The three hallmark symptoms of a sinus infection are thick, discolored nasal discharge combined with nasal congestion and facial pain or pressure. Most sinus infections start as a common cold, and only about 0.5% to 2% of viral upper respiratory infections progress to a bacterial sinus infection. Knowing what to look for helps you tell the difference between a cold that’s running its course and an infection that needs attention.
The Core Symptoms
A sinus infection, also called sinusitis, produces a recognizable cluster of symptoms. Thick green or yellow mucus draining from the nose or down the back of the throat is the most distinctive sign. This discharge is often accompanied by a stuffy nose that makes breathing through one or both nostrils difficult, along with a feeling of fullness, pressure, or pain across the face.
Beyond those three primary symptoms, sinus infections commonly cause:
- Reduced or lost sense of smell. Swollen sinus tissue blocks odor molecules from reaching smell receptors. In chronic cases, studies using standardized smell tests have found that up to 78% of patients have some degree of smell loss.
- Fever. More common in acute infections and less typical once sinusitis becomes chronic.
- Postnasal drip. Mucus draining down the throat can trigger a persistent cough, a sore throat, or a raspy voice, especially at night.
- Fatigue. Your body is fighting an infection, and the combination of poor sleep from congestion and an active immune response leaves you drained.
- Bad breath. Stagnant, infected mucus sitting in your sinuses and dripping down your throat produces a noticeable odor.
Where the Pain Shows Up
The location of your facial pain depends on which sinuses are affected. You have four pairs of sinuses, and each one sends pain to a slightly different spot.
Infection in the maxillary sinuses, the large ones behind your cheekbones, causes pain across the cheeks and upper jaw. Because the roots of your upper back teeth sit very close to (or even extend into) the maxillary sinus cavity, a sinus infection here can feel exactly like a toothache. That upper-tooth pain is one of the most common secondary symptoms and catches many people off guard.
Frontal sinus infections produce pain and tenderness across the forehead, particularly near the inner edge of the eyebrow where the bone is thinnest. Ethmoid sinuses, located between your eyes, cause pain around or behind the eyes. Sphenoid sinusitis is the least common type and tends to cause a deep ache at the top of the head, though the pain can radiate to the temples or feel like it’s spread across the whole head.
How to Tell It Apart From a Cold
Every sinus infection starts with inflammation, and most of that inflammation begins with a virus, the same one giving you a cold. The tricky part is figuring out when a cold has crossed the line into a sinus infection that might be bacterial.
Two patterns suggest a bacterial infection rather than a lingering cold. The first is persistence: nasal symptoms and cough that last 10 days or longer without improving. A typical cold peaks around days three to five and then gradually gets better. If you’re at day 10 and things are no better, that timeline alone is a meaningful signal.
The second pattern is called “double worsening.” You start to feel better after a few days of cold symptoms, then your nasal congestion, discharge, or fever suddenly gets substantially worse again. That rebound suggests bacteria have taken hold in sinuses that were already inflamed and poorly draining from the initial virus.
Symptoms in Children
Children get sinus infections too, but their symptoms look a bit different depending on age. Younger children rarely complain of headaches. Instead, the giveaway signs are a runny nose lasting longer than seven to 10 days (often with thick green or yellow discharge), a nighttime cough, and swelling around the eyes. Some children also develop a daytime cough, though it tends to be occasional rather than constant.
Older children and teenagers present more like adults, with headaches, facial discomfort, postnasal drip, sore throat, and bad breath. Eye swelling is often more noticeable in the morning after a night of lying flat, which allows fluid to pool around the sinuses. Because young children can’t always describe pressure or pain, parents often notice irritability, poor appetite, or mouth breathing as the first clues.
Acute vs. Chronic Sinusitis
Acute sinusitis lasts less than four weeks and is the type most people experience after a cold. Symptoms tend to be more intense, with higher fevers and sharper facial pain, but they resolve relatively quickly, either on their own or with treatment.
Chronic sinusitis is defined as symptoms persisting for 12 weeks or longer. The pain and pressure are usually duller and more constant rather than sharp, and fever is less common. Congestion, postnasal drip, and reduced smell become the dominant daily complaints. Chronic sinusitis is a different condition in many ways. It involves ongoing mucosal inflammation rather than a single infection, and it often requires a different treatment approach than a simple course of antibiotics.
Fungal Sinus Infections
Most sinus infections are viral or bacterial, but fungal sinusitis exists and presents somewhat differently. The most common non-invasive form is a fungus ball, which affects the maxillary sinus in about 94% of cases and produces cheesy, clay-like mucus visible on examination. Allergic fungal sinusitis tends to affect younger adults in their 20s and 30s, often those with a history of allergies or asthma, and causes significant nasal polyps along with dark, rubbery nasal casts.
Invasive fungal sinusitis is rare but serious, occurring almost exclusively in people with severely weakened immune systems. It can cause symptoms beyond typical sinusitis: numbness in the face, eye swelling, vision changes, personality or behavioral changes, and blackened tissue inside the nose. This form progresses rapidly and requires emergency treatment.
Symptoms That Signal a Serious Complication
Sinus infections very rarely spread to the eyes or brain, but the sinuses sit close to both. Seek immediate medical care if you notice swelling or redness around one or both eyes, double vision or other vision changes, a severe headache that feels different from sinus pressure, swelling of the forehead, a stiff neck, confusion, or a high fever. These symptoms can indicate that the infection has spread beyond the sinuses into the eye socket or toward the brain, both of which need urgent treatment.