Sinusitis
Almost always viral — and almost always given antibiotics anyway
What it is
Sinusitis is inflammation of the lining of the sinuses, producing facial pain and pressure, a blocked or runny nose, and a reduced sense of smell. ACUTE sinusitis is overwhelmingly VIRAL — it is, in most cases, what a common cold does to your sinuses — and it resolves on its own. CHRONIC sinusitis, lasting more than twelve weeks, is a different disease: it is an inflammatory condition rather than an infection, it is frequently associated with allergy and with nasal polyps, and it is treated quite differently.
Why it matters
Because acute sinusitis is one of the largest single drivers of unnecessary antibiotic prescribing in the world, and the reason is entirely understandable: it hurts, it goes on for a week, the mucus turns green, and green mucus feels like infection. It is not. GREEN OR YELLOW MUCUS DOES NOT MEAN BACTERIA — the colour comes from enzymes released by your own immune cells and it appears in ordinary viral colds. Most people given antibiotics for acute sinusitis would have got better at the same rate without them, and they carry the side effects and contribute to resistance for nothing. Meanwhile the treatments that DO help — nasal steroids, saline irrigation, time — are perceived as doing nothing because they are not a prescription.
What BioSignal knows about treating this
What works for Sinusitis
BioSignal’s clinical summary, most important first.
- MOST ACUTE SINUSITIS NEEDS NO ANTIBIOTICS — it is viral, and it resolves. If antibiotics are not offered, that is likely to be correct medicine rather than neglect, and it is worth knowing that before you ask for them
- GREEN MUCUS IS NOT EVIDENCE OF BACTERIA — the colour comes from your own immune cells' enzymes and occurs in ordinary viral colds. It is the single most common reason people demand antibiotics they do not need
- SALINE NASAL IRRIGATION — genuinely helpful, cheap, and consistently under-used because it does not feel like treatment
- INTRANASAL CORTICOSTEROID SPRAY — the best-evidenced treatment for both acute and chronic sinusitis. It must be used correctly (aim away from the septum) and it takes days to work, which is why people abandon it
- Analgesia, decongestants for a few days only (rebound congestion follows longer use), and time
- Antibiotics ONLY where the features above suggest bacterial infection — persistent beyond ten days, severe from the outset, or double-worsening
- For CHRONIC sinusitis: treat the allergy, continue nasal steroids, and get referred — this is a different disease and 'another course of antibiotics' is not the answer
- GO TO AN EMERGENCY DEPARTMENT for swelling around the eye, vision change, severe headache, or confusion — orbital and intracranial complications are rare and are sight- and life-threatening
Signal Records relevant to this condition
Interventions and contributing factors — some of these records describe a cause rather than a cure. The rating shown is BioSignal’s confidence in that Signal Record, not a claim about how well it treats this condition. Open any of them for the full evidence.
- Vitamin CHigh confidence
Does not prevent colds — one of the best-tested negatives in nutrition. Shortens them slightly, but only if you were already taking it. Megadoses are mostly excreted: absorption saturates around 200 mg/day. Genuinely useful for iron absorption, and genuinely essential — scurvy is still real.
- ZincHigh confidence
Strong evidence where there is deficiency or a specific indication. No benefit in replete people — including for testosterone — and excess causes copper deficiency.
- Vitamin DHigh confidence
Effective for deficiency and for bone health in at-risk groups. For broad disease prevention in adults who are already replete, the largest trials are null — and confidence in that null is high. Routine testing of healthy adults is not supported.
- Inhaled CorticosteroidsHigh confidence
The cornerstone of asthma treatment: fewer attacks, fewer admissions, fewer deaths. Reliever-only treatment is no longer recommended at any severity. Not the steroids used in sport. In COPD the indication is narrow — exacerbators with higher eosinophils — and pneumonia risk rises.
New to this? Read these first
How this usually unfolds
- Recognize risk factors
- Get diagnosed
- Track key biomarkers
- Lifestyle first
- Evidence-based treatment
- Long-term monitoring
Who is at risk
- Recent viral upper respiratory infection — the commonest precursor by far
- Allergic rhinitis and hay fever
- Nasal polyps
- Smoking
- Structural problems — a deviated septum
- Asthma — frequently coexists with chronic sinusitis
- Immunodeficiency
- Dental infection — an under-recognised cause of unilateral sinusitis
How it's diagnosed
Acute sinusitis is a clinical diagnosis and does not need imaging. The features that shift the balance toward a BACTERIAL cause — and therefore toward antibiotics — are specific: symptoms persisting beyond about ten days without improvement, severe symptoms with high fever and purulent discharge from the outset, or 'DOUBLE WORSENING', where you were getting better and then abruptly got worse again. Absent those, antibiotics are not indicated. Chronic sinusitis, lasting beyond twelve weeks, warrants nasal endoscopy and CT and referral, because it is a different condition.
Key biomarkers
Lifestyle
Explore this condition across BioSignal
Related Foundations
Related Signal Records
Related body systems
Frequently asked questions
My mucus is green. Doesn't that mean I need antibiotics?
No, and this is probably the single most useful thing on this page. Green or yellow mucus does NOT indicate bacterial infection. The colour comes from an enzyme (myeloperoxidase) released by your own neutrophils — your immune cells — as they fight the infection, and it appears in perfectly ordinary viral colds, usually a few days in. Green snot means your immune system is working. It does not mean you need an antibiotic, and this belief drives an enormous amount of unnecessary prescribing, side effects, and antibiotic resistance. Almost all acute sinusitis is viral and resolves on its own.
When DO I need antibiotics?
There are three specific patterns, and outside them you almost certainly do not. Symptoms that persist beyond about TEN DAYS without any improvement. Symptoms that are SEVERE FROM THE OUTSET — high fever with purulent discharge and facial pain. Or DOUBLE WORSENING: you were getting better, and then abruptly got worse again. That last one is the classic sign that a viral illness has been complicated by a bacterial one. If none of those describe you, the honest answer is that antibiotics will not speed your recovery and will give you the side effects for nothing.
What actually helps while I wait it out?
Saline nasal irrigation, which is cheap and effective and which almost nobody does because it does not feel like medicine. An intranasal corticosteroid spray, which is the best-evidenced treatment there is for sinusitis — used correctly, aimed away from the middle of the nose, and given several days to work, because people give up on day two. Painkillers. Decongestant sprays for a few days at most, because using them longer causes rebound congestion that is worse than the original. And time: most acute sinusitis settles within two to three weeks.
When is sinusitis an emergency?
When it spreads beyond the sinuses, which is rare and serious. Go to an emergency department if you develop swelling, redness or pain AROUND THE EYE; any change in vision or double vision; a severe or unusual headache; confusion; or a stiff neck. The sinuses sit directly against the orbit and the brain, and infection can spread into either. These complications are uncommon — but they threaten sight and life, and they are the reason 'just sinusitis' is not always just sinusitis.
Evidence summary
Acute sinusitis is predominantly viral and self-limiting; systematic reviews demonstrate that antibiotics confer little or no benefit for most patients, with a small absolute effect on symptom duration offset by adverse effects, and acute sinusitis remains a leading driver of inappropriate antibiotic prescribing. Purulent (green or yellow) nasal discharge reflects neutrophil myeloperoxidase and does not indicate bacterial infection. Features that raise the probability of bacterial infection are symptom persistence beyond about ten days without improvement, severe symptoms with fever and purulence at onset, and 'double worsening'. Intranasal corticosteroids have supporting randomized evidence in both acute and chronic rhinosinusitis; saline irrigation is beneficial and low-risk. Chronic rhinosinusitis (>12 weeks) is an inflammatory disorder frequently associated with allergy and nasal polyposis and is managed differently from acute infection. Orbital and intracranial complications, though uncommon, are sight- and life-threatening and constitute medical emergencies.
References & sources
- EPOS — European Position Paper on Rhinosinusitis and Nasal Polyps
- Cochrane reviews of antibiotics for acute maxillary sinusitis
- NICE NG79 — Sinusitis (acute): antimicrobial prescribing
- Cochrane reviews of intranasal corticosteroids and saline irrigation for rhinosinusitis
Educational information — not medical advice
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