Chronic Cough
Cause
Cough receptors are triggered by mechanical (touch, displacement, acid) or chemical (cold, hot, chemicals) signals.
Subacute cough = 3 to 8 weeks
Post-infectious cough (viral, pertussis, COVID-19)
Exacerbation of underlying disease (asthma, COPD, rhinitis)
Chronic cough = >8 weeks
Asthma
Non-asthmatic eosinophilic bronchitis
GORD
GORD in OSA
Laryngopharyngeal Reflux LPR
COPD
Upper Airway Cough Syndrome formerly Postnasal drip
Medication cough (ACEI, Ca2+ blockers + Bisphonates > GORD, Latanoprost)
Prolonged postinfectious cough (Mycoplasma, Chlamydia, Pertussis, SARS, COVID-19)
Bacterial bronchitis
Chronic bronchitis
Bronchiectasis
Interstitial lung disease
Lung cancer
Aspiration (swallowing dysfunction with recurrent aspiration, foreign body)
Chronic heart failure
Vagal nerve irritation
Central airways compression from AVM and masses
Laryngeal sensory neuropathy
Chronic tonsillar enlargement
Arnold “ear cough” reflex due to foreign body or wax impaction
Premature ventricular contractions
Holmes-Adie syndrome is anisocoria and hyperhidrosis
Somatic cough disorder
Chronic refractory cough
Diagnostic algorithm
Treat if history and exam suggest UACS, asthma, GORD, infection, other obvious cause
If not obvious then CXR and treat if cause identified
If no cause then investigate or trial treatment for the most common causes
UACS (2 to 4 weeks trial INGCs, can consider 1st gen antihistamine e.g. Doxylamine)
Asthma (20 to 30% of cases - trial 4 weeks Inhaled GCs)
NAOB (10 to 30% of cases - trial 8 weeks Inhaled GCs)
GORD (2-month trial PPI)
Pertussis (20% of cases)
Unexplained chronic cough
Speech therapy, breathing exercises
Trial Inhaled GCs
Trial Ipratropium
Gabapentin or pregabalin
Reference
UpToDate - Evaluation and treatment of chronic cough [Needs Log In]
UpToDate - Causes subacute and chronic cough in adults [Needs Log In]
UpToDate - Cough evaluation algorithm [Needs Log In]
Murtagh’s Ddx - Chronic cough
Murtagh’s Ddx - Cough in kids
