What is the appropriate management for a patient with a persistent cough?

Management of Persistent Cough

Begin by classifying the cough duration as acute (<3 weeks), subacute (3-8 weeks), or chronic (>8 weeks), as this determines your entire diagnostic and therapeutic approach. 1

Immediate Actions

• Stop ACE inhibitors immediately if the patient is taking one—this is a common reversible cause with resolution typically within days to 2 weeks (median 26 days). 1, 2
• Counsel smokers on cessation urgently, as 90-94% achieve cough resolution within the first year of quitting. 1, 2
• Rule out life-threatening conditions first: assess for pneumonia, pulmonary embolism, or systemic illness by evaluating respiratory distress indicators including markedly elevated respiratory rate, intercostal retractions, cyanosis, or altered mental status. 1, 2

Essential Baseline Investigations

• Obtain a chest radiograph in all patients with chronic cough and those with acute cough showing atypical symptoms (fever, tachypnea, tachycardia, dyspnea, abnormal lung findings). 3, 1, 2, 4
• Perform spirometry in all patients with chronic cough to identify obstructive patterns and assess reversibility. 3, 1, 2

Note: 31% of chest X-rays ordered for persistent cough reveal abnormalities or yield a diagnosis, making this a high-yield test. 4 However, the negative predictive value is only 64%, so a normal X-ray does not exclude pulmonary causes. 4

Management Based on Duration

Acute Cough (<3 weeks)

• For common cold: Use a first-generation antihistamine/decongestant combination plus naproxen. 1
• Do not use newer non-sedating antihistamines—they are ineffective for cough. 2
• For acute exacerbation of chronic bronchitis: Consider a short course of systemic corticosteroids. 1

Subacute Cough (3-8 weeks)

• Determine if postinfectious or non-infectious. 1, 2
• For postinfectious cough: Consider inhaled ipratropium as first-line therapy. 3
• If cough persists despite ipratropium: Add inhaled corticosteroids. 3
• For severe paroxysms: Consider prednisone 30-40 mg daily for a short, finite period after ruling out other common causes. 3
• Consider pertussis if cough lasts ≥2 weeks with paroxysms, post-tussive vomiting, or inspiratory whooping sound. 3

Chronic Cough (>8 weeks)

Use a sequential and additive treatment approach targeting the three most common causes, which frequently coexist. 3, 1, 2

Sequential Empiric Treatment for Chronic Cough

Step 1: Upper Airway Cough Syndrome (UACS)

• Start with an oral first-generation antihistamine/decongestant combination. 3, 1, 2
• Add a topical nasal corticosteroid if prominent upper airway symptoms are present. 1, 2
• UACS accounts for approximately 44% of chronic cough cases. 4

Step 2: Asthma

• If spirometry shows reversible airflow obstruction: Treat with inhaled bronchodilators and inhaled corticosteroids. 1, 2
• If spirometry is normal but asthma is suspected: Perform bronchoprovocation challenge ideally, or proceed with empiric trial of inhaled corticosteroids and bronchodilators. 3, 1, 2
• Consider a limited trial of oral corticosteroids before eliminating asthma from consideration. 3

Critical pitfall: Many patients with cough-predominant asthma do not have spirometric reversibility or obstruction, so normal spirometry does not exclude asthma. 3

Step 3: Non-Asthmatic Eosinophilic Bronchitis (NAEB)

• Perform induced sputum test for eosinophils if available. 3, 1, 2
• If testing unavailable: Use empiric treatment with inhaled corticosteroids. 3, 1, 2

Step 4: Gastroesophageal Reflux Disease (GERD)

• Initiate empiric treatment for patients with typical reflux symptoms before performing esophageal testing. 1, 2
• Use intensive acid suppression with proton pump inhibitors for a minimum of 2 months. 2

When Initial Treatment Fails

• If cough persists after 4-6 weeks of empiric treatment for the top diagnoses: Pursue advanced testing including high-resolution CT scan or bronchoscopic evaluation for uncommon causes. 3, 1, 2
• Consider referral to a specialist cough clinic when diagnosis remains unclear. 3, 1, 2
• Bronchoscopy should be undertaken in all patients in whom inhalation of a foreign body is suspected. 3, 2

Critical Pitfalls to Avoid

• Do not rely on cough characteristics alone (timing, quality, sound)—they have little diagnostic value. 3, 1, 2
• Do not treat only one cause—multiple factors often contribute simultaneously, requiring additive therapy. 3, 1, 2
• Do not label as idiopathic until thorough assessment at a specialist clinic excludes uncommon causes. 3, 1, 2
• Do not use single peak expiratory flow (PEF) measurements for assessing bronchodilator response—they are not as accurate as FEV1. 3, 2

Special Populations

Immunocompromised Patients

• Use the same initial algorithm but expand the differential diagnosis based on immune defect type and severity. 3, 1
• In HIV patients with CD4+ <200 cells/μL: Suspect Pneumocystis pneumonia, tuberculosis, and opportunistic infections. 3, 1