Most Likely Diagnosis: Acute Viral Upper Respiratory Infection (Common Cold) or Post-Infectious Cough
This is almost certainly a self-limited viral upper respiratory infection that has progressed into the post-infectious cough phase, requiring only reassurance and symptomatic management—not antibiotics or extensive workup.
Clinical Assessment
Key Diagnostic Features Present
- Two-week duration of cough, fatigue, and congestion without fever strongly suggests viral etiology rather than bacterial infection 1.
- The absence of fever, purulent sputum, focal lung findings, or systemic toxicity makes bacterial pneumonia or sinusitis highly unlikely 1.
- At 2 weeks, this falls into the typical timeframe for post-infectious cough (which lasts 3-8 weeks after viral URI) 2, 3.
Red Flags to Exclude (None Present Here)
- No hemoptysis, significant dyspnea, or chest pain 1.
- No fever >38°C, tachycardia >100 bpm, or tachypnea >24 breaths/min that would suggest pneumonia 2.
- No paroxysmal coughing with post-tussive vomiting or inspiratory "whoop" that would indicate pertussis 2, 3.
Evidence-Based Management
What TO Do
First-line symptomatic treatment:
- Recommend simple home remedies such as honey and lemon, adequate hydration, and rest 1.
- Over-the-counter guaifenesin (200-400 mg every 4 hours, up to 6 times daily) can help loosen secretions 2.
- Dextromethorphan 60 mg (higher than typical OTC dosing) provides maximum cough suppression if cough is particularly bothersome 1, 2.
- Menthol lozenges or vapor inhalation for short-term symptomatic relief 1.
If symptoms persist or worsen beyond 2-3 weeks:
- Consider inhaled ipratropium bromide 2-3 puffs four times daily, which has the strongest evidence for attenuating post-infectious cough, with response expected within 1-2 weeks 2.
- For prominent nasal congestion, add a first-generation antihistamine-decongestant combination plus intranasal corticosteroid spray 1, 2.
What NOT To Do
Antibiotics are explicitly contraindicated:
- Do not prescribe antibiotics (amoxicillin, azithromycin, or any other)—they provide zero benefit for viral post-infectious cough, contribute to antimicrobial resistance, and cause unnecessary adverse effects 1, 2, 4.
- The presence of colored or green sputum does NOT indicate bacterial infection in this context 2.
Avoid premature escalation:
- Do not jump to oral prednisone—it should be reserved only for severe paroxysmal cough that significantly impairs quality of life after ruling out other causes 2.
- Do not order chest X-ray unless cough persists beyond 8 weeks total, or if red flags develop (fever, hemoptysis, weight loss, night sweats) 2, 3.
Expected Timeline & Follow-Up
- Most post-viral coughs resolve spontaneously within 3-8 weeks from initial infection onset 2, 3.
- Instruct the patient to return immediately if fever develops, hemoptysis occurs, dyspnea worsens, or symptoms fail to improve within 3-5 days of symptomatic treatment 2.
- If cough persists beyond 8 weeks total, reclassify as chronic cough and systematically evaluate for upper airway cough syndrome, asthma, and GERD 2, 3.
Common Pitfalls to Avoid
- Misdiagnosing acute bronchitis as requiring antibiotics when it is actually viral post-infectious cough 1.
- Failing to recognize that one-third of patients labeled "acute bronchitis" actually have undiagnosed mild asthma—maintain suspicion if patient has had ≥2 similar episodes in past 5 years 1.
- Overlooking pertussis in patients with prolonged paroxysmal cough, especially if unvaccinated or in outbreak settings 2, 3.
- Prescribing codeine or other opiates, which have significant adverse effects without superior efficacy compared to dextromethorphan 1, 2.