Red flag symptoms - Persistent cough

The possible red flag symptoms that may indicate a more serious cause for persistent cough, plus advice on taking an occupational history and when to refer to secondary care for more detailed imaging.

Persistent cough: Ask patients about other symptoms, such as chest pain
Persistent cough: Ask patients about other symptoms, such as chest pain

Coughs are a common presentation in primary care and the majority will prove to be self-limiting respiratory tract infections. However, more sinister diagnoses may present with this common symptom.

A detailed exploration of the problem and how it affects the patient is essential.

Red flag symptoms

  • Persistent cough for more than three weeks
  • Pleuritic chest pain
  • Dyspnoea
  • Haemoptysis
  • Persistent nocturnal cough
  • Wheeze
  • Recurrent chest infections
  • Coughing up phlegm every morning for more than three months of the year
  • Unintentional weight loss
  • History of night sweats


The history is crucial to establishing the diagnosis. Aetiologies comprise respiratory pathology and non- respiratory pathology.

An exploration of the patient's thoughts concerning the cough, their underlying concerns and expectations, will allow a holistic approach to management.

The patient's age will guide the history, as will the duration of the cough (chronic cough is defined as cough for more than three weeks).

A detailed smoking history is essential and can be quantified in pack-years. If the patient smokes, find out if they have made any attempts to quit. This may provide a chance for opportunistic health promotion and signposting to smoking cessation services.

An occupational history may provide clues to the diagnosis. Certain diagnoses may be related to certain chemicals in the patient's place of work. Ask if there has been any exposure to asbestos or if there is a history of pigeon racing.

Questions to ask

To obtain a useful history, ask the patient the following questions:

  • Can the patient describe the cough?
  • How long have they had the cough for?
  • Is it worse at any particular time of day?
  • Is it worse at work?
  • Are there any associated symptoms such as difficulty breathing, expectorate, haemoptysis, chest pain or wheeze?
  • Has the patient noticed any unintentional weight loss?
  • Is there a history of foreign travel to TB-prevalent areas?
  • Have they been exposed to TB?

If the patient has noticed any one of these symptoms, a detailed exploration of the symptom is essential.

These questions aim to establish a respiratory cause of cough, but there are multiple non-respiratory causes and it may be necessary to enquire about indigestion, orthopnoea, ankle swelling and any sensation of postnasal drip, and to review the medications the patient is taking.


Examination must be focused and will be guided by the history. Initial observations will include checking the respiratory rate and if there is any evidence of respiratory distress (intercostal recession in children or difficulty in completing sentences).

Is there a fever? Pulse oximetry will allow determination of oxygen saturations.

Examination may also include checking for clubbing, peripheral cyanosis or CO2 retention flap. Respiratory causes of clubbing include lung cancer, TB, bronchiectasis, interstitial lung disease, pulmonary fibrosis and empyema. COPD does not cause clubbing.

It may be necessary to examine the throat and palpate for lymphadenopathy, or to auscultate for heart sounds if heart failure is suspected. Percuss the chest wall to exclude an effusion and auscultate the lung fields checking for air entry, added sounds or rhonchi.


Investigations in primary care may include:

  • FBC, U&Es, CRP, LFTs
  • Chest X-ray
  • Peak flow diary (home/work)
  • Pulmonary function tests
  • Echocardiogram
  • Sputum testing for microscopy, culture and sensitivity
  • ECG
  • Helicobacter pylori stool antigen

When to refer

Refer to secondary care for more detailed imaging, such as high resolution CT, diagnostic uncertainty, persistent cough where primary care investigations may have revealed nothing and when symptoms are not settling despite initiation of treatment in primary care.

A suspected malignancy must be referred on the two-week wait rule. Acute referral may also be necessary if the patient is systemically unwell.1 

Possible causes

  • Acute respiratory tract infection (bronchitis/tracheitis): generally a dry cough that is self-limiting after a few weeks
  • Pneumonia: cough, fever, shortness of breath, pleuritic chest pain. Some crepitations/bronchial breathing likely on examination
  • Bronchial malignancy: persistent cough, haemoptysis, weight loss, shortness of breath, pleuritic chest pain. There may be some appetite loss or night sweats. There may be a strong smoking history.
  • TB: haemoptysis, cough, shortness of breath, history of foreign travel.
  • Pertussis: persistent paroxysms of cough, worse at night. Adults tend to be less systemically unwell. Cough can last for a few months.
  • Bronchiectasis: cough, shortness of breath, with copious amounts of very thick sputum. Examination may reveal clubbing and coarse bilateral crepitations.
  • COPD: productive persistent cough, shortness of breath, wheeze and a strong smoking history.
  • Asthma: cough worse at night, exercise-induced cough, shortness of breath or wheeze. Family history of asthma and/or eczema.
  • Left ventricular systolic dysfunction
  • Postnasal drip
  • GORD
  • Medications (ACE inhibitors)
  • Idiopathic
  • Psychogenic

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  • Dr Singh is a GP in Northumberland


NICE Suspected cancer: recognition and referral. NG12 June 2015. Updated July 2017.

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