Acute rhinosinusitis / URI antibiotics
Recommendations
AAO-HNSF2025Grade Strong recommendation (diagnosis); Recommendation (treatment)
Most acute rhinosinusitis is viral. Diagnose bacterial sinusitis when symptoms persist without improvement for at least 10 days, or worsen within 10 days after initial improvement (double worsening). For uncomplicated ABRS, offer watchful waiting without antibiotics when follow-up is assured. If treating, amoxicillin with or without clavulanate is first-line, for 5 to 7 days in most adults (shortened from 5 to 10 days).
Verify at AAO-HNSF (opens in a new tab)CDC2024
Acute bronchitis: routine antibiotics are not recommended, regardless of cough duration. Pharyngitis: confirm group A strep with a rapid antigen test before treating. Sinusitis: diagnose bacterial infection only if severe (fever ≥39°C with purulent discharge or facial pain for more than 3-4 days), persistent over 10 days without improvement, or worsening after initial improvement; encourage watchful waiting for uncomplicated cases with reliable follow-up; first-line amoxicillin or amoxicillin/clavulanate.
Verify at CDC (opens in a new tab)AAO-HNSF2025Grade Recommendation / Option
Do not image acute rhinosinusitis unless a complication or alternative diagnosis is suspected. Analgesics, intranasal corticosteroids, and/or saline irrigation are options for symptom relief in viral or bacterial sinusitis. If there is no improvement or worsening after 3 to 5 days of an appropriate antibiotic, reassess to confirm ABRS, exclude other causes, and look for complications; if ABRS is confirmed, change the antibiotic.
Verify at AAO-HNSF (opens in a new tab)Who this applies to
- Most acute rhinosinusitis is viral and resolves within 10 days without antibiotics.
- Suspect bacterial infection only with symptoms 10 days or more without improvement, or double worsening, meaning improvement followed by worsening within 10 days (AAO-HNSF 2025). The CDC (2024) also counts a severe onset: fever of 39 C (102 F) or higher with purulent nasal discharge or facial pain for more than 3 to 4 days.
- The common cold, nonspecific upper respiratory infection and acute bronchitis in otherwise healthy adults: no antibiotics (ACP and CDC 2016, restated by CDC 2024).
How it is done in practice
- Uncomplicated bacterial sinusitis: offer watchful waiting without antibiotics when follow-up is assured (AAO-HNSF 2025), and the CDC also encourages it. How long to wait depends on when and how the diagnosis was made.
- If treating: amoxicillin with or without clavulanate for 5 to 7 days in most adults (AAO-HNSF 2025; the CDC also lists either as first line). Penicillin allergy: doxycycline, or a respiratory fluoroquinolone (CDC 2024) reserved for those with no other option because of the FDA boxed warning.
- Avoid macrolides such as azithromycin because of pneumococcal resistance (CDC 2024). The now-archived IDSA 2012 guideline also advised against trimethoprim-sulfamethoxazole and against second- or third-generation oral cephalosporins alone.
- Symptom care regardless of cause: saline irrigation, an intranasal steroid, analgesics. Decongestants briefly; antihistamines only when allergy is part of the picture.
- Imaging has no role in uncomplicated acute sinusitis. CT is for suspected orbital or intracranial complications, recurrent disease, or symptoms past 12 weeks.
What changed recently
The AAO-HNSF 2025 update is now the main U.S. adult guideline, since IDSA archived its 2012 one. It made watchful waiting the offered first approach for uncomplicated bacterial sinusitis, shortened the usual course from 5 to 10 days to 5 to 7, and diagnoses on persistence or double worsening only. The CDC 2024 outpatient guidance still counts a severe onset and keeps amoxicillin or amoxicillin-clavulanate as first line.
Points that matter in clinic
- Colored discharge alone does not mean bacteria. Duration and the double-worsening pattern carry the diagnosis.
- Urgent referral: periorbital swelling, vision change, severe headache, altered mental status, or high fever with a toxic appearance.
- No improvement or worsening after 3 to 5 days of an appropriate antibiotic: reassess to confirm the diagnosis, rule out other causes and look for complications, then change the antibiotic if it is still bacterial sinusitis.