Acute Sinusitis
Acute sinusitis is purulent nasal drainage with congestion and/or facial pain or pressure lasting up to 4 weeks, per the AAO-HNS 2025 Adult Sinusitis Update. Most cases are viral; acute bacterial rhinosinusitis (ABRS) is diagnosed only when symptoms fail to improve within 10 days or clearly worsen after initial improvement ("double sickening").
Symptoms
Facial pain or pressure, nasal congestion, purulent discharge, and reduced sense of smell, sometimes with headache or dental pain in the upper jaw.
Causes and risk
The large majority of acute sinusitis starts as a viral URI; a small fraction becomes secondarily bacterial. Allergies, anatomical variation, and smoking raise risk.
How it is evaluated
Bacterial sinusitis is suspected with symptoms persisting 10+ days, severe onset (fever 39°C-plus with facial pain for 3-4 days), or double sickening -- criteria shared by IDSA and ACP/CDC. Imaging cannot distinguish viral from bacterial sinusitis and is reserved for suspected complications, per ACR Appropriateness Criteria.
Treatment
Two valid strategies exist for confirmed ABRS: watchful waiting with a safety-net prescription, or immediate antibiotics. When treated, first-line therapy is amoxicillin with or without clavulanate for 5-7 days per AAO-HNS 2025 (IDSA favors amoxicillin-clavulanate specifically); doxycycline is the alternative for penicillin allergy. Most people do not need antibiotics at all.
When to seek care
Vision changes, swelling around the eye, severe headache, or confusion suggest orbital or intracranial spread of infection and require immediate care.