Sinus Infection Symptoms: How to Tell Viral Rhinosinusitis from a Bacterial Infection

Sinus infection symptoms can be uncomfortable and may include a blocked or runny nose, facial pressure, cough, headache, and reduced sense of smell. Most cases begin after a common cold and are caused by a virus. They usually improve without antibiotics.

A smaller number are caused by bacteria. The symptoms can overlap, so the most useful clues are how severe the illness is, how long it lasts, and whether it improves before getting worse again. No single symptom—including the color of nasal mucus—can reliably prove that an infection is bacterial.

The information below reflects clinical guidance from organizations including the Centers for Disease Control and Prevention, the American Academy of Otolaryngology–Head and Neck Surgery, and infectious disease guidelines.

Common sinus infection symptoms

Acute rhinosinusitis, often called a sinus infection, involves inflammation of the nose and sinus lining. Common symptoms include:

• Nasal congestion or blockage
• Clear, yellow, or green nasal drainage
• Mucus dripping down the throat
• Pressure, fullness, or pain around the cheeks, eyes, forehead, or nose
• Headache or facial discomfort that may worsen when bending forward
• Reduced or lost sense of smell
• Cough, especially at night
• Sore throat or bad breath
• Tiredness
• Fever, which is more common in some viral infections and bacterial cases than others

Adults and children may have similar symptoms, although children often have more cough, irritability, nasal drainage, or trouble sleeping. Facial pain is not always present, and its absence does not rule out sinus inflammation.

The main clinical clues: duration, severity, and symptom pattern

Doctors generally distinguish viral rhinosinusitis from suspected bacterial infection using three clinical patterns.

1. Symptoms lasting fewer than 10 days and gradually improving

A viral infection is more likely when symptoms have been present for less than 10 days and are slowly getting better. A cold may cause substantial congestion, thick mucus, cough, and facial pressure for several days. These symptoms can sometimes linger for up to two weeks, but the overall direction should be improvement.

Antibiotics do not treat viruses. Taking them when they are not needed can cause side effects, contribute to antibiotic resistance, and make future infections harder to treat.

2. Severe symptoms at the beginning

Bacterial infection becomes more likely when symptoms are severe from the start. Clinical guidance commonly describes this pattern as:

• A fever of 39°C (102°F) or higher, together with
• Purulent nasal discharge, meaning thick, cloudy, or pus-like drainage, and/or significant facial pain
• Symptoms lasting for at least three to four consecutive days

A high fever alone does not establish a bacterial sinus infection. Similarly, thick or discolored mucus alone is not enough. The combination of high fever, substantial nasal discharge, and notable facial pain is more concerning for bacterial disease than any one of these findings by itself.

3. Symptoms that improve, then worsen

A “double-worsening” pattern is another important clinical marker. This occurs when cold-like symptoms begin to improve, then become noticeably worse after about five to six days. New or worsening symptoms may include:

• Increasing facial pain or pressure
• New or returning fever
• More severe nasal blockage
• Increasing nasal discharge
• Worsening cough or fatigue

This pattern can suggest a bacterial infection developing after an initial viral illness. It does not guarantee that antibiotics are needed, but it is a good reason to speak to a doctor.

Why green or yellow mucus does not prove a bacterial infection

Many people assume that green or yellow nasal mucus means bacteria are present. In reality, mucus can change color during a normal viral infection as immune cells and other substances collect in the nasal passages. Colored mucus is therefore common in both viral and bacterial rhinosinusitis.

The color, thickness, or unpleasant smell of mucus should be considered alongside the full illness pattern. Duration, high fever, severe facial pain, and worsening after initial improvement are generally more useful than mucus color alone.

Viral and bacterial symptoms can overlap

It is not always possible to tell the cause at home. A viral infection may cause considerable facial pressure, headache, fatigue, and thick drainage. A bacterial infection may begin with relatively mild symptoms. Also, allergies, migraine, dental problems, nasal polyps, and other conditions can cause congestion or facial pressure without a sinus infection.

A doctor may ask:

• When did the symptoms begin?
• Have they improved, stayed the same, or worsened?
• Was there a period of improvement followed by a setback?
• Is there a high or persistent fever?
• Is the pain mainly on one side, or is it severe?
• Are there dental symptoms, allergies, asthma, or previous sinus problems?
• Are there vision changes, swelling, or other unusual symptoms?

In uncomplicated cases, imaging and sinus cultures are usually not needed. A healthcare professional can often make a diagnosis based on the history and examination. Imaging may be considered when symptoms are recurrent, unusually severe, prolonged, or suggest a complication or another diagnosis.

What you can do for symptom relief

For many uncomplicated viral cases, treatment focuses on comfort while the body clears the infection. Helpful measures may include:

• Drinking fluids according to your usual health needs
• Resting and avoiding smoke or other nasal irritants
• Using saline nasal spray or a saline rinse with distilled, sterile, or previously boiled and cooled water
• Applying a warm compress to the face
• Using a humidifier, cleaned regularly
• Taking acetaminophen or ibuprofen for pain or fever if these medicines are safe for you

Some decongestants may provide short-term relief, but they are not suitable for everyone. Nasal decongestant sprays should generally not be used for more than three days because they can cause rebound congestion. People with high blood pressure, heart disease, glaucoma, pregnancy, kidney disease, or certain medication interactions should ask a healthcare professional before using decongestants.

Do not use leftover antibiotics or someone else’s prescription. If bacterial infection is suspected, a doctor can decide whether antibiotics are appropriate, which medicine is suitable, and how long it should be taken.

If you are unsure what your symptoms may indicate, you might consider a free, online symptom check, using the doctor approved Ubie Symptom Checker. It can help organize symptoms and suggest what type of medical care may be appropriate, but it does not replace an examination or diagnosis from a qualified clinician.

When to speak to a doctor

Speak to a doctor if symptoms:

• Last more than 10 days without improvement
• Are severe, including high fever with significant facial pain or thick nasal discharge
• Improve and then clearly worsen
• Keep returning or interfere substantially with sleep, work, or daily activities
• Occur in a young child, older adult, or someone with a weakened immune system
• Include severe one-sided facial or tooth pain

Seek urgent medical care for symptoms that could signal a serious complication, such as swelling or redness around an eye, vision changes, severe headache unlike usual, confusion, stiff neck, repeated vomiting, fainting, trouble breathing, or rapidly worsening illness. Speak to a doctor promptly about anything that could be life threatening or serious.

Most sinus infection symptoms are caused by inflammation from a virus and settle with time and supportive care. The strongest clues for possible bacterial infection are severe symptoms from the beginning, symptoms lasting beyond 10 days without improvement, or symptoms that worsen after an initial improvement. When in doubt, a healthcare professional can assess the pattern and help you choose the safest next step.