What is the appropriate evaluation and management for an adult patient presenting with chronic cough?

Evaluation and Management of Adult Chronic Cough

A systematic algorithmic approach combining targeted diagnostic testing with sequential empiric treatment trials is the most effective strategy for managing chronic cough, addressing the three most common causes: upper airway cough syndrome (UACS), asthma, and gastroesophageal reflux disease (GERD), which account for the vast majority of cases. 1, 2

Initial Mandatory Assessment

Baseline Investigations

• Obtain chest radiograph in all patients to exclude malignancy, infection, or structural abnormalities 1, 2
• Perform spirometry with bronchodilator response to identify airflow obstruction and assess reversibility 1, 2
• Immediately discontinue ACE inhibitors if present—no patient with troublesome cough should continue these medications 3, 2
• Mandate smoking cessation for all smokers, as this alone can lead to significant symptom remission 2

Focused History Elements

• Identify cobblestoning of posterior pharyngeal wall, constant throat clearing, and seasonal patterns suggesting UACS 3
• Assess for reflux symptoms, recognizing that reflux-associated cough may occur without any gastrointestinal symptoms—failure to consider GERD is a common reason for treatment failure 4, 3
• Document occupational exposures and environmental triggers 1
• Quantify cough severity using validated cough-specific quality of life questionnaires or visual analog scales 3, 2

Critical Recognition

• Approximately 20% of UACS cases present "silently" without typical nasal discharge, and poor correlation exists between upper airway symptom severity and cough presence 3
• Chronic cough is frequently multifactorial—patients commonly have two or all three common diagnoses simultaneously, and cough will not resolve until all contributing factors are treated 1

Sequential Treatment Algorithm

First-Line: Upper Airway Cough Syndrome

• Initiate intranasal corticosteroids (fluticasone propionate 100-200 mcg daily) as first-line therapy, effective in both allergic and non-allergic rhinitis-related cough 3
• Trial topical corticosteroid for minimum 1 month when prominent upper airway symptoms are present 4, 3
• Add ipratropium bromide nasal spray for anticholinergic drying effects, particularly useful with contraindications to oral decongestants 3
• Perform ear, nose, and throat examination in preference to sinus imaging for suspected rhinosinusitis 4, 3

Second-Line: Asthma/Eosinophilic Airway Disease

• Perform bronchial provocation testing (methacholine challenge) in patients with normal spirometry—a negative test excludes asthma but does not rule out steroid-responsive cough 4, 1
• If methacholine testing unavailable, use a 2-week trial of oral corticosteroids to diagnose eosinophilic airway inflammation; lack of response effectively rules it out 1
• Initiate inhaled corticosteroids with bronchodilators if asthma confirmed 1

Third-Line: Gastroesophageal Reflux Disease

• Initiate intensive acid suppression with proton pump inhibitors (omeprazole 20-40 mg twice daily) plus alginates for minimum 3 months—this is non-negotiable, as shorter durations are inadequate 4, 3, 2
• Empirical treatment should be offered before oesophageal testing, as no current test of oesophageal function predicts treatment response 4
• Include dietary modifications: low-fat diet, avoid coffee, tea, chocolate, citrus, and alcohol 3

Monitoring and Follow-Up

• Schedule follow-up in 4-6 weeks to assess response using validated instruments 3
• Address causes sequentially and additively—do not stop after first intervention, as multiple causes frequently coexist 2
• Monitor blood pressure closely given potential need for decongestants 3

Advanced Investigations (When Initial Approach Fails)

Indications for Further Testing

• Red flag symptoms: fever, weight loss, hemoptysis, or recurrent pneumonia warrant chest CT 5, 6
• Immunocompromised patients or those from tuberculosis-endemic areas require additional workup 1
• Persistent symptoms despite adequate treatment trials (1 month for UACS, 3 months for GERD) 3, 2

Specialized Testing

• High-resolution CT chest to evaluate for bronchiectasis, interstitial lung disease, or occult malignancy 1, 2
• Fibreoptic laryngoscopy for persistent upper airway symptoms despite adequate treatment trial 4, 3
• Induced sputum for eosinophilia assessment after exclusion of other common causes—demonstration of sputum eosinophilia has important treatment implications 4
• Bronchoscopy if foreign body inhalation suspected or structural abnormalities possible 2

Refractory Chronic Cough

• Chronic cough should only be considered idiopathic following thorough assessment at a specialist cough clinic—premature diagnosis of idiopathic cough is a critical pitfall 4, 3, 2
• Referral to specialist cough clinic is strongly encouraged for unexplained chronic cough after complete evaluation and adequate treatment duration 4, 2
• For refractory cases, consider neuromodulatory treatment with low-dose morphine (preferred), gabapentin, or pregabalin 7, 6
• Speech and language therapy combined with pharmacologic treatment may be beneficial 5, 8

Critical Pitfalls to Avoid

• Never undertreat GERD: requires full 3-month trial of intensive acid suppression, not shorter durations 3, 2
• Never continue ACE inhibitors in patients with troublesome cough 2
• Ensure adequate treatment duration before declaring treatment failure: topical corticosteroids require 1 month minimum, GERD treatment requires 3 months minimum 3
• Recognize that cough suppression may be contraindicated when cough clearance is important for secretion management 4, 2
• Avoid relying solely on spirometry to diagnose asthma, as cough-variant asthma may present with normal spirometry 1
• Do not overlook multiple simultaneous causes—use additive sequential therapy rather than stopping after the first intervention 2
• Absence of prominent upper airway symptoms does not exclude UACS 3