What is the appropriate management for a patient presenting with a chronic dry cough, clear lung sounds, and stable vital signs (VSS)?

Management of Chronic Dry Cough with Clear Lung Sounds and Stable Vitals

Begin empiric treatment with a first-generation antihistamine-decongestant combination targeting upper airway cough syndrome (UACS), as this is the most common cause of chronic cough in patients with normal examination findings. 1, 2

Initial Mandatory Workup

Before starting empiric therapy, obtain:

• Chest radiograph to exclude malignancy, infection, or structural abnormalities 2, 3
• Spirometry with bronchodilator response to identify reversible airflow obstruction suggesting asthma 2
• Medication review specifically for ACE inhibitors, which must be discontinued if present 1, 2
• Smoking history with immediate cessation counseling if applicable 1, 2

Sequential Empiric Treatment Algorithm

Step 1: Treat UACS (Most Common Cause)

• Start oral first-generation antihistamine-decongestant combination 1, 2
• Allow minimum 1-2 weeks for response 2
• UACS, asthma, and GERD account for >80% of chronic cough cases with normal chest radiographs 2, 4

Step 2: If Cough Persists - Evaluate for Asthma

Critical point: Cough-variant asthma commonly presents with entirely normal physical examination and spirometry 1

• Perform methacholine challenge testing if available - this is the preferred diagnostic approach 1, 2
• A negative methacholine challenge essentially excludes asthma (very high negative predictive value) 1, 2
• If methacholine testing unavailable: Give 2-week trial of oral corticosteroids (e.g., prednisone) 2
• If corticosteroids improve cough, confirm diagnosis with inhaled corticosteroids and bronchodilators 1

Step 3: If Cough Still Persists - Treat GERD

• Initiate empiric proton pump inhibitor therapy 2
• Requires minimum 3 months of intensive acid suppression for adequate trial 2
• GERD-related cough often occurs without typical gastrointestinal symptoms 2
• Consider adding prokinetic agent (metoclopramide) and dietary modifications if initial PPI therapy fails 1

Critical Management Principles

Use additive, sequential therapy - do not stop previous treatments when adding new ones, as >50% of patients have multiple simultaneous causes 1, 2

When Initial Approach Fails

If all three common causes have been adequately treated without resolution:

• High-resolution CT chest to evaluate for bronchiectasis, interstitial lung disease, or occult malignancy 1, 2, 5
• Bronchoscopy to detect endobronchial lesions, sarcoidosis, eosinophilic bronchitis, or occult infection 1, 2
• Consider referral to specialist cough clinic before labeling as "idiopathic" 1, 2

Common Pitfalls to Avoid

• Inadequate treatment duration: Each empiric trial requires sufficient time (1-2 weeks for UACS/asthma, 3 months for GERD) 2
• Stopping previous therapy when adding new treatment: Maintain all treatments as causes are often multifactorial 1, 2
• Relying on spirometry alone to exclude asthma: Normal spirometry does not rule out cough-variant asthma 1, 2
• Dismissing GERD without typical reflux symptoms: Cough may be the only manifestation 2
• Premature advanced imaging: Reserve CT for failed empiric therapy or specific clinical suspicion, not routine use 5, 3