Postviral Rhinosinusitis

Postviral rhinosinusitis is persistent sinonasal inflammation that follows a viral cold and lasts beyond 10 days, up to 12 weeks, without the features of bacterial infection. Mucosal swelling, impaired mucociliary clearance and ostial obstruction sustain the symptoms after the virus has cleared.

• It is usually not bacterial and does not need antibiotics.
• Allergy, smoking, reflux and nasal structural problems prolong it.
• Postviral loss of smell can follow and may last months.

Persisting nasal blockage, mucoid or clear discharge, postnasal drip, facial pressure, cough and reduced smell, with no fever and no worsening after the first week.

• Differential diagnosis: acute bacterial sinusitis, allergic rhinitis, chronic rhinosinusitis with or without polyps, nasal polyps, deviated septum, adenoid hypertrophy in children, laryngopharyngeal reflux, fungal sinusitis, granulomatosis with polyangiitis, tumour.
• Complications: progression to chronic rhinosinusitis, bacterial superinfection, persistent anosmia, sleep disturbance.

Diagnosis is clinical, with nasal endoscopy when symptoms continue beyond 4 weeks.

• Anterior rhinoscopy and endoscopy for mucosal oedema, polyps and purulence.
• CT of the sinuses if symptoms continue beyond 12 weeks or complications are suspected.
• Allergy testing and smell testing when relevant.

Treat the inflammation and avoid unnecessary antibiotics.

• Supportive: saline irrigation twice daily, steam, adequate hydration, avoid smoking and irritants, smell training twice daily with four scents for 12 weeks.
• Pharmacological: mometasone nasal spray 200 micrograms twice daily or fluticasone propionate 2 sprays per nostril daily for 3 to 4 weeks; loratadine 10 mg or cetirizine 10 mg daily if allergic; short course of prednisolone 30 mg daily for 5 to 7 days for severe obstruction or loss of smell; amoxicillin clavulanate 625 mg three times daily for 7 days only if bacterial features develop.
• Procedures: nasal endoscopy; endoscopic sinus surgery after maximal medical therapy fails.
• Special groups: pregnancy, saline and intranasal steroids; children, saline, steroid spray and examination for adenoid hypertrophy; diabetes, check glucose before oral steroids.
• Red flags: unilateral blockage or bleeding, orbital signs, severe headache, neck stiffness, cranial nerve palsy, symptoms beyond 12 weeks.
• Follow-up: review at 4 weeks; refer if there is no improvement or symptoms exceed 12 weeks.