Likely Diagnosis: Postinfectious Upper Airway Cough Syndrome (UACS) Following Viral Rhinosinusitis
This patient has postinfectious upper airway cough syndrome following a viral upper respiratory infection that has now entered the resolution phase, and does not require antibiotics at this time. 1, 2
Clinical Reasoning
Why This Is NOT Acute Bacterial Rhinosinusitis
The timeline argues against bacterial superinfection. The American Academy of Otolaryngology-Head and Neck Surgery states that bacterial sinusitis should be diagnosed when symptoms persist beyond 10 days without improvement OR when symptoms worsen after 5-7 days. 1 This patient's symptoms began improving on day 14-15 (mucus becoming less thick, changing from green to yellow), which is the opposite pattern expected with bacterial infection.
The natural history fits viral infection. Viral URIs commonly cause nasal congestion and cough that persist into the second and third week, with fever and myalgia resolving after 5 days. 1 This patient's progression—with throat symptoms peaking on day 13 then resolving, and mucus quality improving by day 15—matches the expected course of uncomplicated viral rhinosinusitis.
Colored nasal discharge alone does not indicate bacterial infection. The American Academy of Otolaryngology-Head and Neck Surgery explicitly states that mucopurulent nasal secretions occur after a few days of viral infection due to neutrophil influx and are not specific for bacterial infection. 1
Why This IS Postinfectious UACS
The key diagnostic feature is present: a history of upper respiratory tract infection. The American College of Chest Physicians identifies this as the key to diagnosing postinfectious UACS. 1, 2
The persistent symptoms fit the postinfectious pattern. Postinfectious cough is defined as lasting >3 weeks after acute symptoms but resolving within 8 weeks, caused by extensive disruption of epithelial integrity and widespread airway inflammation. 2 This patient is on day 18 with improving but persistent hoarseness, cough, and nasal drainage.
The unilateral sinus congestion and hoarseness are consistent. The American College of Chest Physicians notes that cough from sinusitis can be productive or nonproductive, and chronic sinusitis may cause cough without typical acute sinusitis findings. 1, 2
Treatment Recommendations
Treat with a first-generation antihistamine combined with a decongestant (e.g., pseudoephedrine). 1, 2 The American College of Chest Physicians specifically recommends this combination for postinfectious UACS, noting it works similarly to treatment for acute viral URI cough.
Additional Supportive Measures
Consider inhaled ipratropium for persistent lower airway symptoms (the semi-productive cough and transient chest heaviness). 2
Saline nasal irrigation can help with the persistent unilateral congestion and postnasal drainage. 3
Avoid antibiotics unless symptoms worsen or fail to resolve within 8 weeks total duration. 2 The American College of Chest Physicians advises against assuming persistent cough after sinusitis requires continued antibiotics, as most postinfectious cough is not due to ongoing bacterial infection.
Contagion Status
This patient is likely no longer significantly contagious. 1
Viral shedding typically peaks in the first 2-3 days of symptoms and substantially decreases by day 7-10. 1
At day 18, with symptoms improving rather than worsening, viral load should be minimal to absent. 1
The improving quality of secretions (less thick, yellow rather than green) suggests resolution of active infection. 1
However, some viral shedding may persist for up to 2-3 weeks in certain viral infections, so basic respiratory hygiene (hand washing, covering coughs) remains prudent. 1
Critical Pitfalls to Avoid
Do not prescribe antibiotics based on symptom duration alone. The key is whether symptoms are improving or worsening. 1 This patient's symptoms are improving, making bacterial superinfection unlikely.
Do not assume all persistent cough requires imaging or antibiotics. Postinfectious cough lasting 3-8 weeks is expected and self-limited. 2
Reassess if symptoms persist beyond 8 weeks total or worsen at any point. At that juncture, consider alternative diagnoses including asthma, gastroesophageal reflux, or true chronic bacterial sinusitis. 2
Watch for red flags suggesting complications: high fever returning, severe unilateral facial pain, vision changes, or mental status changes would require urgent evaluation for complications. 1