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

Chronic Cough: Treatment Approach

For chronic cough (lasting >8 weeks), begin with a systematic algorithmic approach targeting the three most common causes sequentially: upper airway cough syndrome (UACS), asthma, and gastroesophageal reflux disease (GERD), as these account for the vast majority of cases and often coexist. 1, 2

Initial Critical Steps

Before initiating any treatment algorithm, address these mandatory interventions:

• 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 1, 2, 3
• Strongly counsel smoking cessation as smoking-related cough can resolve within 4 weeks of quitting 1, 2, 3
• Obtain chest radiograph to exclude serious pathology (malignancy, tuberculosis, bronchiectasis) before proceeding with empiric treatment 1, 2
• Perform spirometry to identify airflow obstruction and assess bronchodilator reversibility 1

Sequential Treatment Algorithm

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

Initiate inhaled corticosteroids (ICS) combined with long-acting β-agonists (LABA) such as fluticasone/salmeterol twice daily, even if spirometry is normal, as cough-variant asthma may not show airflow obstruction 1, 2

• Assess response within 2-4 weeks 2
• If spirometry shows reversible obstruction, this confirms asthma as the diagnosis 1
• For refractory cases after 2-4 weeks, add a short course (1-2 weeks) of oral corticosteroids (e.g., prednisone) followed by continuation of ICS 1
• Consider adding leukotriene receptor antagonist before escalating to systemic steroids if initial ICS/LABA combination fails 1

Critical caveat: A negative bronchoprovocation test excludes asthma but does NOT rule out non-asthmatic eosinophilic bronchitis (NAEB), which also responds to corticosteroids 1, 2

Step 2: Add Treatment for Upper Airway Cough Syndrome (UACS)

If incomplete response to asthma treatment after 2-4 weeks:

• Add first-generation antihistamine/decongestant combination (e.g., chlorpheniramine with pseudoephedrine) 1, 2, 3
• Newer non-sedating antihistamines are ineffective for cough and should NOT be used 3
• Expect some improvement within 1-2 weeks, though complete resolution may take several weeks 2
• If prominent upper airway symptoms exist, add intranasal corticosteroid 1, 2

Important pitfall: Do not discontinue asthma treatment when adding UACS therapy, as chronic cough is frequently multifactorial 2, 3

Step 3: Add Treatment for GERD

If cough persists despite Steps 1 and 2:

• Initiate proton pump inhibitor (PPI) therapy with intensive dietary modifications for a minimum of 3 months 1, 2
• Dietary restrictions: limit fat to <45g/24 hours, eliminate coffee, tea, soda, chocolate, mints, citrus (including tomatoes), and alcohol 1
• Add prokinetic agent (e.g., metoclopramide) if PPI alone is insufficient after 4-6 weeks 1
• Continue all previous treatments as cough is often multifactorial 1, 2

Critical caveat: GERD-related cough frequently occurs WITHOUT gastrointestinal symptoms, so absence of heartburn does not exclude this diagnosis 1

When Initial Algorithm Fails

If cough persists after 3 months of sequential treatment:

• Consider bronchoprovocation challenge testing if not already performed to confirm or exclude asthma 1, 2
• Assess for non-asthmatic eosinophilic bronchitis (NAEB) via induced sputum or bronchoscopy for eosinophils; treat with ICS if confirmed 1, 2
• Perform 24-hour esophageal pH monitoring to objectively confirm GERD and assess adequacy of acid suppression 1
• Consider high-resolution CT scan if chest radiograph was normal but symptoms persist 1

Refractory Chronic Cough Management

For patients failing all specific treatments after 4-6 months:

• Low-dose morphine is the preferred neuromodulator for symptomatic relief 4
• Gabapentin or pregabalin can be used as alternatives 5, 4, 6
• Speech and language therapy/cough suppression therapy should be offered concurrently 5, 6

Do NOT use: Codeine or dextromethorphan are only recommended for short-term symptomatic relief in chronic bronchitis, not for chronic cough of other etiologies 1

Common Pitfalls to Avoid

• Never treat only one potential cause – approximately 60% of chronic cough cases have multiple contributing factors 3, 7
• Do not use albuterol/salbutamol alone for chronic cough without confirmed asthma; it is ineffective and delays proper diagnosis 8
• Do not assume GERD is excluded by normal endoscopy or lack of GI symptoms 1
• Do not use guaifenesin (expectorant) – there is no evidence it is effective for chronic cough 1, 9
• Do not perform extensive testing before empiric treatment trials – this is not cost-effective 1, 4

Red Flags Requiring Immediate Further Investigation

Refer urgently or obtain advanced imaging (CT chest) if any of the following are present:

• Hemoptysis 5, 6
• Unintentional weight loss 5, 6
• Fever with cough >3 weeks 3, 5
• Recurrent pneumonia 5
• Abnormal chest radiograph 1
• Dysphagia or hoarseness 6