A sinus infection typically announces itself with a combination of thick, discolored nasal discharge, facial pain or pressure, and congestion that lasts longer than a typical cold. The key distinction isn’t any single symptom but the pattern: symptoms that persist without improvement for at least 10 days, or symptoms that start getting better and then suddenly worsen again.
The Core Symptoms
Sinus infections share several symptoms with colds and allergies, which is exactly why they’re hard to identify on your own. The hallmark combination is thick yellow or green mucus draining from your nose (or down the back of your throat), nasal congestion, and facial pain or pressure. Most people also experience headache, sore throat from post-nasal drip, cough, bad breath, and fatigue. A low-grade fever is possible but not universal.
What sets a sinus infection apart from a garden-variety cold is that these symptoms tend to be more intense and more persistent. The congestion feels heavier. The facial pressure feels localized and specific rather than vague. And it doesn’t follow the usual arc of a cold, which peaks around day three or four and then gradually improves.
Where Your Face Hurts Tells You Which Sinuses Are Involved
You have four pairs of sinus cavities, and the location of your pain maps directly to which ones are inflamed. Pain in your forehead points to the frontal sinuses. Aching in your cheekbones or upper teeth suggests the maxillary sinuses, the large ones behind your cheeks. Pain in the bridge of your nose involves the ethmoid sinuses. And pain behind your eyes or deep in your ears can come from the sphenoid sinuses, which sit further back in your skull.
You can do a rough check at home by gently pressing with your thumb just below your eyebrows (over the bony ridge, avoiding the eye socket) and then below your cheekbones on either side of your nose. Use light, circular pressure. A slight sense of pressure is normal. If either spot feels distinctly tender or painful, that’s consistent with sinus inflammation.
The 10-Day Rule
Most colds are caused by viruses and resolve within 7 to 10 days. The clinical standard for diagnosing a bacterial sinus infection relies heavily on timing. If you have purulent (thick, discolored) nasal discharge along with congestion, facial pain, or pressure that persists without any improvement for at least 10 days after your symptoms started, that pattern points to a bacterial infection rather than a lingering cold.
There’s a second pattern worth knowing, sometimes called “double worsening.” This is when your cold symptoms start improving, and then within 10 days they take a clear turn for the worse: the congestion comes roaring back, the facial pressure intensifies, or you develop a new fever. That rebound strongly suggests a bacterial infection has set in on top of the original viral illness. It’s one of the most reliable signals you’re dealing with something that may need treatment beyond rest and fluids.
Sinus Infection vs. Allergies
Allergies and sinus infections overlap in frustrating ways. Both cause congestion, a runny nose, and post-nasal drip. But there are several reliable ways to tell them apart.
Itchiness is the biggest giveaway for allergies. If your eyes are itchy and watery, you’re sneezing frequently, and you’re rubbing the corners of your eyes, that pattern is far more typical of allergic rhinitis than infection. Sinus infections generally don’t feel itchy at all.
Mucus color matters, though with a caveat. Yellow or green discharge is more common with infections and suggests a more significant inflammatory process than a simple allergic reaction, which typically produces clear, watery mucus. That said, mucus color alone isn’t definitive. Your body can produce yellowish mucus during a viral cold too, and some bacterial infections produce relatively clear drainage. It’s one piece of the puzzle, not the whole picture.
Timing also helps. Seasonal allergies tend to flare predictably during certain months and respond quickly to antihistamines. A sinus infection develops over days, often on the tail end of a cold, and doesn’t improve with allergy medication.
Sinus Infection vs. a Cold
Every sinus infection starts as something else, usually a cold. The virus causes swelling in the sinus lining, which traps mucus and creates a warm, stagnant environment where bacteria can thrive. This is why the two conditions feel so similar in the early days.
The practical distinction comes down to trajectory. A cold follows a predictable curve: you feel progressively worse for two to three days, plateau, and then gradually improve. By day seven or eight, you’re clearly on the mend even if you’re not fully recovered. A sinus infection either plateaus and refuses to improve past that 10-day mark, or it follows the double-worsening pattern where improvement reverses into a second wave of symptoms. Facial pain and pressure that gets worse when you bend forward is also more characteristic of a sinus infection than a cold.
Signs in Children
Kids with sinus infections often look different from adults. Rather than complaining about facial pressure, children are more likely to have a persistent cough (especially at night from post-nasal drip), bad breath, crankiness, low energy, and swelling around the eyes. The nasal discharge is typically thick and yellow-green.
Children’s adenoid tissue, located at the back of the nose, can also become infected and produce symptoms nearly identical to sinusitis: runny nose, congestion, post-nasal drip, cough, and headache. This overlap makes pediatric sinus infections particularly tricky to identify without a professional evaluation, especially in younger children who can’t describe what they’re feeling.
What a Diagnosis Actually Looks Like
There’s no simple at-home test for a sinus infection. Diagnosis is based on your symptoms, their timeline, and a physical exam. Your provider will ask how long you’ve been sick, whether symptoms improved and then worsened, and will examine your nose and face. Imaging like a CT scan isn’t typically needed for a straightforward case and is reserved for infections that don’t respond to treatment or keep coming back.
The most useful thing you can do before an appointment is track your timeline. Note when your symptoms started, whether they improved at any point, and when they got worse again. That narrative is often more diagnostically valuable than any single symptom. A provider hearing “I had a cold that was getting better around day five, but then on day eight my congestion came back worse and I developed facial pain and a fever” has a much clearer picture than “I’ve been congested for a while.”
Symptoms That Need Prompt Attention
Most sinus infections, even bacterial ones, are not dangerous. But in rare cases, infection can spread beyond the sinuses to nearby structures. Seek immediate care if you develop a high fever (above 104°F), severe headache that doesn’t respond to pain relievers, visual changes or swelling around the eye, stiff neck, confusion, or swelling and redness spreading across your forehead or face. These can signal complications that require urgent treatment.