If you’ve had nasal congestion, facial pressure, and thick discharge for more than a week with no sign of improvement, there’s a good chance you’re dealing with a sinus infection rather than a common cold. The key distinction comes down to timing and trajectory: colds improve within 7 to 10 days, while sinus infections either persist beyond that window or get worse after briefly getting better.
The Symptoms That Point to a Sinus Infection
Sinus infections (sinusitis) share many symptoms with colds and allergies, which is why they’re so easy to confuse. The hallmark symptoms include thick nasal discharge, pressure or pain around your eyes, cheeks, nose, or forehead, and a reduced sense of smell. Headaches are common. A cough and sore throat can also show up, though they’re less typical.
What really separates a sinus infection from a cold is the pattern. A cold follows a predictable arc: you feel worse for a few days, then gradually improve. A sinus infection either plateaus without improving for 10 or more days, or it follows a “double worsening” pattern where you start feeling better around day 4 to 7 and then suddenly get worse again. That second wave is one of the most reliable signs that something beyond a simple virus is going on.
Sinus Infection, Cold, or Allergies?
A cold and a sinus infection can look nearly identical in the first week. Both cause congestion, discharge, and facial pressure. The 10-day mark is your clearest dividing line. If symptoms are still present and haven’t improved at all after 10 days, a sinus infection is the more likely explanation. If you’re steadily improving, even slowly, it’s probably just a cold running its course.
Allergies are easier to rule out. Itchy, watery eyes are a telltale sign of allergies and rarely show up with sinus infections. Allergies also tend to follow seasonal patterns: tree pollen peaks in spring, grass pollen in late spring and early summer, ragweed in fall. If your symptoms line up with a specific time of year and include itching, an antihistamine is a reasonable first step. If it works, allergies are your answer.
One common myth worth clearing up: the color of your mucus doesn’t reliably tell you whether you have an infection. Green or yellow discharge can show up with colds, allergies, and sinus infections alike.
Why Sinus Infections Happen
Your sinuses are air-filled cavities connected to your nasal passages through tiny openings only 1 to 3 millimeters wide. When something causes the lining of those openings to swell, whether it’s a virus, allergies, or chemical irritation, the drainage pathway gets blocked. Mucus builds up, oxygen levels inside the sinus drop, and the environment shifts in favor of bacterial growth.
That trapped, low-oxygen environment also impairs the tiny hair-like structures that normally sweep mucus out of your sinuses. Once that self-cleaning mechanism breaks down, bacteria that are normally present in your nasal passages can take hold and multiply. This is why most bacterial sinus infections start as viral colds. The virus causes the initial swelling, and bacteria move in once drainage stalls.
Most Sinus Infections Don’t Need Antibiotics
The vast majority of sinus infections are caused by viruses and clear up on their own within a week to 10 days. Only about 0.5 to 2 percent of acute sinus infections are bacterial. Even when a bacterial infection does develop, it can still resolve without antibiotics. Current guidelines from the American Academy of Otolaryngology (updated in 2025) support an initial observation period of 3 to 5 days for otherwise healthy adults with suspected bacterial sinusitis, with antibiotics reserved for those who don’t improve.
The criteria that suggest a bacterial infection, and the point where antibiotics become worth considering, include: symptoms lasting 10 days or more without improvement, a fever of 102°F or higher combined with facial pain and nasal discharge lasting 3 to 4 days, or the double-worsening pattern described above.
What You Can Do at Home
Saline nasal irrigation is one of the most effective things you can do while waiting for a sinus infection to resolve. Flushing your nasal passages with salt water helps thin mucus, reduce swelling, and physically wash out irritants and bacteria. You can use a neti pot, squeeze bottle, or bulb syringe once or twice daily while you have symptoms. To make your own solution, mix one to two cups of distilled or previously boiled water with a quarter to half teaspoon of non-iodized salt. Never use tap water directly, as it can introduce harmful organisms.
Beyond saline rinses, staying well hydrated helps keep mucus thin. Warm compresses over your sinuses can ease facial pressure. Over-the-counter pain relievers help with headaches and discomfort. Decongestant sprays can open up blocked passages in the short term, but using them for more than 3 days can cause rebound congestion that makes things worse.
Symptoms That Need Immediate Attention
Sinus infections rarely become dangerous, but the sinuses sit close to the brain and eyes, so complications can be serious when they do occur. Go to an emergency room if you develop a fever over 103°F, vision changes (especially with pain or swelling around the eyes), confusion, a stiff neck, or seizures. These can signal that the infection has spread beyond the sinuses and requires urgent treatment.