What is chronic cough?
What is chronic cough?
Cough is a fundamental, protective reflex in response to airway irritation.1,2 However, when a cough persists for months or even years despite thorough clinical examination and adequate treatment of cough-associated conditions, it is time to consider chronic cough as a diagnosis.1,2
Cough classification
Cough is a medical problem that can be evaluated by its duration, characteristics, severity, aetiology, pathophysiologie, or treatment response.3 Chronic cough is defined as a cough that persists > 8 weeks, according established guidelines.1,4
Refractory or unexplained chronic cough (RCC)
persistent cough despite thorough investigation and/or treatment according to published practice guidelines1
Chronic cough affects approximately 1 in 10 people worldwide (based on a pooled analysis of 90 studies).5
Patients are typically women in their 50s (based on a retrospective study of 10,032 patients).1
Identifying the cause of chronic cough
When faced with a patient struggling with a persistent cough with a duration of > 8 weeks, it is important to rule out other diagnoses before moving on to a diagnosis of refractory chronic cough or unexplained chronic cough.1,4,6,7
Chronic cough is often associated with an underlying condition, such as GERD, asthma, UACS, and NAEB. If the treatment of an underlying condition does not resolve the cough, or an underlying condition cannot be identified, there are two types of chronic cough to consider:1,4,6,7
Refractory chronic cough
a type of chronic cough that persists despite thorough investigation and conventional treatment of cough-associated conditions or traits.
Unexplained chronic cough
a chronic cough with no underlying aetiology identified, despite a thorough diagnostic workup.
Comorbid cough-associated conditions most commonly found in these patients:8
Asthma and nonasthmatic eosinophilic bronchitis (NAEB)
Gastroesophageal reflux disease (GERD)
Postnasal drip syndrome / upper airway cough syndrome (UACS) secondary to rhinosinusitis disease
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References:
- Morice AH, Millqvist E, Bieksiene K, et al. ERS guidelines on the diagnosis and treatment of chronic cough in adults and children. Eur Respir J 2020;55(1):1901136.
- Satia I, Badri H, Al-Sheklly B, Smith JA, Woodcock AA. Towards understanding and managing chronic cough. Clin Med (Lond) 2016;16(Suppl 6):s92–s97.
- McGarvey L, Gibson PG. What is chronic cough? Terminology. J Allergy Clin Immunol Pract 2019;7(6):1711-1714.
- Irwin RS, French CL, Chang AB, Altman KW; CHEST Expert Cough Panel. Classification of cough as a symptom in adults and management algorithms: CHEST guideline and expert panel report. Chest 2018;153(1):196-209.
- Song WJ, et al. The global epidemiology of chronic cough in adults: a systematic review and meta-analysis. Eur Respir J 2015;45:1479–1481.
- Gibson P, Wang G, McGarvey L, et al. Treatment of unexplained chronic cough: CHEST Guideline and Expert Panel Report. Chest 2016;149(1):27-44.
- Muccino D, Green S. Update on the clinical development of gefapixant, a P2X3 receptor antagonist for the treatment of refractory chronic cough. Pulm Pharmacol Ther 2019;56:75-78.
- Mazzone SB, McGarvey L. Mechanisms and Rationale for Targeted Therapies in Refractory and Unexplained Chronic Cough. Clin Pharmacol Ther. 2021 Mar;109(3):619-636.
