What is the initial evaluation and treatment for a patient presenting with a dry cough?

Evaluation of Dry Cough

Begin with a chest radiograph and spirometry as mandatory first-line tests, while simultaneously assessing for ACE inhibitor use, smoking status, and red flag symptoms that would indicate serious underlying disease. 1, 2, 3

Initial Clinical Assessment

The medical history should specifically identify:

• ACE inhibitor use – discontinue immediately if present, as cough resolves within days to 2 weeks (median 26 days) 3
• Smoking status – cessation leads to resolution within 4 weeks in most patients 1, 3
• Red flag symptoms requiring urgent evaluation: hemoptysis, age >45 years with new/changed cough pattern, prominent dyspnea, hoarseness, systemic symptoms (fever, night sweats, weight loss), trouble swallowing, recurrent pneumonia, or history of tuberculosis/cancer/AIDS 2, 3

Physical examination should concentrate on:

• Upper airway (nasal discharge, throat clearing, postnasal drip sensation, nasal congestion) 3
• Lung auscultation for wheezing or crackles 1
• Signs of systemic illness 1

Mandatory Initial Testing

All patients require: 1, 2, 3

• Chest radiograph (achieves diagnosis in 82-93% when part of standardized protocols) 2
• Spirometry with bronchodilator response 1, 3

Duration-Based Classification and Treatment Algorithm

Acute Cough (<3 weeks)

First determine if this represents pneumonia, pulmonary embolism, or the typical self-limiting viral upper respiratory infection. 1 In the absence of serious illness, patients report benefit from over-the-counter preparations, though evidence for specific pharmacological effect is limited. 1

Subacute Cough (3-8 weeks)

Determine if postinfectious or non-infectious origin. 3, 4 If postinfectious, consider:

• Inhaled ipratropium as first-line therapy 3
• Inhaled corticosteroids if ipratropium fails 3
• Short course oral prednisone for severe paroxysms after ruling out other causes 3

If non-infectious, proceed with chronic cough algorithm below. 4

Chronic Cough (>8 weeks)

Use sequential empiric treatment trials for the three most common causes, treating each adequately before moving to the next: 3

Step 1: Upper Airway Cough Syndrome (UACS)

• Clinical pointers: nasal discharge, throat clearing, postnasal drip sensation, nasal congestion, rhinorrhea 3
• Treatment: First-generation antihistamine-decongestant combination for 1-2 weeks 3, 4
• If no response, proceed to Step 2

Step 2: Asthma/Bronchial Hyperresponsiveness

• Clinical pointers: cough worsens at night, with cold air exposure, or with exercise 3
• Testing: If spirometry normal, perform bronchoprovocation challenge 1, 3
• Treatment: Inhaled bronchodilators and inhaled corticosteroids 3, 4
• Response timeline: improvement within 1 week, complete resolution may take up to 8 weeks 3
• Alternative approach if testing unavailable: 2-week trial of oral corticosteroids; if no response, eosinophilic airway inflammation is unlikely 1
• If no response, proceed to Step 3

Step 3: Gastroesophageal Reflux Disease (GERD)

• Important: GERD-related cough may occur without gastrointestinal symptoms 1
• Treatment: High-dose PPI therapy, dietary modifications, lifestyle changes 3
• Response timeline: may require 2 weeks to several months, some patients need 8-12 weeks before improvement 3
• If inadequate response: add prokinetic agent (metoclopramide) and rigorous dietary adherence before labeling as medically refractory 1

Critical principle: Sequential and additive therapy is crucial because more than one cause may be present simultaneously. 1

Advanced Evaluation (Only After Adequate Therapeutic Trials Fail)

Proceed to advanced testing only after completing adequate trials of UACS, asthma, and GERD treatment: 3

1. High-resolution CT (HRCT) chest to evaluate for bronchiectasis (28% of cases with normal radiographs), bronchial wall thickening (21%), interstitial lung disease, or occult masses 2, 3

   • Note: Wide application of CT in all chronic cough patients has low clinical yield; reserve for selected cases 2

2. 24-hour esophageal pH monitoring if empiric GERD therapy failed (to detect nonacid reflux) 1, 3

3. Bronchoscopy to evaluate for endobronchial lesions, sarcoidosis, eosinophilic bronchitis, lymphocytic bronchitis, or occult infection 1, 3

Management of Refractory Chronic Cough

Only diagnose unexplained/idiopathic cough after completing systematic evaluation and adequate therapeutic trials of all common causes, plus ruling out uncommon causes. 1, 3

Treatment options for truly refractory cough:

• Gabapentin: start 300mg once daily, escalate as tolerated to maximum 1,800mg daily in divided doses 3
• Multimodality speech pathology therapy as reasonable alternative 3
• Low-dose morphine: may be considered but carries addiction risk 3

Common Pitfalls to Avoid

• Inadequate treatment duration: Each therapeutic trial must be given sufficient time (1-2 weeks for UACS, up to 8 weeks for asthma, 8-12 weeks for GERD) 3
• Premature advanced testing: Ordering HRCT or bronchoscopy before completing empiric treatment trials wastes resources 2, 3
• Missing ACE inhibitor-induced cough: Always review medications first 3
• Ignoring multiple simultaneous causes: Treat sequentially and additively rather than stopping one treatment when starting another 1
• Relying on cough characteristics for diagnosis: Timing and characteristics have little diagnostic value 1, 4