The hallmark symptoms of a sinus infection are thick nasal discharge, nasal congestion, facial pain or pressure, and a reduced sense of smell. These four symptoms are considered the cardinal signs, and experiencing at least two of them for more than 10 days points toward a sinus infection rather than a regular cold. Nearly 29 million adults in the U.S. are diagnosed with sinusitis each year, making it one of the most common reasons people seek medical care.
The Core Symptoms
Most sinus infections share the same cluster of symptoms, though the severity varies. Nasal congestion that makes it hard to breathe through one or both nostrils is usually the most noticeable. Thick nasal discharge, often dripping down the back of the throat (postnasal drip), frequently accompanies it. This drainage can trigger a sore throat, bad breath, and a cough that tends to be worse at night when you’re lying down.
Facial pain or pressure is the symptom most people associate with a sinus infection, and the location of that pain depends on which sinuses are involved:
- Cheek sinuses (maxillary): Pain below the eyes and across the cheeks, sometimes mimicking a toothache in the upper jaw.
- Forehead sinuses (frontal): A headache concentrated across the forehead.
- Between-the-eyes sinuses (ethmoid): Pain behind and between the eyes, sometimes described as a splitting headache, often with tearing.
- Deep sinuses (sphenoid): A vague pain that can be felt in the front or back of the head without a clear focal point.
A reduced or lost sense of smell rounds out the core symptoms. You may also notice that food tastes bland, since smell and taste are closely linked. Low-grade fever, fatigue, and a general feeling of being unwell are common but not universal.
How to Tell It Apart From a Cold
Colds and sinus infections start the same way, and most sinus infections actually begin as viral colds. The key difference is timing. A typical cold improves within 7 to 10 days. If your symptoms persist without any improvement past the 10-day mark, the infection has likely settled into the sinuses.
There’s also a pattern called “double sickening.” You start feeling better after a few days of cold symptoms, then suddenly get worse again, with returning congestion, worsening facial pressure, or a new fever. This rebound is a strong signal that a bacterial sinus infection has developed on top of the original viral illness.
A more severe presentation can appear earlier. Fever above 102°F, intense one-sided facial pain, and thick discolored discharge lasting 3 or more consecutive days suggest a bacterial infection even before the 10-day window.
What Mucus Color Actually Means
Yellow or green mucus is widely believed to signal a bacterial infection, but this is a myth that persists even among some clinicians. Both viral and bacterial infections cause the same color changes in nasal mucus. The greenish tint comes from enzymes released by white blood cells fighting the infection, regardless of whether bacteria are involved. Mucus color alone is not a reliable way to distinguish between a viral cold and a bacterial sinus infection. Duration and symptom pattern matter far more.
Symptoms in Children
Sinus infections look different in kids, especially younger ones. Children under five rarely complain of headaches or facial pressure the way adults do. Instead, the main signs are a runny nose lasting longer than 10 days, thick green or yellow discharge (though it can also be clear), and a cough that’s worse at night. Swelling around the eyes, particularly in the morning, is another telltale sign in children.
Older children and teenagers present more like adults, with headaches, facial discomfort, postnasal drip, and bad breath. In any age group, a cold that simply refuses to get better after 10 days warrants a closer look.
Acute vs. Chronic Sinus Infections
An acute sinus infection typically resolves within four weeks. Most people deal with a rough week or two and then gradually improve, whether the cause is viral or bacterial.
Chronic sinusitis is a different condition. It’s defined by the presence of at least two of the four cardinal symptoms, facial pain, reduced smell, nasal drainage, and nasal obstruction, persisting for 12 consecutive weeks or longer. Chronic sinusitis often involves ongoing inflammation rather than active infection, and it tends to cause a more muted, grinding discomfort rather than the acute, sharp pressure of a short-term infection. Nasal polyps, allergies, and structural issues in the nasal passages are common contributors.
Symptoms That Need Immediate Attention
Sinus infections rarely become dangerous, but when they do, the infection can spread to nearby structures like the eye socket or the membranes surrounding the brain. Seek care right away if you notice any of the following:
- Swelling or redness around the eyes
- Double vision or other vision changes
- High fever
- Stiff neck
- Confusion
These symptoms are uncommon but can indicate spread to the eye socket or early meningitis, both of which require prompt treatment.