A sinus infection typically announces itself with three hallmark symptoms: thick, discolored nasal discharge, nasal congestion or obstruction, and facial pain or pressure. But since a common cold causes many of the same symptoms, the real question is usually not “what does a sinus infection feel like” but “how do I know this isn’t just a cold?” The answer comes down to timing, the pattern of your symptoms, and a few specific clues.
The Three Timing Patterns That Point to a Sinus Infection
Most sinus infections start as a regular cold. The virus causes inflammation in your sinuses, fluid gets trapped, and bacteria can multiply in that warm, moist environment. Because of this overlap, doctors rely heavily on how long symptoms last and how they change over time. The CDC and the Infectious Diseases Society of America identify three patterns that suggest a bacterial sinus infection rather than a viral cold:
- Symptoms lasting 10 days or more without improvement. A typical cold gets noticeably better within 7 to 10 days. If your congestion, facial pressure, and discharge are just as bad on day 10 as they were on day 4, that persistence points toward a sinus infection.
- Severe symptoms from the start. A high fever (102°F or higher) along with facial pain and discolored nasal discharge lasting 3 to 4 consecutive days is more than a cold usually produces.
- “Double sickening.” You start to feel better after 4 to 7 days, then suddenly get worse again. This second wave, where symptoms that were improving take a clear turn for the worse, is one of the most reliable signs that bacteria have moved in.
If none of these patterns apply and you’re within the first week of symptoms, you most likely have a viral cold that will resolve on its own.
Where the Pain Shows Up
You have four pairs of sinuses, and the location of your pain often reflects which ones are inflamed. The most commonly affected are the maxillary sinuses, which sit in your cheekbones just above your upper molars. Pressure there causes aching in the cheeks and can radiate into your upper teeth, mimicking a toothache. In fact, upper tooth pain with no obvious dental cause is one of the better predictors of a sinus infection.
The frontal sinuses sit in the lower forehead, and when they’re involved you’ll feel pressure or a headache centered above your eyebrows. The ethmoid sinuses are between your eyes, causing pain at the bridge of your nose. The sphenoid sinuses are deeper, behind the nose, and tend to produce a more diffuse headache at the back of the head. Pain that is noticeably worse on one side is particularly suggestive of a bacterial infection.
One thing worth knowing: pressing on your cheeks or forehead to check for tenderness is something doctors do during exams, but studies show it has limited predictive value. You can’t reliably confirm or rule out a sinus infection based on whether your face hurts when you push on it.
Mucus Color: Useful but Not Definitive
Yellow or green mucus gets a lot of attention as a sinus infection signal, and it does carry some diagnostic weight. Discolored discharge is one of the symptoms doctors look for, especially when it’s thick, purulent (pus-like), and drains predominantly from one nostril. But mucus color alone cannot tell you whether an infection is viral or bacterial. Bacteria can be present in your nasal passages without causing an actual infection, and viral colds frequently produce yellow or green mucus during the middle stages of illness.
The more reliable approach is to combine mucus color with duration and other symptoms. Green discharge on day 3 of a cold is normal. Green discharge on day 12, alongside worsening facial pressure and fatigue, tells a different story.
Sinus Infection vs. Allergies
Allergies and sinus infections can both cause congestion, a runny nose, and postnasal drip, but they feel quite different in a few key ways. The simplest distinction: allergies itch. Itchy, watery eyes, an itchy or scratchy throat, and frequent sneezing are hallmarks of allergic rhinitis. Sinus infections almost never cause itchiness.
Allergies also follow seasonal or environmental patterns. If your symptoms flare every spring or after spending time around cats, you’re dealing with an allergic response. Allergies don’t cause fever, and the nasal discharge tends to be clear and thin rather than thick and discolored. A sinus infection is more likely to produce facial pain, fatigue, reduced sense of smell, and that thick yellow or green discharge.
How Sinus Infections Look Different in Children
Children get sinus infections, but they don’t always describe their symptoms the way adults do. A child might not complain of facial pressure. Instead, the signs to watch for are a persistent cough (often worse at night from postnasal drip), nasal congestion that causes mouth breathing or snoring, and nasal discharge that stays yellow or green beyond the typical cold timeline. Bad breath that isn’t explained by poor dental hygiene can also be a clue, since trapped mucus and bacteria in the sinuses can produce a noticeable odor. Fever is more common in children with acute sinus infections than in adults.
When a Sinus Infection Becomes Serious
The vast majority of sinus infections are uncomfortable but not dangerous. However, because the sinuses are close to the eyes and brain, infection can occasionally spread to those areas. Seek immediate medical attention if you notice pain, swelling, or redness around one or both eyes, double vision or other vision changes, a stiff neck, confusion, or a very high fever. These symptoms suggest the infection may have moved beyond the sinuses and needs urgent treatment.
Do You Need Imaging or Testing?
For a straightforward sinus infection, the answer is almost always no. Medical guidelines from the American Academy of Otolaryngology specifically recommend against CT scans or other imaging for uncomplicated acute sinusitis. Doctors diagnose it based on your symptoms and their timeline. Imaging is reserved for cases where a complication is suspected (like those eye or neurological symptoms) or when symptoms have dragged on for 12 weeks or more, at which point chronic sinusitis is on the table and a CT scan or nasal endoscopy helps confirm the diagnosis and guide treatment.
Acute vs. Chronic Sinusitis
Acute sinusitis, even when bacterial, typically resolves within a few weeks with or without antibiotics. Chronic sinusitis is defined as symptoms lasting 12 weeks or longer. The symptoms are similar, including congestion, facial pressure, discolored discharge, and reduced sense of smell, but they tend to be less intense and more grinding than the acute version. Chronic sinusitis often involves underlying factors like nasal polyps, a deviated septum, or persistent inflammation rather than a single bacterial infection. If your symptoms have persisted for three months or more despite treatment, that’s a different condition requiring a different evaluation.