Page Summary
- Acute sinusitis causes cloudy or colored nasal drainage together with nasal blockage and/or facial pain or pressure.
- The drainage may be white, yellow or green and still be caused by a virus. Color alone does not mean the infection is bacterial.
- Bacterial sinusitis becomes more likely when symptoms persist for 10 days without improvement, or improve and then clearly worsen again.
- Treatment depends on the duration and pattern of symptoms; antibiotics are not always needed immediately.
Acute Sinusitis
Acute sinusitis (acute rhinosinusitis) causes cloudy or colored nasal drainage together with nasal blockage and/or facial pain or pressure, and lasts less than four weeks. It commonly develops during or after a viral upper respiratory infection.
If you are in the first few days of a cold with clear nasal discharge, congestion, sneezing, sore throat or cough, see The Common Cold — When Do I Need Antibiotics?
Common symptoms
- Cloudy or colored nasal drainage.
- Nasal blockage or congestion.
- Facial pressure or pain.
- Reduced sense of smell.
- Sometimes fever or dental pressure.
When could it be a bacterial sinus infection?
A bacterial sinus infection becomes more likely when typical acute sinusitis symptoms continue for at least 10 days without improvement, or when you begin to improve and then clearly become worse again (“double worsening”).
Yellow or green nasal discharge on its own does not establish a bacterial infection. Mucus commonly changes color during a viral illness. The pattern and duration of your symptoms matter far more than their color.
How is it diagnosed?
Diagnosis is usually based on your symptoms, how long they have lasted, and an examination of the nose. A nasal endoscopy may be used when needed to look more closely inside the nose and the openings of the sinuses.
A CT scan is usually not needed for uncomplicated acute sinusitis. Imaging may be needed if a complication or another diagnosis is suspected.
Treatment
Viral sinusitis usually improves with supportive care and topical nasal treatments such as saline irrigation or nasal sprays. Oral steroids are not routinely needed and are only used in selected situations.
Antibiotics and watchful waiting
Antibiotics are not automatically required the moment a bacterial sinus infection is suspected. There is usually more than one reasonable approach.
- Some patients prefer to start antibiotics once bacterial sinusitis is reasonably suspected. That is a sound choice.
- Others prefer to avoid antibiotics while it is safe to keep observing.
- For an uncomplicated infection with reliable follow-up, continuing symptomatic treatment and watching for another 3–5 days is an option.
- If symptoms first meet the criteria around day 10 and remain unimproved around day 14–15, antibiotics become increasingly appropriate.
- Persistent or worsening symptoms approaching 15–20 days should be reassessed rather than observed indefinitely. There is no fixed day at which antibiotics automatically begin.
Double worsening can happen before day 10 and raises greater suspicion for bacterial infection, so antibiotics are more likely to be recommended after clinical assessment in that situation.
The right choice depends on your symptoms, how the illness is progressing, your general health and your own preferences. The Common Cold — When Do I Need Antibiotics? goes through the timing in more detail.
When infections keep coming back
Four or more separate episodes in a year, with complete recovery in between, are assessed differently. That page covers why episodes recur and what can be done about it.
Frequently asked questions
Is acute sinusitis the same as chronic sinusitis?
No. Acute sinusitis usually clears up within a few weeks, and you feel completely well afterward. Chronic sinusitis means symptoms last 12 weeks or more, or keep coming back without fully going away.