The hallmark signs of a sinus infection are thick, discolored nasal discharge combined with facial pain or pressure and nasal congestion that won’t let up. Most sinus infections start as a common cold, and the key question isn’t whether you have symptoms but how long they’ve lasted and whether they’re getting worse. Here’s what to look for and what each symptom pattern means.
The Core Symptoms
A sinus infection, or sinusitis, produces a recognizable cluster of symptoms. The most common include:
- Thick nasal discharge that’s yellow, green, or cloudy, sometimes draining down the back of your throat (postnasal drip)
- Nasal congestion that makes it hard to breathe through one or both nostrils
- Facial pain or pressure concentrated around your cheeks, forehead, or between your eyes, often worse when you bend forward
- Reduced sense of smell and taste
- Fever, typically low-grade but sometimes reaching 102°F or higher
- Fatigue and a general feeling of being unwell
Several less obvious symptoms also point to a sinus infection. A cough that worsens at night is common, caused by mucus dripping down the back of your throat while you lie down. Bad breath is another frequent sign, since bacteria thrive in stagnant mucus. Some people also notice ear pressure or fullness, a sore throat from postnasal drip, or swelling around the eyes that’s most noticeable in the morning.
Upper Tooth Pain as a Sinus Symptom
Pain in your upper back teeth can be a sinus infection in disguise. Your maxillary sinuses (the ones behind your cheekbones) sit directly above the roots of your upper molars, and when those sinuses swell with infection, the pressure pushes down on the tooth roots. A telling clue: the tenderness affects multiple upper teeth at once and gets worse when you change head position, like bending over to tie your shoes.
The relationship works in both directions. More than 40% of maxillary sinus infections actually originate from a dental infection rather than a cold. If your sinus symptoms are concentrated on one side of your face and you’ve had recent dental work or a toothache, a dental source is worth investigating.
Viral vs. Bacterial: How to Tell the Difference
Most sinus infections start as viral infections and will clear on their own. The critical distinction is whether a bacterial infection has developed, because that’s when antibiotics become necessary. Three patterns suggest a bacterial sinus infection:
- Symptoms lasting 10 days or more with no improvement. A viral infection typically starts improving by day 7 to 10.
- Severe onset: a fever of 102°F or higher along with facial pain and discolored nasal discharge lasting three to four consecutive days.
- “Double sickening”: you start to feel better after four to seven days, then suddenly get worse again. This rebound pattern is one of the most reliable indicators of a bacterial infection taking hold.
The color of your mucus alone doesn’t confirm a bacterial infection. Both viral and bacterial sinus infections can produce green or yellow discharge. What matters more is the timeline and trajectory of your symptoms.
One Side vs. Both Sides
Pay attention to whether your symptoms are concentrated on one side of your face. Unilateral pain, meaning pain that’s clearly worse on the left or the right, with discharge coming primarily from one nostril, is a stronger indicator of a bacterial infection than symptoms spread evenly across both sides. Tenderness when pressing on the cheekbone on just one side also raises the likelihood. Bilateral symptoms are more typical of a viral upper respiratory infection or allergies.
When Symptoms Last Longer Than 12 Weeks
If your symptoms persist for 12 weeks or longer, the condition is classified as chronic sinusitis. Chronic sinusitis doesn’t always feel as intense as an acute infection. The fever and sharp facial pain may fade, replaced by a persistent low-level congestion, postnasal drip, reduced smell, and facial pressure that never fully resolves. Some people live with it for months before recognizing it as something beyond “always being a little stuffy.”
Chronic sinusitis has different underlying causes than a one-time infection. Nasal polyps, a deviated septum, allergies, and recurring inflammation all play a role, and treatment focuses on managing those root causes rather than simply clearing an infection.
Signs in Children
Sinus infections look different in kids, especially young children who can’t describe what they’re feeling. In children under five, headaches are uncommon. Instead, the main signs are a runny nose lasting longer than 7 to 10 days (with thick green or yellow discharge), a nighttime cough, occasional daytime cough, and swelling around the eyes. Irritability and fatigue often stand in for the “I feel awful” that an adult would report.
Older children present more like adults, with headaches, facial discomfort, bad breath, sore throat, and fever joining the mix. The 7 to 10 day rule still applies: a cold that refuses to improve past that window, or one that seems to get better and then rebounds, is the clearest signal that something beyond a virus is going on.
Symptoms That Need Immediate Attention
In rare cases, a sinus infection can spread to nearby structures, particularly the eye socket or the brain. These complications develop quickly and require emergency care. Warning signs include swelling around the eye severe enough to limit how far you can open it, a bulging eye, changes in vision or double vision, a sudden severe headache unlike your usual sinus pressure, high fever with a stiff neck, or confusion. Infections originating in the frontal sinuses (behind the forehead) carry a higher risk of spreading toward the brain, so intense forehead pain with high fever deserves prompt evaluation.
What a Doctor Looks For
If you see a doctor for suspected sinusitis, the exam is straightforward. They’ll press on your cheeks and forehead to check for tenderness, look inside your nose for swollen, reddened tissue and the color and location of any discharge, and check the back of your throat for signs of mucus draining downward. In some cases, a small lighted scope provides a closer view of where the drainage is originating. Imaging like a CT scan is typically reserved for chronic cases or when complications are suspected, not for a standard acute infection.
The diagnosis is primarily based on your symptoms and their timeline rather than any single test. Knowing exactly how long you’ve been sick, whether you had a cold first, and whether your symptoms improved before worsening again gives your doctor the most useful information.