Most sinus infections last 7 to 10 days and clear up on their own without antibiotics. These are almost always caused by a virus, the same type that causes the common cold. Some people have lingering symptoms for up to four weeks, and infections that drag on beyond 12 weeks are classified as chronic sinusitis, a different condition that requires a different approach.
Viral Sinus Infections: 7 to 10 Days
The vast majority of sinus infections are viral. Symptoms typically peak around days 3 to 5, with facial pressure, congestion, thick nasal discharge, and sometimes a low-grade fever. By the end of the first week, most people notice steady improvement. The full timeline from start to finish is usually 7 to 10 days, though a mild cough or residual congestion can linger a bit longer.
Because these infections are viral, antibiotics won’t help. Over-the-counter decongestants, saline rinses, and pain relievers are the standard approach while your body fights off the virus. Staying hydrated and using a humidifier can also ease congestion during that window.
When It Might Be Bacterial
A small percentage of sinus infections become bacterial, and the main clue is time. If your symptoms persist for 10 days or more without any improvement, a bacterial infection is the likely cause. Two other patterns also point to bacteria: a high fever (102°F or above) paired with facial pain and thick nasal discharge lasting 3 to 4 days, or symptoms that seem to improve after the first week only to come back worse.
Bacterial sinus infections generally take longer to resolve without treatment and are the cases where antibiotics make a real difference. Guidelines recommend a 5 to 7 day antibiotic course for uncomplicated cases, though in practice many prescriptions are written for 10 days. Most people start feeling noticeably better within 2 to 3 days of starting antibiotics, but finishing the full course matters.
Subacute and Chronic Sinusitis
Not every sinus infection follows the standard timeline. When symptoms persist for 4 to 8 weeks despite initial treatment, this is considered subacute sinusitis. It sits in a gray zone between a straightforward acute infection and something more long-term.
Chronic sinusitis is diagnosed when symptoms last 12 consecutive weeks or longer. The diagnostic threshold requires at least two of four key symptoms: facial pain or pressure, reduced or lost sense of smell, nasal drainage, and nasal obstruction. Chronic sinusitis is less about a single infection and more about ongoing inflammation in the sinuses. It can be driven by allergies, nasal polyps, or structural issues like a deviated septum. Treatment often involves nasal steroid sprays, saline irrigation, and sometimes surgery to improve sinus drainage.
Sinus Infections in Children
Children get sinus infections more frequently than adults, partly because their sinuses are still developing and partly because they catch more colds. The same 10-day rule applies for distinguishing viral from bacterial infections in kids. However, when antibiotics are needed, children typically take them for 10 to 14 days, roughly double the adult course. This longer duration reflects how children’s immune systems and sinus anatomy handle the infection differently.
In young children, the symptoms can also look a bit different. A persistent thick, green or yellow nasal discharge lasting more than 10 days is often the biggest red flag, since kids may not articulate facial pressure or headache the way adults do.
What Affects How Long Yours Lasts
Several factors influence whether your sinus infection resolves quickly or drags on. Allergies are one of the biggest. If you have ongoing allergic inflammation in your nasal passages, your sinuses drain poorly, creating an environment where infections linger. Smoking or regular exposure to secondhand smoke also slows recovery by irritating the mucous membranes that line the sinuses.
People with weakened immune systems, whether from a medical condition or medication, tend to have longer and more frequent infections. Structural issues like nasal polyps or a deviated septum can trap mucus and make it harder for even a simple viral infection to clear. If you find yourself getting sinus infections several times a year or your symptoms routinely push past the 4-week mark, these underlying factors are worth investigating.
Tracking Your Symptom Timeline
Paying attention to the pattern of your symptoms matters more than counting exact days. The critical distinction is whether things are getting better or staying the same. A sinus infection that’s gradually improving over 10 to 12 days is still likely viral and running its course. One that plateaus or worsens after the first week is more concerning. The “double worsening” pattern, where you feel better for a few days and then take a clear turn for the worse, is one of the most reliable signs that bacteria have moved in and you may benefit from treatment.