What are the treatment options for a patient with a persistent dry cough?

Treatment for Persistent Dry Cough

For persistent dry cough, begin with a systematic evaluation to identify and treat the three most common causes—upper airway cough syndrome (UACS), asthma, and gastroesophageal reflux disease (GERD)—which together account for approximately 90% of chronic cough cases, and if cough remains unexplained after adequate therapeutic trials, consider gabapentin or multimodality speech pathology therapy. 1, 2

Initial Diagnostic Approach

Before initiating treatment, determine the duration and exclude serious conditions:

• Cough lasting >8 weeks qualifies as chronic cough and requires systematic evaluation rather than simple symptomatic suppression 1, 2
• Obtain chest radiograph to rule out pneumonia, masses, interstitial disease, or congestive heart failure 3, 2
• Check vital signs including tachycardia, tachypnea, and fever to exclude pneumonia 3
• Assess smoking status, as chronic bronchitis is a leading cause in smokers 2

Systematic Treatment Algorithm

Step 1: Treat Upper Airway Cough Syndrome (UACS)

Start with a first-generation antihistamine/decongestant combination (brompheniramine/pseudoephedrine or chlorpheniramine/phenylephrine) beginning once-daily at bedtime for 2-3 days, then advance to twice-daily to minimize sedation 4, 2

• Add intranasal corticosteroid spray (fluticasone or mometasone) to decrease airway inflammation 4
• Look for clues: nasal discharge, throat clearing, or postnasal drip sensation 2
• Trial duration: 2-3 weeks before declaring treatment failure 4, 2

Step 2: Evaluate and Treat Asthma/Eosinophilic Bronchitis

Perform objective testing for bronchial hyperresponsiveness or initiate a therapeutic trial with inhaled corticosteroids if testing is unavailable 1, 2

• Look for triggers: cold air, exercise, or nighttime worsening 2
• If wheezing is present, prescribe bronchodilators immediately 3
• Do NOT use inhaled corticosteroids if tests for bronchial hyperresponsiveness and eosinophilia are negative 1

Step 3: Treat Gastroesophageal Reflux Disease (GERD)

Initiate high-dose PPI therapy (omeprazole 40 mg twice daily) along with dietary modifications and lifestyle changes 4, 2

• GERD-related cough may require 8-12 weeks for response, so adequate treatment duration is essential before declaring failure 4
• Do NOT prescribe PPIs if objective testing for acid reflux is negative 1
• Consider 24-hour esophageal pH monitoring if GERD remains suspected despite failed empiric therapy 4, 2

Post-Infectious Cough (3-8 Weeks Duration)

If cough follows a recent respiratory infection and persists beyond 3 weeks:

Prescribe inhaled ipratropium bromide 2-3 puffs four times daily, which has the strongest evidence for attenuating post-infectious cough 1, 3, 4

• For severe paroxysms compromising quality of life, consider prednisone 30-40 mg daily for a short, finite period after ruling out other common causes 1
• Antibiotics have NO role in post-infectious viral cough and should not be prescribed 1, 3, 4
• Central acting antitussives (codeine or dextromethorphan) should be considered only when other measures fail 1

Unexplained Chronic Cough (After All Trials Fail)

If cough persists despite adequate trials of UACS, asthma, and GERD treatment:

Prescribe gabapentin starting at 300 mg once daily, escalating as tolerated up to a maximum of 1,800 mg daily in two divided doses 1, 2

• Discuss potential side effects and reassess risk-benefit at 6 months before continuing the drug 1
• Multimodality speech pathology therapy is a reasonable alternative with Grade 2C evidence 1
• Gabapentin has been associated with improvement in quality of life in randomized controlled trials 1

Advanced Diagnostic Testing (If All Empiric Therapy Fails)

• High-resolution CT chest to evaluate for bronchiectasis, interstitial lung disease, or occult masses 4, 2
• 24-hour esophageal pH monitoring if GERD remains suspected 4, 2
• Bronchoscopy to evaluate for endobronchial lesions, sarcoidosis, eosinophilic bronchitis, or occult infection 4, 2

Symptomatic Antitussive Options (Use Sparingly)

For severe cough interfering with sleep or quality of life while awaiting response to specific treatments:

• Dextromethorphan or codeine for cough suppression, particularly at night 1, 3
• Honey and lemon as initial home remedy for productive cough 3
• Guaifenesin (FDA-approved) to help fluidify mucus and bronchial secretions 3
• Avoid over-the-counter cough syrups with subthreshold therapeutic levels of active ingredients 1

Critical Pitfalls to Avoid

• Do NOT prescribe antibiotics for uncomplicated acute or post-infectious viral cough—they provide no benefit and cause harm 1, 3, 4
• Do NOT diagnose "unexplained cough" until completing systematic evaluation of UACS, asthma, and GERD with adequate treatment trials 4, 2
• Do NOT use nasal decongestant sprays for more than 3-5 days due to rebound congestion risk 3, 4
• Do NOT stop therapy prematurely—GERD treatment may require 8-12 weeks, and inadequate treatment duration is a common cause of apparent treatment failure 4, 2
• Do NOT ignore wheezing—it requires evaluation and bronchodilator treatment 3
• Do NOT assume purulent sputum indicates bacterial infection requiring antibiotics 2

Special Consideration: Pertussis

If paroxysmal cough with post-tussive vomiting or "whooping" sound is present, obtain nasopharyngeal swab and start macrolides (azithromycin or clarithromycin) immediately 3, 4