What is the appropriate evaluation and initial management for a 20-year-old patient with a cough lasting two weeks?

Evaluation and Management of 2-Week Cough in a 20-Year-Old

For a 20-year-old with a 2-week cough, immediately consider pertussis as the primary diagnosis if there are paroxysmal coughing fits, post-tussive vomiting, or inspiratory whooping—and start azithromycin 500 mg daily for 3-5 days without waiting for laboratory confirmation. 1, 2

Initial Diagnostic Priorities

Screen for pertussis features immediately:

• Any cough lasting ≥2 weeks with paroxysmal episodes should be considered pertussis until proven otherwise 1, 2
• Look specifically for paroxysmal coughing fits, post-tussive vomiting, or inspiratory whooping sound 1, 2
• Obtain nasopharyngeal aspirate or Dacron swab for culture confirmation, but do not delay treatment while waiting for results 1, 3

Assess for red flags requiring urgent workup:

• Hemoptysis, constitutional symptoms (fever, weight loss), respiratory distress, or hypoxemia mandate immediate further investigation 1, 2
• Tachypnea (≥24 breaths/min), tachycardia (≥100 bpm), fever (≥38°C), or focal lung findings suggest pneumonia 3
• Asymmetrical lung sounds, focal consolidation, or pleural effusion warrant chest radiography 3
• Risk factors for malignancy (age >40, smoking history >30 pack-years) require chest imaging 1

Obtain key historical details:

• ACE inhibitor use—stop immediately if present, as cough typically resolves within days to 2 weeks (median 26 days) 4, 1
• Smoking status—cessation is first-line treatment, with most coughs resolving within 4 weeks 4, 1
• Endemic area residence or high-risk populations for tuberculosis 4

Treatment Algorithm

If Pertussis is Suspected:

• Start azithromycin 500 mg once daily for 3-5 days immediately 1, 2
• Isolate the patient for 5 days from the start of antibiotic treatment to prevent transmission 1, 2
• Early treatment within the first 2 weeks decreases paroxysms and prevents transmission 1

If Post-Viral Acute Cough (No Pertussis Features):

• Do not use antibiotics—they provide no benefit for viral post-infectious cough and contribute to resistance 1, 2, 3
• Most viral URTI-associated coughs resolve within 2 weeks spontaneously 2
• Ipratropium inhalation is first-line for cough suppression 1, 2
• Dextromethorphan 60 mg (not over-the-counter subtherapeutic doses) is recommended when other measures fail 1, 2
• Prednisone 30-40 mg/day for a short period may be used for severe paroxysms 1

Timeline Classification and Reassessment

At 2 weeks, this is still acute cough (defined as <3 weeks duration): 4, 2

• The differential diagnosis and management strategy differ from subacute or chronic cough 1
• Most viral coughs resolve by this point, so persistence raises concern for pertussis or evolving post-viral cough 2

If cough persists to 3 weeks:

• Consider post-infectious cough and trial ipratropium 1
• Subacute cough (3-8 weeks) is generally expected to resolve spontaneously from postviral airway inflammation, bronchial hyperresponsiveness, and mucus hypersecretion 3

If cough persists beyond 8 weeks:

• Mandatory full workup as chronic cough, including chest radiography and spirometry 1, 2, 3
• Systematically evaluate for upper airway cough syndrome, asthma, eosinophilic bronchitis, and gastroesophageal reflux disease 3

Critical Pitfalls to Avoid

• Delaying pertussis treatment while waiting for laboratory confirmation decreases effectiveness 1, 2, 3
• Using antibiotics indiscriminately for viral post-infectious cough provides no benefit and contributes to resistance 1, 2, 3
• Using subtherapeutic doses of over-the-counter dextromethorphan is insufficient—60 mg is needed for optimal effect 1, 2
• Forgetting isolation precautions if pertussis is diagnosed can lead to transmission 1, 2
• Misclassifying as chronic cough at 2 weeks has different management implications—this is still acute cough 1, 2

When to Escalate

• Any patient with massive hemoptysis requires immediate pulmonology consultation 2
• Recurrent hemoptysis or risk factors for malignancy require bronchoscopy or high-resolution CT even if initial chest radiograph is normal 2
• Maintain suspicion for workplace sensitizers or chemical exposures if cough fails to improve as expected 3