What is the appropriate workup and treatment for a 23-year-old male with a chronic dry cough and no upper respiratory infection (URI) symptoms?

Chronic Dry Cough Workup and Management in a Young Adult Male

A systematic approach with chest radiography, spirometry with bronchial challenge testing, and empiric treatment trials is the recommended approach for a 23-year-old male with chronic dry cough without URI symptoms. 1

Initial Diagnostic Workup

1. Chest Radiography

   • Essential first step to rule out structural abnormalities 2, 1
   • Should be performed before proceeding with further investigations

2. Medication Review

   • Check for ACE inhibitors which are a common cause of chronic dry cough 2
   • Assess for other medications that may cause cough

3. Smoking/Environmental Assessment

   • Evaluate smoking status and occupational exposures 2, 1
   • Assess for marijuana use or cooking smoke exposure

4. Pulmonary Function Testing

   • Spirometry to assess for airflow obstruction 1
   • Bronchial challenge testing (methacholine challenge) even with normal spirometry 2, 1
   • Fractional exhaled nitric oxide (FeNO) to assess for eosinophilic inflammation 1

Targeted Investigations for Common Causes

Upper Airway Cough Syndrome (UACS)

• Evaluate for post-nasal drip, throat clearing, nasal congestion 2
• Consider sinus imaging if first-line treatment fails 2

Asthma/Non-asthmatic Eosinophilic Bronchitis

• Perform methacholine inhalation challenge (MIC) testing 2
• Measure sputum eosinophils if available 2

Gastroesophageal Reflux Disease (GERD)

• Assess for heartburn, regurgitation, or silent reflux symptoms 2
• Consider empiric PPI trial if symptoms present 2

Treatment Algorithm

1. First-Line Treatment: Upper Airway Cough Syndrome

   • Trial of first-generation antihistamine/decongestant combination for 2-4 weeks 2
   • Example: Brompheniramine with sustained-release pseudoephedrine 2
   • Note: Newer generation non-sedating antihistamines are ineffective for cough 2

2. Second-Line Treatment: Asthma/Bronchial Hyperresponsiveness

   • If UACS treatment fails, initiate inhaled corticosteroids and bronchodilators for 4 weeks 2
   • For suspected cough-variant asthma despite normal spirometry, consider short course of inhaled corticosteroids 1

3. Third-Line Treatment: GERD

   • If asthma treatment fails, trial of proton pump inhibitor with lifestyle modifications for 4-8 weeks 2, 1
   • Note: PPI should not be prescribed if workup for acid reflux is negative 2

4. Fourth-Line Treatment: Refractory Cough

   • Consider neuromodulators like gabapentin (starting at 300mg daily, titrating up to 1800mg/day in divided doses) 2
   • Speech pathology therapy for cough suppression techniques 2
   • High-resolution CT chest if cough persists after treating common causes 1

Important Clinical Pearls

• Multiple causes may coexist in up to 25% of patients with chronic cough 3
• Treatment should be sequential and additive as more than one cause may be present 2
• Cough may take 2-3 weeks to resolve completely after initiating appropriate treatment 1
• Adequate hydration is important for effective mucus clearance 1
• Warning signs requiring immediate attention: hemoptysis, breathlessness, prolonged fever 1

Follow-up Recommendations

• Reassess response to each treatment trial before proceeding to the next step
• If cough persists after systematic approach, consider referral to pulmonologist
• For unexplained chronic cough persisting >8 weeks despite appropriate evaluation, consider specialized cough clinic referral 4

This systematic approach identifies and treats the most common causes of chronic cough in young adults while minimizing unnecessary testing and interventions.