What is the best course of action for a patient with a persistent dry cough lasting 3 weeks, without signs of infection, fever, or cold symptoms?

Management of 3-Week Dry Cough Without Fever or Cold Symptoms

For a patient with a 3-week dry cough without fever or cold symptoms, start with inhaled ipratropium bromide as first-line therapy after ruling out pertussis and other serious conditions. 1

Immediate Assessment: Rule Out Red Flags First

Before treating symptomatically, you must exclude serious pathology and pertussis:

• Check vital signs for heart rate ≥100 bpm, respiratory rate ≥24 breaths/min, or temperature ≥38°C to exclude urgent conditions 1, 2
• Perform focused lung examination for asymmetrical lung sounds or focal consolidation 1, 2
• Assess specifically for pertussis features: paroxysmal coughing episodes, post-tussive vomiting, or inspiratory whooping sound 1, 2
  • If any pertussis features are present, obtain nasopharyngeal culture and start macrolide antibiotics immediately without waiting for confirmation 3, 1
  • Pertussis can present atypically without the classic "whoop" 1

Diagnostic Classification

This 3-week dry cough is classified as subacute postinfectious cough (duration 3-8 weeks), which is the most common cause of cough in this timeframe 3, 1, 2

The pathogenesis involves extensive airway inflammation, epithelial disruption, mucus hypersecretion, and transient airway hyperresponsiveness following a presumed viral infection 3

Evidence-Based Treatment Algorithm

First-Line Therapy

Inhaled ipratropium bromide is the only medication with fair-quality evidence demonstrating efficacy in attenuating postinfectious cough 3, 1

• This is the strongest recommendation from the ACCP guidelines with Grade B evidence 3
• It addresses the mucus hypersecretion component of postinfectious cough 3

Second-Line Options (If Ipratropium Fails)

If the cough persists despite ipratropium and adversely affects quality of life:

• Dextromethorphan for dry, bothersome cough, particularly when disrupting sleep 1, 2
• Inhaled corticosteroids may be considered if cough continues to impact quality of life 3, 1
• Short course of oral prednisone (30-40 mg/day) for severe paroxysms, but only after ruling out upper airway cough syndrome, asthma, and GERD 3, 1
• Central-acting antitussives (codeine or dextromethorphan) when other measures fail 3

What NOT to Do

Do not prescribe antibiotics for postinfectious cough—they have no role as the cause is not bacterial infection 3, 1

• This is a Grade I recommendation (no benefit) from ACCP guidelines 3
• Antibiotics only contribute to resistance without providing benefit 1, 4

Critical Pitfalls to Avoid

• Don't assume GERD without typical symptoms like heartburn, sour taste, or regurgitation—empiric PPI therapy is not recommended 1
• Check medication list for ACE inhibitors, which can cause persistent dry cough; if present, stop immediately (median resolution time: 26 days) 2
• Don't miss pertussis by waiting for classic whooping sound—it can present atypically, and early macrolide treatment is critical for preventing transmission 3, 1

Follow-Up Strategy

• Provide reassurance that postinfectious cough typically resolves spontaneously within 3-8 weeks from symptom onset 1, 2
• Schedule follow-up in 4-6 weeks to reassess 1, 2
• If cough persists beyond 8 weeks total, reclassify as chronic cough and initiate systematic evaluation for upper airway cough syndrome, asthma, and GERD 3, 1, 2

Special Considerations

If the patient has upper airway symptoms (nasal congestion, postnasal drip):

• First-generation antihistamine plus decongestant has been shown to decrease cough severity and hasten resolution 2
• This addresses upper airway cough syndrome, which can coexist with postinfectious cough 3