Acute Sinus Symptoms and the Antibiotic Question

The short answer#

Most sinus infections do not need antibiotics. The large majority of acute sinus symptoms are caused by a virus, and they resolve on their own, usually improving within about 7 to 10 days. Antibiotics help only the small share of infections that are truly bacterial, and even then the benefit is modest. As a practical rule, a bacterial cause becomes more likely when symptoms last 10 days or more without improving, when they are severe from the start (high fever plus thick nasal discharge or facial pain), or when they clearly worsen after an early improvement. For day-to-day comfort, saline rinses, steroid nasal sprays, and pain relievers do more than antibiotics.

Key points#

• Acute rhinosinusitis is inflammation of the nose and sinuses lasting under four weeks, and most cases are viral, not bacterial.
• Only about 0.5% to 2% of viral upper respiratory infections progress to a true bacterial sinus infection.
• Three patterns raise concern for bacteria: symptoms lasting 10 days or more without improvement, a severe onset (fever of 102 degrees Fahrenheit or 39 degrees Celsius or higher with purulent discharge or facial pain), or "double worsening" after an initial improvement.
• Without antibiotics, roughly 46% of people are cured by one week and 64% by two weeks.
• Antibiotics help only about 5 to 11 more people per 100 recover faster, while about 1 in 8 develop side effects, usually gastrointestinal.
• Watchful waiting with good symptom relief is a mainstream first step for uncomplicated cases, and the 2025 adult sinusitis guideline narrowed the initial observation window to about 3 to 5 days.
• Saline irrigation, intranasal corticosteroid sprays, and simple analgesics have the strongest evidence for easing symptoms.

Do I need antibiotics for a sinus infection?#

For most people, no. Think of acute rhinosinusitis as a spectrum. At one end is the ordinary viral cold that also inflames the sinuses, which is by far the most common situation. At the other end is a bacterial infection, which complicates only about 0.5% to 2% of these illnesses. Because the viral form dominates, prescribing an antibiotic to everyone with sinus symptoms mostly treats people who were going to get better anyway.

The trial evidence backs this up. A Cochrane review of antibiotics for acute rhinosinusitis in adults found that without antibiotics about 46% of people were cured at one week and 64% at two weeks. Adding an antibiotic helped only about 5 to 11 more people per 100 recover faster. Translated into a number needed to treat, that is roughly one extra faster recovery for every 9 to 20 people treated. On the other side of the ledger, about 13 more people per 100 had side effects, mostly diarrhea and other gut upset, which works out to about one in eight. The same review found that antibiotics cleared thick, discolored discharge only slightly faster, one reason mucus color is a poor guide to whether you need them.

Guidelines have moved with this evidence. The Infectious Diseases Society of America reserves antibiotics for cases that meet specific clinical criteria, and the American Academy of Otolaryngology now frames watchful waiting as the default first step for uncomplicated infections, with its 2025 update shortening the initial observation window to about 3 to 5 days before reassessing. Every unnecessary course also feeds a larger problem. For the background, see our explainer on how antibiotic resistance emerges and what stewardship actually does, part of our wider collection on infection, immunity, and cancer.

How long does a sinus infection last?#

Viral sinus symptoms usually peak in the first few days and then ease, with most people meaningfully better within 7 to 10 days, though a lingering stuffy nose or a dulled sense of smell can trail off over another week or two. Clinicians classify sinusitis by duration:

• Acute: under 4 weeks
• Subacute: 4 to 12 weeks
• Chronic: more than 12 weeks

A cold that is improving by day 5 and mostly gone by day 10 is behaving like a virus. What raises a flag is less the total length than the pattern: symptoms that stall past 10 days without any improvement, or that get better and then clearly relapse. A fever early in a cold is common and not by itself alarming. For how to weigh fever on its own, see our guide on fever in adults and when it is just a fever and when it is not.

When is a sinus infection bacterial?#

There is no simple home test, but long clinical experience points to three telltale patterns:

1. Persistent: nasal congestion, discharge, or facial pressure that lasts 10 days or more without improving.
2. Severe onset: a high fever (102 degrees Fahrenheit, or 39 degrees Celsius, or higher) together with thick purulent discharge or notable facial pain, lasting three to four days right at the start of the illness.
3. Double worsening: a cold that was improving around day 5 or 6 and then suddenly gets worse, with new fever, headache, or heavier discharge.

Notice what is not on the list: the color of your mucus. Yellow or green discharge reflects immune cells doing their job and shows up in plenty of ordinary colds, so it cannot tell you whether bacteria are present. Facial pain that worsens when you bend forward, upper-tooth pain, and one-sided symptoms are suggestive but not conclusive. Even when the picture does fit a bacterial infection, many of those cases still settle without antibiotics, which is why a short period of watchful waiting is reasonable for people who are not severely ill.

What actually helps the symptoms?#

Because time does most of the healing, the aim of treatment is comfort. The measures with the most evidence behind them are simple:

• Saline nasal irrigation or spray, to rinse mucus and improve drainage.
• Intranasal corticosteroid sprays, which modestly reduce congestion and facial pressure and help most when allergy is part of the picture.
• Analgesics such as acetaminophen or ibuprofen for pain and fever.
• Rest, fluids, and warm compresses over the cheeks and brow.

Over-the-counter decongestants and antihistamines have weaker support for sinusitis specifically. Short-term oral or nasal decongestants may relieve stuffiness, but decongestant nasal sprays should not be used for more than about three days, to avoid rebound congestion, and antihistamines mainly help when allergies are driving the symptoms.

If antibiotics are prescribed, which one and for how long?#

When the picture does point to bacteria, or when a trial of watchful waiting has not helped, guidelines favor amoxicillin, with or without clavulanate, as the first choice for most adults. Doxycycline is a common alternative for people with a penicillin allergy. Current guidance leans toward shorter treatment, generally about 5 to 7 days for uncomplicated adult cases rather than the longer courses used in the past, because shorter courses work about as well with fewer side effects. Our piece on why shorter antibiotic courses are often enough walks through the reasoning. If you are not clearly improving after 3 to 5 days on an antibiotic, that is a reason to check back with your clinician rather than simply pushing through the bottle.

When to seek care#

Some warning signs point to a spreading infection or a complication and deserve prompt medical attention:

• Swelling, redness, or bulging around an eye, or vision changes such as double or blurred vision.
• A severe or rapidly worsening headache, neck stiffness, confusion, or new drowsiness.
• Swelling of the forehead or face.
• A high fever that persists or keeps climbing.
• Symptoms lasting more than 10 days without any improvement, or that improve and then clearly worsen.
• Repeated recurrences within a year, symptoms lasting beyond four weeks, or any sinus infection in someone with a weakened immune system.

These complications are uncommon, but infection around the eye or brain can develop quickly, so do not try to wait those signs out.

It cannot account for your particular history. For a diagnosis or a treatment decision, talk with a licensed clinician who can evaluate you directly.