What is the recommended workup and treatment for a patient with chronic cough, considering potential underlying causes such as respiratory infections, gastroesophageal reflux disease (GERD), or asthma?

Chronic Cough Workup and Management

Initial Evaluation

Begin by obtaining a chest radiograph to exclude serious pathology including malignancy, infection, and structural abnormalities, and immediately discontinue any ACE inhibitor if the patient is taking one, as this medication class commonly causes chronic cough that resolves within 1-4 weeks of cessation. 1, 2

Critical First Steps

• Check medication list specifically for ACE inhibitors and switch to an alternative antihypertensive class if present 1, 2
• Obtain chest X-ray to rule out pneumonia, pulmonary embolism, bronchogenic carcinoma, tuberculosis, and structural lung disease 1, 3, 2
• Assess smoking status and strongly advise cessation, as this alone can resolve cough within 4 weeks 1, 4
• Evaluate for environmental/occupational irritant exposures that may be perpetuating the cough 4

Key History Elements to Elicit

• Duration of cough: Postinfectious cough lasts 3-8 weeks; chronic cough exceeds 8 weeks 5, 6
• Presence of wheezing or dyspnea suggesting asthma 1
• Nasal congestion, postnasal drip, or sinus symptoms indicating upper airway cough syndrome 1, 6
• Heartburn, regurgitation, or epigastric pain suggesting GERD 5, 6
• Recent travel to Japan, Korea, or China where diffuse panbronchiolitis should be considered 5
• Recent respiratory infection within the past 8 weeks suggesting postinfectious cough 5

Algorithmic Treatment Approach

Step 1: Treat Most Likely Cause Based on Clinical Features

For patients with wheezing or dyspnea, initiate inhaled corticosteroids combined with long-acting β-agonists (such as fluticasone/salmeterol twice daily) and monitor for response within 2-4 weeks. 1

For patients with nasal congestion or postnasal drip symptoms, start a first-generation antihistamine/decongestant combination with expected improvement within 1-2 weeks. 1, 2

For patients with heartburn or regurgitation, initiate proton pump inhibitor therapy taken 30-60 minutes before meals, but only when clear GI symptoms are present—never for isolated cough alone. 5, 7

Step 2: Sequential Addition if Incomplete Response

• If asthma treatment yields incomplete response, add antihistamine/decongestant for upper airway cough syndrome while continuing the initial therapy, as cough is often multifactorial 1
• If still inadequate response after addressing asthma and upper airway, then add empiric GERD treatment with PPI therapy 1
• Continue all effective therapies simultaneously rather than stopping previous treatments, as multiple conditions frequently coexist 1, 4

Step 3: Consider Less Common Etiologies

For postinfectious cough (3-8 weeks post-viral illness), try inhaled ipratropium first; if this fails and cough significantly impairs quality of life, consider inhaled corticosteroids or a short course of oral prednisone 30-40 mg daily after ruling out other common causes. 5

For suspected pertussis (paroxysmal cough with post-tussive vomiting or inspiratory whoop lasting ≥2 weeks), obtain nasopharyngeal culture for definitive diagnosis. 5

Critical Pitfalls to Avoid

GERD Treatment Misuse

Do not prescribe acid suppressive therapy for isolated chronic cough without gastrointestinal symptoms—this is a Grade 1B/1C recommendation against this practice. 5, 7, 8

• Acid suppression should only be used when clear GI features are present: heartburn, epigastric pain, or regurgitation 5
• In children, do not treat for GERD without recurrent regurgitation, dystonic neck posturing (infants), or heartburn/epigastric pain (older children) 5
• PPIs carry significant risks with long-term use (≥1 year) including fractures, C. difficile infection, and vitamin B12 deficiency 7

Antibiotic Misuse

Do not prescribe antibiotics for postinfectious cough, as the cause is not bacterial infection and antibiotics provide no benefit. 5

Duration of Empiric Trials

• Allow 2-4 weeks for asthma therapy response 1
• Allow 1-2 weeks for upper airway cough syndrome therapy response 1
• Allow 4-8 weeks for GERD therapy response before reassessment 5, 7

Advanced Workup When Initial Management Fails

If cough persists despite sequential trials addressing the three most common causes (upper airway cough syndrome, asthma, GERD), obtain pulmonary function testing with spirometry and consider bronchoprovocation challenge to confirm or exclude asthma. 1, 3, 2

• High-resolution CT chest may be indicated if chest X-ray is normal but suspicion remains for structural disease 9, 2
• Consider induced sputum for eosinophils to evaluate for non-asthmatic eosinophilic bronchitis 1
• Referral to pulmonology is appropriate when diagnosis remains unclear after systematic evaluation 1, 9

Refractory Chronic Cough Management

For patients with refractory chronic cough after negative workup for life-threatening causes and failed trials of common treatments, consider cough hypersensitivity syndrome and initiate gabapentin or pregabalin along with speech pathology therapy. 5, 9

• Central antitussives (codeine, dextromethorphan) can be considered when other measures fail 5
• For patients with interstitial lung disease and refractory cough severely affecting quality of life, opiates may be used in a palliative care setting with reassessment at 1 week and monthly thereafter 5