What are the preferred names for chronic cough?

Preferred Names for Chronic Cough

The preferred terminology for chronic cough depends on the clinical context: use "chronic cough" for cough lasting >8 weeks, "unexplained chronic cough (UCC)" when no cause is identified after initial evaluation, "refractory chronic cough (RCC)" when cough persists despite treatment of identified causes, and increasingly "cough hypersensitivity syndrome (CHS)" as the mechanistic framework underlying RCC/UCC. 1, 2

Duration-Based Classification

The foundational classification starts with duration 1:

• Chronic cough: Cough lasting >8 weeks in adults (Grade 2C recommendation)
• This duration threshold is the first step in narrowing differential diagnoses and has been validated globally across four continents

Terminology for Persistent Cough Without Clear Cause

When chronic cough persists despite evaluation and treatment, three overlapping terms exist, though they are not interchangeable 3, 2:

Unexplained Chronic Cough (UCC)

• Cough persisting after comprehensive examination but before therapeutic trials
• No identifiable cause found on initial workup
• Represents 10-42% of chronic cough patients 3

Refractory Chronic Cough (RCC)

• Cough that persists despite treatment of identified underlying causes
• Implies therapeutic trials have been attempted and failed
• More specific than UCC as it indicates treatment resistance 2

Idiopathic Chronic Cough (ICC)

• Older term for cough with no associated or causative diagnosis
• Being phased out in favor of more precise terminology 2, 4

Emerging Mechanistic Framework: Cough Hypersensitivity Syndrome

Cough hypersensitivity syndrome (CHS) is increasingly recognized as the preferred pathophysiological framework for understanding RCC/UCC 3, 4, 5:

• Describes the underlying mechanism: hypersensitive cough reflex to normally innocuous stimuli

• Key clinical features include:

  • Allotussia: Cough triggered by non-tussive stimuli (talking, laughing, eating)
  • Hypertussia: Exaggerated cough response to mild irritants
  • Laryngeal paresthesia: Persistent tickling or irritating throat sensation 4, 5

• CHS focuses on cough symptomatology rather than presumed causes, leading to mechanism-based treatment approaches 4, 5

• This framework has driven development of targeted therapies like P2X3 antagonists (gefapixant) 6, 5

Clinical Coding

In Germany, a new ICD-10 code U69.6 was introduced specifically for RCC/UCC, recognizing these as distinct disease entities 6

Important Caveats

The interchangeable use of ICC, UCC, and RCC in literature creates heterogeneity in study populations 3, 2, making it critical to:

• Use precise terminology in clinical documentation
• Distinguish between cough as a symptom of other diseases (asthma, COPD, GERD) versus cough as a disease entity (RCC/UCC/CHS) 6, 5
• Recognize that traditional causes (upper airway cough syndrome, asthma, GERD, nonasthmatic eosinophilic bronchitis) remain the most common etiologies of chronic cough 1