What is the recommended evaluation and management of cough in an adult?

Management of Cough in Adults

The management of cough depends critically on duration: acute cough (<3 weeks) is typically viral and self-limiting requiring only symptomatic treatment, while chronic cough (>8 weeks) demands systematic evaluation with mandatory chest radiography and spirometry, followed by targeted treatment of the most common causes—upper airway cough syndrome, asthma/eosinophilic bronchitis, and gastroesophageal reflux disease. 1

Initial Classification by Duration

The first step is determining cough duration, as this fundamentally changes your approach:

• Acute cough: <3 weeks duration
• Post-viral cough: 3-8 weeks duration
• Chronic cough: >8 weeks duration 1

Acute Cough Management (<3 Weeks)

Key Clinical Features

Acute cough is most commonly caused by viral upper respiratory tract infection and is benign and self-limiting in the absence of significant comorbidity 1.

Red Flags Requiring Further Investigation

Proceed with additional workup if any of the following are present:

• Hemoptysis
• Prominent systemic illness
• Suspicion of inhaled foreign body
• Suspicion of lung cancer 1

Treatment Approach

For uncomplicated acute viral cough, prescribed treatment is unnecessary, but patients report benefit from over-the-counter preparations despite little evidence of specific pharmacological effect 1. The simplest advice is home remedies like honey and lemon 1.

If symptomatic treatment is desired, evidence supports:

• Dextromethorphan: 60 mg for maximum cough reflex suppression (higher than typical OTC dosing) 1
• Menthol inhalation: Provides acute but short-lived suppression 1
• Sedative antihistamines: May be suitable for nocturnal cough 1

Avoid codeine or pholcodine—they have no greater efficacy than dextromethorphan but significantly more adverse effects 1.

Chronic Cough Evaluation (>8 Weeks)

Epidemiology and Impact

Chronic cough affects 10-20% of adults, is more common in females and obese individuals, and causes quality of life impairment comparable to severe COPD 1.

Mandatory Initial Evaluation

Every patient with chronic cough must receive:

1. Detailed history including:

   • Smoking status (dose-related cause of persistent cough) 1
   • Current medications, specifically ACE inhibitors 1
   • Occupational and environmental exposures 1
   • Symptoms suggesting upper airway disease, reflux, or asthma

2. Physical examination focusing on:

   • Upper airway (nasal congestion, post-nasal drainage)
   • Chest auscultation for wheezing or crackles
   • Signs of reflux disease

3. Chest radiography (mandatory) 1

4. Spirometry (mandatory) 1

5. Assessment of cough severity using validated quality of life questionnaires or visual analogue scores 1

Additional Testing When Indicated

Bronchial provocation testing: Perform in patients without clinically obvious etiology who have normal spirometry 1

Induced sputum for eosinophilia: Request after excluding other common causes, as sputum eosinophilia has important treatment implications 1

High-resolution CT: Consider when other targeted investigations are normal 1

Bronchoscopy: Undertake when foreign body inhalation is suspected 1

Chronic Cough Treatment Algorithm

Step 1: Address High-Risk Factors

ACE Inhibitors: No patient with troublesome cough should continue on ACE inhibitors—discontinue immediately 1

Smoking: Encourage cessation as it is accompanied by significant remission in cough symptoms 1

Step 2: Empiric Treatment for Common Causes

The most common aggravants are asthma/eosinophilic bronchitis, gastroesophageal reflux disease, and upper airway cough syndrome 1.

Asthma/Eosinophilic Bronchitis

• No currently available tests can reliably exclude corticosteroid-responsive cough 1
• Trial of oral corticosteroids for 2 weeks: If no response, cough is unlikely due to eosinophilic airway inflammation 1
• Inhaled corticosteroids: Follow national asthma guidelines for dosing and duration 1
• Leukotriene receptor antagonists: Evidence exists for use at step 3 of asthma management 1
• Avoid long-acting β-agonists at step 3 for cough variant asthma—insufficient evidence 1

Gastroesophageal Reflux Disease

Reflux-associated cough may occur without gastrointestinal symptoms—failure to consider GORD is a common reason for treatment failure 1.

Treatment protocol:

• Proton pump inhibitors: 20-40 mg omeprazole (or equivalent) twice daily before meals for minimum 8 weeks (some sources say 2-3 months) 1
• Prokinetic agents: Metoclopramide 10 mg three times daily may be required in some patients 1
• Antireflux surgery: May be effective in carefully selected cases after comprehensive evaluation including 24-hour pH monitoring, manometry, and failed PPI trial 1

Upper Airway Cough Syndrome (Post-Nasal Drip)

Rhinosinusitis is commonly associated with chronic cough, though symptoms correlate poorly with cough presence 1.

Treatment approach:

• Intranasal corticosteroids: 1-month trial in presence of prominent upper airway symptoms 1
• Antihistamines: Evidence is conflicting; first-generation sedating antihistamines may be more effective but are not universally available 1

Step 3: Quantify Treatment Response

Treatment effects must be formally quantified using validated cough severity measures 1. This is an audit standard.

Step 4: Refractory Chronic Cough

When diagnostic tests and specific directed treatments fail to control cough despite adequate trials (typically 4-6 weeks of empiric treatment), consider:

Neuromodulatory therapy:

• Low-dose morphine: Highly effective in subset of patients with cough resistant to other treatments 2
• Gabapentin or pregabalin: Advocated but limited by adverse events in clinical practice 2, 3, 4, 5

Cough suppression therapy: When performed by competent practitioners (speech and language therapy/physiotherapy), can be highly effective 2, 3, 4

Common Pitfalls to Avoid

1. Inadequate treatment duration: PPIs must be given for minimum 2-3 months, not the typical 4-6 weeks used for dyspepsia 1

2. Failing to discontinue ACE inhibitors: This is a mandatory step before pursuing extensive workup 1

3. Not quantifying treatment response: Use validated tools to objectively assess whether interventions are working 1

4. Assuming single etiology: Multiple causes may coexist; systematic evaluation of all common causes is necessary 1

5. Premature diagnosis of refractory cough: Ensure adequate trials of corticosteroids (2 weeks oral), PPIs (8+ weeks), and upper airway treatment (1 month) before declaring cough refractory 1

6. Overlooking cough hypersensitivity: In truly refractory cases, the underlying mechanism is vagal afferent hypersensitivity requiring neuromodulation rather than continued pursuit of elusive "causes" 2