What is the appropriate evaluation and treatment approach for a patient presenting with a chronic cough, potentially complicated by smoking history and possible underlying conditions such as lung disease or GERD?

Chronic Cough: Evaluation and Treatment

Immediate First Steps

If the patient is taking an ACE inhibitor, discontinue it immediately regardless of when the cough started—resolution typically occurs within days to 2 weeks, though median time is 26 days. 1

If the patient is a current smoker, smoking cessation is the absolute priority intervention, as most patients achieve cough resolution within 4 weeks of cessation. 1

Initial Clinical Assessment

Focus your history and physical examination on these specific elements:

• Duration of cough (chronic cough is defined as >8 weeks in adults) 2
• Red flag symptoms requiring immediate investigation rather than empiric treatment: hemoptysis, significant dyspnea, fever or systemic symptoms, weight loss, history of cancer, tuberculosis, or AIDS 1
• Medication history (particularly ACE inhibitors) 1
• Smoking status and pack-year history (>10 pack-years significantly alters differential) 2
• Symptoms suggesting the "big three" causes: nasal congestion/postnasal drip (UACS), wheezing/dyspnea (asthma), heartburn/regurgitation (GERD) 3

Obtain a chest radiograph in most patients during initial evaluation 2, 4. However, recognize that chest radiography misses up to 34% of CT-proven bronchiectasis cases and up to 42% of patients with presumed normal chest radiographs have abnormalities on HRCT 1.

The Sequential Empiric Treatment Approach

The evidence strongly supports treating empirically rather than extensive upfront testing, as this approach is more cost-effective when UACS prevalence is approximately 44%. 1 The American Thoracic Society advises against ordering extensive testing upfront 1.

Treatment Algorithm Based on Clinical Presentation:

For patients with nasal congestion or postnasal drip symptoms (UACS):

• Initiate a first-generation antihistamine/decongestant combination 3
• Expected improvement within 1-2 weeks 3
• UACS accounts for the majority of chronic cough cases in immunocompetent nonsmokers 1

For patients with wheezing or dyspnea (suspected asthma):

• Initiate inhaled corticosteroids combined with long-acting β-agonists 3
• Monitor for response within 2-4 weeks 3
• The British Thoracic Society recommends initiating inhaled corticosteroids with or without bronchodilators even without spirometric evidence of obstruction, as many patients with cough-variant asthma lack sufficient reversibility to meet traditional asthma criteria 1

For patients with heartburn or regurgitation (GERD):

• Initiate proton pump inhibitor therapy taken 30-60 minutes before meals, but only when clear GI symptoms are present 3
• Allow 4-8 weeks for GERD therapy response before reassessment 3
• The American Gastroenterological Association notes that GERD is frequently overlooked as an extrapulmonary cause and recommends intensive acid suppression therapy for at least 3 months 1
• Critical caveat: Acid suppression should only be used when clear GI features are present (heartburn, epigastric pain, or regurgitation)—do not use empirically for isolated cough 3

When to Pursue Advanced Imaging

Proceed to high-resolution CT (HRCT) only after sequential empiric treatment for all three common causes has failed, and adequate treatment duration has been allowed (several weeks for UACS/asthma, ≥3 months for GERD). 1

HRCT is the reference standard for detecting bronchiectasis, which accounts for up to 8% of chronic cough cases and may be missed on chest radiography 1. The British Thoracic Society notes that HRCT identifies abnormalities in up to 42% of patients with presumed normal chest radiographs, and is diagnostic in 24% of patients with chronic cough who had normal radiographs and failed initial protocols 1.

Special Considerations

Postinfectious cough (lasting 3-8 weeks):

• Try inhaled ipratropium first 3
• If this fails, consider inhaled corticosteroids or a short course of oral prednisone 30-40 mg daily after ruling out other common causes 3

Multiple causes are common:

• Up to one-fourth of patients have multiple disorders contributing to cough 5
• If initial treatment for one condition partially improves but doesn't resolve cough, sequentially add treatment for the next most likely cause 2

Management of Refractory Chronic Cough

If cough persists despite sequential trials addressing the three most common causes:

• Obtain pulmonary function testing with spirometry and consider bronchoprovocation challenge to confirm or exclude asthma 3
• Consider cough hypersensitivity syndrome 3
• Initiate gabapentin or pregabalin along with speech pathology therapy 3
• Low-dose morphine is preferred among neuromodulatory agents 6

Common Pitfalls to Avoid

• Do not rely on chest radiography alone to exclude bronchiectasis—up to 34% of CT-proven cases have normal chest radiographs 1
• Do not use acid suppression for isolated cough without GI symptoms—this is the most common error and lacks evidence for efficacy 3, 7
• Do not order extensive testing upfront—sequential empiric treatment is more cost-effective than comprehensive initial investigation 1
• Do not forget that significant smoking (>10 pack-years) was an exclusion criterion in most chronic cough trials—active smokers need cessation first 2