Is there an algorithm for diagnosing chronic cough in adults?

13 Jun 2022

What the research says:

Chronic cough in adults is defined as a cough persisting for at least 8 weeks. Chronic cough is a presenting symptom for a wide range of conditions although four conditions account for the majority of cases: upper airway cough syndrome, gastroesophageal reflux disease (GERD), asthma and nonasthmatic eosinophilic bronchitis (Michaudet & Malaty 2017). Red flags that should raise suspicion for an underlying, potentially malignant, pathology include associated fever, weight loss, haemoptysis, hoarseness, excessive dyspnoea or sputum production, recurrent pneumonia, a smoking history of 20 pack years or a smoker older than 45 years (Irwin et al 2018). Initial treatment should focus on the underlying cause (if one is found). A detailed and systematic approach is therefore required. A number of evidence-based algorithms for the diagnosis of chronic cough in adults are available (Irwin et al 2018; Iyer et al 2013; Kardos et al 2020; Morice et al 2019).

Adults (Irwin et al 2018; Iyer et al 2013; Kardos et al 2020; Morice et al 2019 ; Satia et al 2021): Cough duration >8 weeks

Evaluate for red flags that may indicate an underlying potentially malignant pathology

Undertake a detailed history and physical examination:

  • Cough duration, description and timing (morning, evening, indoor, outdoor)
  • Impact and triggers
  • Family history
  • Cough score (VAS or verbal out of 10). Consider other tools such as the Leicester cough questionnaire
  • Assess associated symptoms
  • Assess for potential causes:
    • Upper airway cough syndrome
    • GERD/reflux
    • Asthma
    • Nonasthmatic eosinophilic bronchitis
    • ACE inhibitor-associated cough
    • COPD
    • Smoking
    • Lung tumour
    • Hypersensitive cough
    • Interstitial lung disease
    • Tuberculosis (consider regional epidemiology)
    • Aspiration
    • Cardiac causes
    • Unclassified cough (no apparent cause)

Obtain chest X-ray

Next steps:

  • Spirometry
  • PFT (if indicated by spirometry)
  • FeNO (if available)
  • Blood eosinophils


Further evaluations may be necessary, if clinically indicated, including:

  • CT chest
  • Echocardiogram
  • Sputum cultures
  • Sputum for AFB
  • Sinus imaging
  • GI referral (scope, ph monitoring)
  • Respiratory referral for sputums or bronchoscopy





Initial management Treat specific cause and if cough is improved continue for 3 months after which withdrawal can be considered
No improvement
  1. Review adherence to prescribed therapies
  2. Consider other factors such as inhaler technique
  3. Evaluate for other potential diagnoses
  4. Consider referral for specialist evaluation

AFB, acid-fast bacillus; COPD, chronic obstructive pulmonary disease; CT, computerized tomography; GERD, gastroesophageal reflux disease; PFT, pulmonary function test; VAS, visual analogue scale.

What this means for your clinical practice:

  • All people with cough of at least 8 weeks duration should have chest x-ray
  • Undertake a thorough history, physical examination and additional testing as clinically indicated to identify specific causes and treat accordingly
  • Begin by evaluating for red flags that may raise suspicion for an underlying malignant pathology
  • Consider trial of pharmacotherapy if no underlying cause/trigger identified (unexplained chronic cough)
  • Refer for specialist evaluation if no improvement after a trial of pharmacotherapy (unexplained/refractory chronic cough)

With grateful thanks to Dr Alan Kaplan (Chair Family Physician Airways Group of Canada) for and on behalf of the IPCRG practice driven answers review group.

Useful links and supporting references:

Irwin RS, et al. Classification of cough as a symptom in adults and management algorithms. CHEST guideline and Expert Panel report. Chest 2018;153:196–209.

Iyer VN, Lim KG. Chronic cough: an update. Mayo Clin Proc 2013;88:1118.

Kaplan A. Chronic cough in adults: Make the diagnosis and make a difference. Pulm Ther 2019;5:11-21. Available at: Accessed April 2021.

Kaplan A. Improving the assessment of adults with chronic cough in primary care. Available at: Accessed April 2022.

Kardos P, et al. German Respiratory Society guidelines for diagnosis and treatment of adults suffering from acute, subacute and chronic cough. Respir Med 2020;170:105939. (Available at:; pay-per-view)

Michaudet C, Malaty J. Chronic cough: evaluation and management. Am Fam Phys 2017;96:575–80.

Morice AH, et al. ERS guidelines on the diagnosis and treatment of chronic cough in adults and children. Eur Respir J 2019;55.

Satia I, et al. Chronic cough: Investigations, management, current and future treatment. Can J Respir Crit Care Sleep Med 2021;5:404-16. Available at: Accessed April 2022

Resource information

Respiratory conditions
  • Cough
Respiratory topics
  • Diagnosis
Type of resource
IPCRG COVID-19 and respiratory Q&A