Description

• Chronic cough is defined as a cough that persists for >8 weeks in adults.
• In children, chronic cough is often defined as a cough of >4 weeks in duration.
• Subacute cough describes a cough lasting 3 to 8 weeks.
• Patients present because of fear of the causative illness (e.g., cancer), annoyance, self-consciousness, and hoarseness.
• System(s) affected: gastrointestinal (GI), pulmonary

Epidemiology

• Predominant age: all age groups
• Predominant sex: male = female, with females more likely to seek out medical attention

Incidence
Persistent unexplained cough occurs in up to 10% of patients presenting with chronic cough and up to 46% referred to specialty cough clinics.

Prevalence
Chronic cough is one of the most common reasons for primary care visits.

Etiology and Pathophysiology

Varies with findings and disorders implicated

• Often multiple etiologies, but most are related to bronchial irritation. Frequent etiologies (account for >90% of cases) in nonsmokers include the following:
  • Upper airway cough syndrome (UACS) and other upper airway abnormalities, including allergic and vasomotor rhinitis syndromes
  • Chronic rhinitis with postnasal drip (allergic, nonallergic, chronic sinusitis, etc.)
  • Postviral cough
  • Asthma
  • Gastroesophageal reflux disease (GERD)
• Other causes:
  • ACE inhibitors
  • Chronic smoking or exposure to smoke or pollutants
  • Aspiration
  • Bronchiectasis
  • Infections (e.g., pertussis, tuberculosis)
  • Nonasthmatic eosinophilic bronchitis (NAEB)
  • Cystic fibrosis
  • Sleep apnea
  • Restrictive lung diseases
  • Neoplasms: bronchogenic or laryngeal
  • Psychogenic (habit cough)
• Cough hypersensitivity syndrome defines a syndrome of cough with characteristic trigger symptoms not adequately explained by other medical conditions.
• Etiologies of chronic cough in young children differ from those in older children and adults with asthma, protracted bacterial bronchitis, and UACS as most common causes (1),(2).

Risk Factors

Although various conditions may contribute to chronic cough, the main causes include smoking and pulmonary diseases.

Commonly Associated Conditions

Patients with UACS, asthma, and GERD may present with chronic cough as the only symptom and not the usual symptoms associated with the diagnoses.