What is the best approach to diagnose and manage a patient with a chronic cough?

Chronic Cough: Diagnostic and Management Approach

For patients with chronic cough (lasting >8 weeks), systematically evaluate and empirically treat the three most common causes in sequence: Upper Airway Cough Syndrome (UACS), asthma, and gastroesophageal reflux disease (GERD), as these account for the vast majority of cases and frequently coexist. 1

Initial Assessment and Red Flags

Start by obtaining a focused history targeting:

• ACE inhibitor use – discontinue immediately if present, as cough resolves in days to 2 weeks (median 26 days) 2, 3
• Smoking status – counsel cessation, as 90% of chronic bronchitis patients resolve cough after quitting 3
• Signs of serious disease – fever, weight loss, hemoptysis, recurrent pneumonia warrant immediate chest CT 4

Obtain a chest radiograph in all patients to exclude malignancy, heart failure, and parenchymal lung disease 1, 5. Normal chest x-ray findings are typical in the three most common causes 1.

Critical point: Cough characteristics (timing, quality, sputum production) have no diagnostic value and should not guide your approach. 1

Sequential Empiric Treatment Algorithm

Step 1: Treat UACS First (1-2 Week Trial)

Begin with a first-generation antihistamine/decongestant combination (e.g., brompheniramine with sustained-release pseudoephedrine) 1, 2, 3.

• First-generation antihistamines are required; newer non-sedating antihistamines are ineffective 3
• Expect response within 1-2 weeks, though complete resolution may take several weeks 3
• If no response, obtain sinus imaging to evaluate for chronic sinusitis, which can be clinically silent 1

UACS can present with cough alone ("silent postnasal drip") without typical upper airway symptoms. 1

Step 2: Add Asthma Treatment (2-4 Week Trial)

If cough persists after treating UACS, initiate inhaled corticosteroids combined with long-acting β-agonists 2, 6.

• Asthma commonly presents as isolated cough ("cough variant asthma") with normal spirometry 1
• Consider bronchoprovocation challenge if available, or proceed with empiric treatment 6
• Assess response over 2-4 weeks 3

Also consider Non-Asthmatic Eosinophilic Bronchitis (NAEB):

• Presents with normal spirometry and no airway hyperresponsiveness 1
• First-line treatment is inhaled corticosteroids 1, 2
• Requires sputum eosinophil testing or bronchoscopy for definitive diagnosis 1

Step 3: Add GERD Treatment (1-3 Month Trial)

If cough persists despite addressing UACS and asthma, initiate proton pump inhibitor therapy with dietary modifications 2, 3.

• GERD can cause cough without typical reflux symptoms ("silent GERD") 1
• Requires prolonged trial of 1-3 months to assess response 3
• Add prokinetic therapy if inadequate response to PPI alone 2

Critical Management Principles

Use sequential AND additive therapy – do not discontinue partially effective treatments when adding the next intervention, as multiple causes frequently coexist 1, 2, 3. This is the most common management error.

Maintain all partially effective treatments for several months to achieve complete cough resolution 3.

Refractory Chronic Cough

If cough persists after 4-6 weeks of sequential empiric treatment for all three common causes:

1. Consider bronchoscopy to evaluate for occult endobronchial disease (tumor, sarcoidosis, eosinophilic bronchitis) 1
2. Obtain high-resolution chest CT if not already performed 5, 4
3. Refer to a cough specialist before labeling as unexplained/idiopathic cough 1

For symptomatic relief in refractory cases:

• Low-dose morphine is preferred for idiopathic chronic cough 2
• Codeine or dextromethorphan for short-term symptomatic relief 1, 2
• Consider gabapentin or pregabalin for cough hypersensitivity syndrome 4, 7

Common Pitfalls to Avoid

• Do not treat only one cause – approximately 25% of patients have multiple contributing factors 1, 3
• Do not use second-generation antihistamines for UACS – they are ineffective 3
• Do not expect rapid GERD response – requires 1-3 months of treatment 3
• Do not rely on patient symptom descriptions to guide diagnosis 1
• Do not perform extensive testing upfront – empiric sequential treatment is more cost-effective and has higher diagnostic yield 1, 7