What is the best course of treatment for a patient with a chronic cough?

Chronic Cough Treatment

For adults with chronic cough (lasting >8 weeks), begin with a systematic algorithmic approach targeting the three most common causes sequentially: start with inhaled corticosteroids plus bronchodilators for asthma, add first-generation antihistamine/decongestant for upper airway cough syndrome if incomplete response, then add proton pump inhibitor therapy for gastroesophageal reflux disease if cough persists. 1

Initial Critical Steps

Before initiating treatment trials, complete these mandatory actions:

• Discontinue ACE inhibitors immediately if the patient is taking one, as this is a common reversible cause; cough may take 1-4 weeks to resolve after discontinuation 2, 1
• Counsel and assist with smoking cessation as smoking-related cough can resolve within 4 weeks of quitting 2, 1
• Obtain chest radiograph in all patients to exclude serious pathology such as malignancy, tuberculosis, or bronchiectasis 2
• Perform spirometry to identify airflow obstruction and assess bronchodilator response 2

Sequential Treatment Algorithm

Step 1: Treat Asthma/Eosinophilic Airway Disease (First-Line)

Initiate inhaled corticosteroids combined with long-acting β-agonists (e.g., fluticasone/salmeterol twice daily) as the initial empiric therapy 2, 1. This addresses both cough-variant asthma and non-asthmatic eosinophilic bronchitis, which together represent the most common causes of chronic cough. 2

• Monitor for response within 2-4 weeks 1
• If spirometry shows normal baseline values, consider bronchial provocation testing to confirm asthma, though a negative test does not exclude steroid-responsive cough 2
• For refractory cases after 2-4 weeks, add a leukotriene receptor antagonist before escalating to systemic corticosteroids 2
• For severe/refractory cough, prescribe a short course (1-2 weeks) of oral prednisolone followed by continued inhaled corticosteroids 2

Step 2: Add Treatment for Upper Airway Cough Syndrome (If Incomplete Response)

Add a first-generation antihistamine/decongestant combination if cough persists or only partially improves after asthma treatment 1, 3. Upper airway cough syndrome (previously called postnasal drip syndrome) frequently coexists with other causes. 2

• Expect some improvement within 1-2 weeks, though complete resolution may take several weeks 1
• First-generation antihistamines are essential; newer non-sedating antihistamines are ineffective for cough 3
• Consider topical nasal corticosteroids if prominent upper airway symptoms are present 2

Step 3: Add GERD Treatment (If Still Inadequate Response)

Initiate intensive acid suppression with proton pump inhibitors if cough persists despite treatment for asthma and upper airway disease 2, 1. GERD-related cough often occurs without typical heartburn or regurgitation symptoms. 2

• Continue previous treatments as chronic cough is frequently multifactorial 1, 3
• Prescribe intensive therapy for minimum 3 months: proton pump inhibitor twice daily, dietary modifications (limit fat to <45g/day, avoid coffee, tea, alcohol, chocolate, citrus, tomatoes), and consider adding prokinetic agent 2
• Response may be delayed; assess after 1-3 months of therapy 2
• If empiric therapy fails, 24-hour esophageal pH monitoring is the most sensitive test, though normal results do not exclude GERD as the cause 2

Special Diagnostic Considerations

When Standard Algorithm Fails

If cough persists after sequential trials of all three treatments:

• Consider non-asthmatic eosinophilic bronchitis by checking induced sputum or bronchial wash for eosinophilia; treat with inhaled corticosteroids if confirmed 2
• Perform bronchoscopy if foreign body aspiration is suspected or if other targeted investigations remain normal 2
• Consider high-resolution CT scan when chest radiograph is normal but clinical suspicion remains for bronchiectasis or interstitial lung disease 2

Red Flags Requiring Immediate Further Investigation

Obtain advanced imaging and specialist referral if any of these are present:

• Hemoptysis
• Unintentional weight loss
• Fever lasting >1 week
• Recurrent pneumonia
• Abnormal chest radiograph 4, 5

Refractory Chronic Cough Management

For patients who remain symptomatic despite optimal treatment of identified causes:

• Consider cough hypersensitivity syndrome as the underlying mechanism 4, 6
• Prescribe low-dose morphine (preferred), gabapentin, or pregabalin for symptomatic management 4, 6
• Refer for speech and language therapy/physiotherapy focused on cough control techniques 5

Critical Pitfalls to Avoid

• Never assume a single cause: chronic cough is multifactorial in the majority of cases; continue all effective treatments rather than stopping one when adding another 1, 3
• Do not use expectorants: there is no evidence that guaifenesin or other expectorants are effective for chronic cough 2
• Avoid treating only one potential cause: approximately 62% of patients have multiple contributing factors 7
• Do not assume GERD is excluded by normal endoscopy or by history of antireflux surgery 2
• Never use newer non-sedating antihistamines for upper airway cough syndrome; only first-generation antihistamines are effective 3

Treatment Duration and Monitoring

• Assess response to each treatment step at 2-4 weeks for asthma therapy 1
• Allow 1-2 weeks for upper airway treatment response 1
• Continue GERD therapy for minimum 3 months before declaring treatment failure 2
• Use validated cough severity and quality of life instruments to objectively measure treatment response 6