What is a sinus infection?
The sinuses are air-filled spaces in the bones of the face (cheeks, forehead, between the eyes and behind the nose) lined with mucous membrane. A cold, allergy or structural problem can swell the lining and block drainage, so mucus builds up and becomes infected. The result is acute sinusitis (lasting up to 4 weeks), recurrent sinusitis, or chronic sinusitis (12 weeks or more). See home remedies for sinus infection and sinus pressure relief.
Main symptoms
- Nasal congestion or blockage; difficulty breathing through the nose.
- Thick yellow or green nasal discharge and drainage down the throat (postnasal drip). See postnasal drip.
- Facial pain, pressure or fullness around the cheeks, eyes or forehead, worse when bending forward.
- Reduced or lost sense of smell and taste. See loss of smell.
- Headache, often over the eyes or forehead. See sinus headache.
- Toothache in the upper teeth.
- Cough, worse at night, sore throat and bad breath.
- Ear pressure, fatigue and low-grade fever.
Viral or bacterial?
Colour of mucus does not reliably tell the difference: green or yellow mucus is common in viral colds. Duration and pattern are more helpful.
- Viral (most common): symptoms peak around days 3–5 and improve by 7–10 days, typically after a cold.
- Bacterial is more likely if: symptoms last more than 10 days without improvement; you have severe symptoms (fever above 39 °C with purulent discharge and facial pain) for 3–4 consecutive days at the start; or you improve and then get worse again (“double worsening”).
- Fungal and allergic sinusitis are less common and need specialist assessment.
Chronic sinusitis symptoms
- Symptoms lasting 12 weeks or more: blockage, discharge, facial pressure and reduced smell.
- Causes include nasal polyps, deviated septum, allergies, asthma, immune problems and repeated infections. See nasal polyps.
- Diagnosis involves nasal endoscopy and often a CT scan.
- Treatment: saline rinses, steroid nasal sprays, treating allergy, courses of medicine and, if needed, sinus surgery.
What helps at home
- Rinse your nose with saline (use distilled or boiled and cooled water). See neti pot sinus rinse.
- Inhale steam or use a warm compress over the face.
- Drink plenty of fluids and rest.
- Use a humidifier and avoid smoke.
- Take paracetamol or ibuprofen for pain and fever if suitable.
- Use a steroid nasal spray (such as fluticasone) as advised; decongestant sprays for no more than 3 days.
- Sleep with your head slightly raised.
Medical treatment
- Watchful waiting is often the first step for mild acute sinusitis.
- Antibiotics (usually amoxicillin-based) for suspected bacterial infection, severe symptoms or high-risk patients.
- Nasal steroid sprays to reduce swelling.
- Antihistamines if allergy contributes.
- Oral steroids for polyps or severe inflammation, under supervision.
- Surgery (functional endoscopic sinus surgery) for chronic or complicated cases when medicine fails.
- Antibiotics do not help viral sinusitis and have side effects.
Prevention
- Wash hands regularly and avoid close contact when you have a cold.
- Manage allergies and keep nasal passages moist.
- Do not smoke and avoid pollution and smoke exposure.
- Stay hydrated and avoid flying with a severe cold if possible.
- Get vaccinated against flu and COVID-19 as advised.
- Treat structural problems such as polyps or a deviated septum.
Children and sinus infections
Children get many colds and their sinuses are still developing, so true sinusitis is less common than parents think. Consider it if a cold lasts more than 10 days without improvement, or with high fever and purulent discharge. Seek urgent help for eye swelling, severe headache or lethargy. Avoid giving cold medicines to young children.
When to see a doctor
- Symptoms lasting more than 10 days, or worsening after initial improvement.
- High fever, severe facial pain or severe headache.
- Symptoms returning repeatedly.
- Swelling or redness around an eye, vision changes, confusion or stiff neck: urgent.
- Immune problems, diabetes or recent sinus surgery.
- Persistent one-sided symptoms, nosebleeds or loss of smell.
- Facial pain with tooth pain on one side.
Three common situations
A cold that turns into facial pressure and green mucus on day 4: usually viral; rinse, fluids and wait.
Ten days of thick discharge and cheek pain without improvement: see a doctor; possible bacterial sinusitis.
Facial pain with an eye that is swollen and red: urgent medical attention.
Key points to remember
Sinus infections cause congestion, facial pressure, thick discharge and reduced smell. Most are viral and settle within 10 days with simple care. See a doctor for symptoms lasting longer, worsening or severe, and urgently for eye or neurological signs. Our ENT team can assess persistent sinus problems.
This guide is for general information and does not replace an examination by your own doctor or ENT specialist.
Questions about sinus infection symptoms
These answers are general information and do not replace an examination or individual medical advice.
What are the signs of a sinus infection?
Nasal congestion, thick discharge, facial pain or pressure, reduced smell, headache and cough.
How can I tell if it is bacterial?
Symptoms lasting more than 10 days, severe fever and pain early on, or getting worse after improving.
Do I need antibiotics?
Usually not; most sinus infections are viral and resolve without them.
How long does a sinus infection last?
Typically 7–10 days; chronic sinusitis lasts 12 weeks or more.
Is green mucus a sign of bacterial infection?
Not necessarily; colour is common in viral colds too.
When is a sinus infection an emergency?
With eye swelling or redness, vision changes, severe headache, stiff neck or confusion.
Sources
This guide is for general information and does not replace medical advice. How a problem is diagnosed and treated depends on your examination and medical history. If you think you have an emergency, contact your local emergency services.