Refractory chronic cough: why it persists and how it is assessed

The NHS says most coughs clear up on their own within 3 to 4 weeks. A cough that goes on much longer deserves assessment. A guideline written by respiratory clinicians for NHS Highland divides cough by duration: acute cough is present for less than three weeks, subacute cough for three to eight weeks, and chronic cough for more than eight weeks.

The same guideline defines chronic refractory cough as a chronic cough with unexplained cause despite full investigation, smoking cessation and removal of medicines that could be responsible, and which has not responded to treatment. This is a diagnosis reached after other explanations have been tried, not a first assessment.

The NHS says to see a GP if you have had a cough for more than 3 weeks, you are losing weight for no reason, or you have a weakened immune system, for example because of chemotherapy or diabetes. It says to ask for an urgent GP appointment or get help from NHS 111 if your cough is very bad or quickly worsens, you feel very unwell, you have chest pain, the side of your neck feels swollen and painful, you find it hard to breathe, or you are coughing up blood.

The NHS says a cough is rarely a sign of something serious such as lung cancer, but it is the reason clinicians take persistent symptoms seriously. The NHS Highland guideline lists unexplained coughing up blood, new finger clubbing, persistent or recurrent chest infections, and unexplained symptoms lasting more than three weeks such as a changed cough, breathlessness, chest or shoulder pain, loss of appetite or weight loss as features for the urgent suspected cancer pathway, and advises a repeat chest X-ray in some cases to confirm that an abnormality has cleared.

The NHS says most coughs are caused by a cold or flu and lists other causes including 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. For chronic cough the NHS Highland guideline lists a wider set to exclude or treat.

The NHS says a GP may listen to your chest, take a mucus sample, order an X-ray, allergy test or lung function test, or occasionally refer you to hospital. The NHS Highland guideline describes a comprehensive history covering duration, triggers, variation through the day, red flag symptoms, associated chest, throat and infective symptoms, reflux and heart failure symptoms, smoking, occupation, travel and environmental factors, and a drug history to exclude a medicine as the cause. It recommends spirometry and a chest X-ray, and examination of the chest, heart, ears and throat.

The guideline also advises measuring the effect on quality of life, for example with the Leicester Cough Questionnaire, and asking about stress urinary incontinence, depression and anxiety, and interference with speech. It notes that fainting during coughing (cough syncope) means informing the DVLA and stopping driving.

For suspected chronic refractory cough, the NHS Highland guideline advises routine referral to a respiratory service for consideration of neuromodulator medicines and possible clinical trial involvement. Their use for cough is a specialist decision. The guideline does not give doses or a ranking of options, and neither does this page.

Referral to a cough clinic is therefore a logical next step once treatable causes have had a fair trial. Before referral it is helpful to bring a list of medicines tried, how long each was used, and whether the cough changed, because many guideline pathways rely on trials with review points of 2 to 8 weeks.

The NHS Highland guideline gives patient-facing techniques, which can be useful alongside medical assessment:

• Breathe through your nose as much as you can rather than your mouth, building up slowly.

• If a cough is coming on, swallow hard, relax your shoulders and breathe slowly and gently out.

• Retrain your breathing pattern to use the diaphragm rather than the shoulder and neck muscles.

• Take regular sips of water to keep the throat moist, or suck a sweet.

• If the urge to cough builds, cough once only with a hand over the mouth and lips closed, swallow or sip water, then breathe out gently, pinch the nose and pause the breath for 5 to 10 seconds.

The NHS says cough syrups, sweets and medicines will not stop a cough, though they may help you cough less, and decongestants and cough medicines containing codeine will not stop it either. Honey and lemon and herbal products have limited evidence. It also says antibiotics are not normally prescribed for coughs and are used only if there is a bacterial infection or a risk of complications. Ask a pharmacist before taking any remedy if you are pregnant or have other conditions.

Chronic cough is first assessed by a GP, with chest X-ray and spirometry, and referral to NHS respiratory services if it persists. Private respiratory consultants can arrange tests and review sooner. Ask whether treatable causes have been checked, what the plan is if tests are normal, and whether any proposed medicine is being used outside its licence, and what monitoring it needs.