A sinus infection typically causes a combination of facial pain or pressure, thick nasal discharge, a stuffy nose, and a reduced sense of smell. These four symptoms are considered the cardinal signs, and having at least two of them is the standard benchmark doctors use for diagnosis. Most sinus infections start as a viral cold and resolve on their own, but recognizing the full range of symptoms helps you gauge what’s going on and whether something more serious might be developing.
The Four Cardinal Symptoms
Doctors evaluate sinus infections based on four core symptoms: facial pain or pressure, nasal drainage, nasal obstruction (stuffiness), and a decreased or lost sense of smell. You don’t need all four. Having at least two is enough to point toward sinusitis, especially when they’ve persisted for more than a week or so.
Facial pain tends to be the symptom people notice most. It often centers around the cheeks, forehead, or the bridge of the nose, depending on which sinus cavities are inflamed. The pain can radiate to your upper teeth, which catches many people off guard. A sinus-related toothache typically affects several upper teeth at once rather than a single tooth, and it often worsens when you bend forward.
Nasal discharge is usually thick and discolored, ranging from yellow to green. You may notice it dripping from your nose or, more commonly, sliding down the back of your throat (postnasal drip), which creates a persistent feeling of mucus in your throat and can trigger a cough or a sore, irritated feeling.
Symptoms You Might Not Expect
Beyond the core four, sinus infections produce a handful of less obvious symptoms that people don’t always connect to their sinuses. A persistent cough, especially one that worsens at night, is common and usually caused by postnasal drip irritating the throat. Bad breath is another frequent companion, driven by bacteria-laden mucus draining into the back of the mouth.
Some people experience phantom smells during or after a sinus infection. This means detecting odors that aren’t actually present, often described as the smell of burning rubber, garbage, chemicals, or something metallic. Sinus infections are one of the recognized triggers for this phenomenon. A distorted sense of smell, where real odors smell different than they should, can also occur. Both typically resolve as the infection clears.
Ear pressure or fullness is common too, since the sinuses and ears share drainage pathways. Fatigue often accompanies a sinus infection, partly from the immune response and partly from poor sleep caused by congestion.
Where It Hurts Depends on Which Sinuses Are Affected
You have four pairs of sinus cavities, and the location of your pain offers a clue about which ones are inflamed. The maxillary sinuses sit behind your cheekbones, and when they’re infected, you feel pressure in your cheeks, upper teeth, or jaw. This is the most common type.
The frontal sinuses are behind your forehead. Infection here causes a headache concentrated above the eyebrows that can feel worse in the morning. The ethmoid sinuses sit between your eyes, near the bridge of your nose, and produce pain or pressure in that area. The sphenoid sinuses are deeper, behind the ethmoid sinuses, and can cause pain at the top of the head or behind the eyes, though sphenoid sinusitis is relatively uncommon.
Pain that is noticeably worse on one side of the face is more suggestive of a bacterial infection than a viral one.
Viral vs. Bacterial: How to Tell the Difference
The vast majority of sinus infections are viral, meaning they’re caused by the same viruses responsible for the common cold. A viral sinus infection typically improves within 7 to 10 days. Antibiotics won’t help.
A bacterial sinus infection is suspected when symptoms last more than 10 days without improvement, or when symptoms initially improve and then suddenly get worse again. Another pattern that suggests bacteria: severe symptoms from the start, including a high fever (102°F or above) along with thick, discolored discharge lasting at least 3 to 4 consecutive days. The color of your mucus alone isn’t a reliable indicator. Yellow or green discharge happens in both viral and bacterial infections as your immune system responds.
Acute vs. Chronic Sinus Infections
An acute sinus infection lasts less than four weeks and is usually a one-time event triggered by a cold. Subacute infections fall in the 4 to 12 week range. Chronic sinusitis is defined as having at least two of the four cardinal symptoms for 12 consecutive weeks or longer. Chronic sinusitis is a different condition in many respects. It’s often driven by ongoing inflammation, nasal polyps, or structural issues rather than a single infection, and it requires a different treatment approach.
People with chronic sinusitis tend to have less dramatic symptoms than those with acute infections. The pain may be more of a dull, constant pressure than a sharp ache, and fever is uncommon. Loss of smell, on the other hand, is more prominent and sometimes persists even between flare-ups.
Symptoms in Children
Children get sinus infections too, but their symptoms can look different. Young kids rarely complain of facial pressure the way adults do. Instead, the most telling signs are a runny nose with thick yellow or green discharge lasting more than 10 days, a cough that persists (particularly at night), nasal congestion with mouth breathing or snoring, and sometimes a low-grade fever. Irritability and fatigue are common in younger children who can’t articulate what they’re feeling.
Bad breath in a child who otherwise has good dental hygiene is a surprisingly reliable clue. Headache and facial pain become more common in older children and teenagers, whose sinus cavities are more fully developed.
Red Flag Symptoms That Need Immediate Attention
Most sinus infections are uncomfortable but not dangerous. However, because the sinuses sit close to the eyes and brain, infection can occasionally spread to surrounding structures. Seek immediate medical care if you notice any of the following: swelling, redness, or pain around the eyes; double vision or other vision changes; a high fever that isn’t responding to treatment; confusion; or a stiff neck. These symptoms can indicate that the infection has moved beyond the sinuses and needs urgent treatment.