The hallmark symptoms of a sinus infection are thick nasal discharge, a blocked or stuffy nose, and pain or pressure in the face. Most sinus infections start as a common cold, and the transition from one to the other can be hard to spot. The key difference is timing: symptoms that persist beyond 10 days without improving, or that get worse after initially getting better, point toward a sinus infection rather than a simple cold.
The Four Cardinal Symptoms
Sinus infections produce four core symptoms that overlap in various combinations:
- Nasal discharge: Thick, discolored mucus draining from the nose or down the back of the throat. It may be yellow, green, or grayish.
- Nasal obstruction: A blocked or congested feeling on one or both sides that makes breathing through the nose difficult.
- Facial pain or pressure: A deep ache or fullness around the cheeks, forehead, or between the eyes. Bending forward often makes it worse.
- Reduced sense of smell: Partial or complete loss of smell, which also dulls your sense of taste. Up to 83% of people with chronic sinus infections experience some degree of smell loss, caused by inflammation blocking odor molecules from reaching the nerve endings high inside the nose.
You don’t need all four to have a sinus infection. A diagnosis typically requires at least two of these symptoms persisting for a meaningful stretch of time.
Symptoms Most People Don’t Expect
Beyond the classic stuffy nose and facial pressure, sinus infections cause a handful of symptoms that can be confusing because they don’t seem related to your sinuses at all.
Toothache. The maxillary sinuses sit directly above the roots of your upper back teeth. When those sinuses fill with infected mucus, the pressure pushes down on the tooth roots, creating a dull ache across several upper teeth at once. About 10% of maxillary sinus infections actually originate from a dental problem, so pain that’s isolated to a single tooth is worth mentioning to your dentist.
Bad breath. Infected mucus draining down the back of the throat produces a persistent foul smell that brushing and mouthwash won’t fix. This is especially common in chronic cases.
Fatigue. Your immune system is working overtime, and the combination of poor sleep from congestion and general inflammation leaves many people feeling wiped out. Fever and general malaise are more common in acute infections.
Cough. Postnasal drip, the constant trickle of mucus down the throat, triggers a cough that tends to be worse at night when you lie down.
How to Tell It Apart From a Cold
A standard cold and a sinus infection share nearly identical early symptoms. The distinction comes down to two patterns.
The first is duration. Cold symptoms typically peak around days 3 to 5 and then gradually improve. If your congestion, discharge, and facial pressure are no better after 10 days, that persistence suggests a bacterial sinus infection has developed on top of the original viral illness.
The second pattern is called “double sickening.” You start feeling better after the first few days of a cold, then between days 5 and 10, your symptoms come roaring back or noticeably worsen. A new fever, worsening facial pain, or a fresh wave of thick nasal discharge during this window is a strong signal that bacteria have taken hold.
One common misconception: green or yellow mucus does not automatically mean you have a bacterial infection. Both viruses and bacteria change the color and texture of nasal mucus. Color alone isn’t a reliable way to distinguish between the two, even though this myth persists in some medical circles.
Acute vs. Chronic Symptoms
An acute sinus infection lasts less than four weeks and usually resolves on its own or with a short course of treatment. Symptoms tend to be more intense: sharper facial pain, fever, and visibly discolored discharge.
Chronic sinusitis is defined as symptoms lasting 12 consecutive weeks or longer. The experience is different. Pain may be less dramatic but more grinding, a constant low-level pressure or fullness that becomes your new normal. The dominant complaints shift toward persistent postnasal drip, bad breath, a dulled sense of smell and taste, and fatigue. People with chronic sinusitis often describe feeling “foggy” rather than acutely sick. Diagnosis requires not just symptoms but objective evidence of inflammation, usually confirmed through a nasal exam or CT scan.
How Symptoms Look Different in Children
Children get sinus infections too, but they don’t always describe symptoms the way adults do. In kids, the telltale signs are a runny nose and daytime cough lasting more than 10 days without improvement. Facial pain is less commonly reported, partly because younger children can’t always articulate it. Bad breath alongside cold symptoms is another clue, though it can also come from a sore throat or inconsistent tooth brushing. The “double sickening” pattern applies to children as well: a cold that seems to improve and then gets worse again warrants a closer look.
Warning Signs of Serious Complications
Sinus infections rarely become dangerous, but the sinuses sit close to the eyes and brain, which means infection can occasionally spread to those areas. The most common serious complication involves the eye socket, since the thin bone separating the sinuses from the orbit offers little resistance to spreading infection.
Early signs of orbital involvement include swelling and redness around the eye. More advanced infection causes the eye to bulge forward, pain with eye movement, and restricted ability to look in certain directions. Over 80% of patients with orbital complications report significant eye pain. Changes in vision or color perception, particularly difficulty distinguishing red or green, are late warning signs that pressure is building dangerously inside the eye socket. This type of complication can cause permanent vision loss if not treated within hours.
Seek emergency care if you develop swelling around the eye, changes in vision, a severe headache unlike anything you’ve experienced before, a high fever that won’t break, or a stiff neck alongside sinus symptoms. These situations are uncommon but require immediate attention.