the cause is thought to be postnasal drip or reflux.