Introduction
Acute cough (<3 weeks) is common, usually self-limiting, and due to a viral infection. Cough may persist for longer in more severe infection such as COVID-19 or community-acquired pneumonia. Chronic cough in adults (a cough lasting >8 weeks) is common in primary care (UK prevalence 5%),1 and is associated with impaired quality of life and significant healthcare costs.
Recent British Thoracic Society guidance on chronic cough in adults2 outlines a pragmatic and evidence-based approach (Figure 1). After the exclusion of common disease and aggravants, cough may be due to one or several observable ‘treatable traits’ (Figure 2).
Figure 1. Management of chronic cough in primary care. 2WW = 2-week wait. ACEI = angiotensin-converting enzyme inhibitor. AFB = acid-fast bacillus test. BEC = blood eosinophil count. COPD = chronic obstructive pulmonary disease CXR = chest X-ray. FBC = full blood count. FeNO = fractional exhaled nitric oxide. ICS = inhaled corticosteroids. ILD = interstitial lung disease. PPI = proton pump inhibitor. TB = tuberculosis. © British Thoracic Society. Used with permission.
Figure 2. Treatable traits in chronic cough. ACEI = angiotensin-converting enzyme inhibitor. © British Thoracic Society. Used with permission.
History and examination
The history and examination should help identify common causes and aggravants, and red-flag symptoms requiring urgent referral (Figure 1).
Some symptoms may identify specific traits such as episodic wheeze in airways obstruction, heartburn, or rhinitis. Productive cough is managed differently from dry cough, and airway disease (particularly bronchiectasis) should be considered. GPs should consider tuberculosis in patients at higher risk such as immunosuppressed patients and higher-risk ethnic groups.
Common aggravants include angiotensin-converting enzyme inhibitors (ACEIs) and smoking. Whooping cough may occur in immunised adults and is suggested by paroxysms of dry coughing ending in retching/vomiting, often without the characteristic ‘whoop’.
Any environmental factors may trigger cough such as indoor or outdoor pollution (including second-hand tobacco smoke) and exposure to dust or fumes, including occupational exposure.
Triggering of the cough with food, phonation, or certain smells such as perfume may suggest the presence of cough hypersensitivity syndrome (see below).
Chronic cough has a big impact on quality of life (GPs should ask, ‘How does the cough affect you?’). Stress urinary incontinence occurs in both sexes but is particularly common in females (30%–50% of females with chronic cough).3 Cough syncope can result in serious injury and accidents. Any patient who experiences cough syncope should be advised not to drive (6 months for 1 episode, 12 months for ≥2) and to inform the Driver and Vehicle Licensing Agency.4
Which tests should be carried out in primary care?
All patients with chronic cough should have a chest X-ray and spirometry. Urgent referral should not be delayed if there are red-flag features.
Eosinophilic airway disease can be indicated by a full blood count and fractional exhaled nitric oxide (FeNO). Sputum microbiology is useful in the presence of persistent productive cough to look for evidence of airway infection.
Identification of common aggravants (ACEI medication and smoking)
Regardless of other causes, ACEI should always be stopped in patients with cough. They should be replaced with an angiotensin 2 receptor blocker (ARB) but patients should be warned that any improvement in cough can take 4 weeks.
Smoking cessation may initially worsen a cough because nicotine suppresses cough. This can be ameliorated, and quit rates improved with nicotine replacement therapy. Suspected occupational cough should be referred to secondary care.
Identification and optimised treatment of underlying disease and common ‘treatable traits’ that may cause or aggravate cough
GPs should not give empirical treatment in the absence of objective evidence of disease. Objective evidence can include symptoms (heartburn and rhinitis) or biomarkers such as blood eosinophil count, for example. The link between cough and certain traits (smoking, ACEI, and airway disease) is well established, whereas for others (reflux, upper airway disease, obesity, and obstructive sleep apnoea) the relationship is more controversial.
Airways disease
Asthma/chronic obstructive pulmonary disease should be treated according to national guidelines.5,6 Evidence of a blood eosinophil count ≥0.3 × 109/L and/or FeNO >25 ppb is suggestive of eosinophilic airways disease and can prompt a 4-week trial of inhaled corticosteroid (for example, budesonide 200 mcg b.d. for 1 month).
Gastro-oesophageal reflux
Most trials of proton pump inhibitors in cough are negative. Heartburn may predict response to treatment (for example, lansoprazole 30 mg b.d. for 1 month) but response rate is low (28%).7 There is no evidence for the use of alginates or prokinetics.
Chronic rhinosinusitis
Symptoms and signs of nasal blockage should be sought. A minimum 6-week trial of intranasal steroid and nasal douching can be tried, but evidence for helping cough is sparse. Referral to ear, nose, and throat should be considered if there is no improvement after 12 weeks.
Obstructive sleep apnoea and obesity
These have been linked with cough, although evidence of cough improvement when treating these conditions is limited.
Cough hypersensitivity
Cough hypersensitivity should only be diagnosed after exclusion of aggravants and optimised management of other identified traits. It can occur alongside other traits or when no other ‘cause’ of cough is evident.
It characteristically affects middle-aged females, and sufferers report typical symptoms such as laryngeal paraesthesia/irritation and dry cough in response to usually innocuous stimuli such as eating, talking, or exposure to environmental irritants, for example, change in air temperature or fumes or sprays.8
Pharmacological treatments include ‘off label’ use of low-dose morphine (MST 5 mg b.d.), gabapentin, pregabalin, and amitriptyline, but use is often limited by side effects and better initiated in secondary care (except for palliative care). Newer pharmacological agents are in development and clinical trials in progress. Non-pharmacological treatments by speech therapists are increasingly used and are effective.9
Simple treatments such as sipping water, honey, and over-the-counter remedies may benefit patients. Evidence for over-the-counter remedies is limited, and most are no better than placebo.
Referral to secondary care
Patients who continue to cough despite treatment should be referred if there is suspected disease such as lung cancer, bronchiectasis, interstitial lung disease, heart failure, and tuberculosis. Patients with red-flag symptoms should be referred urgently.
Summary
Chronic cough is a common condition that can significantly impair quality of life. British Thoracic Society guidance proposes a systematic approach (Figure 1): 1) thorough clinical assessment; 2) identification and treatment of underlying disease; 3) eliminating common aggravants (smoking and ACEI use); and 4) identification and treatment of relevant traits (Figure 2). Empirical/blind treatment of common causes is no longer recommended. Most cough can be dealt with in primary care. GPs should refer on to secondary care if there are ongoing symptoms after assessment and treatment, or where there is concern about serious underlying disease.
Notes
Provenance
Freely submitted; externally peer reviewed.
Competing interests
Kevin Gruffydd-Jones has worked as an unpaid advisor for AstraZeneca on their global and national chronic obstructive pulmonary disease policy committees. Sean Parker has received advisory fees from TREVI and Merck.
- © British Journal of General Practice 2024
