What should I do for a 2-week persistent cough, especially at night, with no significant medical history?

Management of 2-Week Persistent Nighttime Cough

For a 2-week cough that worsens at night with no significant medical history, you should immediately consider pertussis infection and initiate azithromycin 500 mg daily for 3-5 days if paroxysmal coughing, post-tussive vomiting, or inspiratory whooping is present, while simultaneously isolating the patient for 5 days from treatment start. 1, 2

Immediate Diagnostic Priorities

Rule Out Pertussis First

• Any cough lasting ≥2 weeks with paroxysmal episodes should be considered pertussis until proven otherwise. 1, 2, 3
• Look specifically for: paroxysmal coughing fits, post-tussive vomiting, or inspiratory whooping sound. 4, 1, 2
• Obtain nasopharyngeal aspirate or Dacron swab for culture confirmation, but do not delay treatment while waiting for laboratory results—early treatment within the first 2 weeks decreases paroxysms and prevents transmission. 4, 1, 3
• If pertussis is diagnosed or strongly suspected, isolate the patient for 5 days from antibiotic initiation to prevent transmission. 1, 2

Assess for Red Flags Requiring Urgent Evaluation

• Hemoptysis, constitutional symptoms (fever, weight loss), respiratory distress, or hypoxemia mandate immediate chest radiography and further workup. 1, 2, 3
• Tachypnea (≥24 breaths/min), tachycardia (≥100 bpm), fever (≥38°C), or focal lung findings suggest pneumonia requiring immediate evaluation. 3
• Asymmetrical lung sounds or focal consolidation warrant chest radiography to exclude pneumonia, lung cancer, or bronchiectasis. 3

Treatment Algorithm Based on Clinical Presentation

If Pertussis is Suspected or Confirmed

• Start azithromycin 500 mg once daily for 3-5 days immediately—this is the preferred first-line treatment. 1, 2
• Implement isolation precautions for 5 days from treatment start. 1, 2
• Early treatment diminishes coughing paroxysms and prevents disease transmission. 1, 3

If Post-Viral/Post-Infectious Cough is More Likely

At 2 weeks, this cough is still classified as acute (acute cough is defined as <3 weeks duration). 4, 2 Most viral upper respiratory infection-associated coughs resolve within 2 weeks, so persistence raises concern for evolving post-viral cough. 2

Symptomatic management options:

• Ipratropium inhalation is first-line for cough suppression in post-viral cough. 4, 1, 2
• Dextromethorphan 60 mg (not over-the-counter subtherapeutic doses) is recommended when other measures fail. 4, 1, 2
• For severe paroxysms adversely affecting quality of life, consider prednisone 30-40 mg/day for a short, finite period (2-3 weeks with taper) after ruling out other common causes. 4, 1

Critical pitfall: Do not prescribe antibiotics for viral post-infectious cough—they provide no benefit, contribute to antibiotic resistance, and cause adverse effects. 4, 1, 2, 3

Nighttime Cough Considerations

The nighttime predominance suggests several possibilities:

• Cough-variant asthma typically worsens at night or after exposure to cold or exercise. 4
• Upper airway cough syndrome (postnasal drip) from persistent nasal/sinus inflammation can worsen when supine. 3
• Gastroesophageal reflux disease can be triggered or worsened by recumbent position. 3

However, at 2 weeks duration, these diagnoses are premature—they become relevant if cough persists beyond 3-8 weeks. 4, 3

Timeline for Reassessment and Escalation

At 3 Weeks (Subacute Cough Threshold)

• If cough persists into the 3-8 week window, it becomes classified as subacute postinfectious cough. 4, 3
• This results from postviral airway inflammation, bronchial hyperresponsiveness, mucus hypersecretion, and impaired mucociliary clearance. 3
• Most patients experience resolution within this timeframe (average 26 days). 3
• Continue ipratropium inhalation as first-line symptomatic treatment. 4, 1
• Consider inhaled corticosteroids if cough adversely affects quality of life and persists despite ipratropium. 4

At 8 Weeks (Chronic Cough Threshold)

• When cough persists beyond 8 weeks total duration, the diagnostic approach must fundamentally shift. 4, 3
• Mandatory evaluation includes chest radiography and spirometry. 4, 2
• Systematically evaluate for: upper airway cough syndrome, asthma, eosinophilic bronchitis, and gastroesophageal reflux disease. 4, 3
• These conditions account for the vast majority of chronic cough cases. 4

Critical Pitfalls to Avoid

• Delaying pertussis treatment while waiting for laboratory confirmation decreases effectiveness—treat empirically based on clinical suspicion. 1, 2
• Using subtherapeutic doses of cough suppressants (such as over-the-counter dextromethorphan) is insufficient—use 60 mg for optimal effect. 1, 2
• Misclassifying as chronic cough at 2 weeks has different management implications—chronic cough is defined as >8 weeks. 4, 2
• Forgetting isolation precautions if pertussis is diagnosed can lead to transmission to vulnerable populations. 1, 2
• Using antibiotics indiscriminately for viral post-infectious cough provides no benefit and causes harm. 1, 2, 3

Medication-Induced Cough Consideration

• If the patient is taking an ACE inhibitor, stop it immediately—ACE inhibitor-induced cough typically resolves within days to 2 weeks of discontinuation. 1