Step 1 of 8
Diagnostic Criteria & Red-Flag Triage
≥12 weeks + ≥2 cardinal symptoms (one = obstruction/discharge); screen orbital, intracranial, malignancy & invasive-fungal red flags
Chronic rhinosinusitis is suspected when sinonasal symptoms persist for at least 12 weeks, and the diagnosis requires at least two of the four cardinal symptoms — nasal obstruction/congestion, nasal discharge (anterior or posterior), facial pressure/pain/fullness, and reduction or loss of smell — with at least one being obstruction or discharge. Supporting symptoms (headache, halitosis, fatigue, dental pain, ear fullness, chronic cough, sleep disturbance) add to the picture but do not substitute for the cardinal pair.
Before settling into the routine pathway, every patient is screened for red flags that demand urgent imaging, admission, and specialist management. Orbital complications — periorbital oedema, proptosis, diplopia, ophthalmoplegia, reduced visual acuity — threaten sight; intracranial complications — severe frontal headache, meningism, altered consciousness, focal deficits, seizures — threaten life; malignancy indicators — unilateral symptoms, recurrent epistaxis, facial numbness, cranial neuropathy, neck mass, weight loss — must not be missed; and invasive fungal sinusitis in the diabetic or immunosuppressed patient (black eschar, severe facial pain) is an emergency. Where any of these is present, the patient leaves the CRS algorithm for urgent imaging and management; where none is present, the comprehensive CRS work-up proceeds.
- Suspect CRS — symptoms ≥12 weeks; require ≥2 cardinal symptoms with one being obstruction or discharge
- Cardinal — obstruction/congestion, discharge (anterior/posterior), facial pressure/pain, hyposmia/anosmia
- Red flags — orbital (proptosis/diplopia/visual loss), intracranial (meningism/altered consciousness/deficit), malignancy (unilateral/epistaxis/numbness/neck mass), invasive fungal (diabetes/immunosuppression + eschar)
- Any red flag → urgent imaging + admission + specialist management
★ High-yield pearls (chapter-wide)
- Chronic rhinosinusitis is a clinical-plus-objective diagnosis — at least 12 weeks of two cardinal symptoms (one being nasal obstruction or discharge) PLUS endoscopic or CT evidence of inflammation; symptoms alone do not make the diagnosis.
- Nasal endoscopy is essential in every CRS work-up — it confirms the inflammation, stages the polyps, and is the investigation that catches the unilateral mass masquerading as sinusitis.
- The first and most important split is CRS without polyps (CRSsNP, often neutrophilic and localised) versus CRS with polyps (CRSwNP, usually eosinophilic, Type-2, smell-destroying, and recurrent).
- Saline irrigation and intranasal corticosteroids are first-line for every CRS phenotype and are continued long-term — most of the medical benefit comes from getting these two right.
- Unilateral sinonasal disease, recurrent epistaxis, facial numbness or a cranial neuropathy is malignancy until imaging and biopsy prove otherwise — never assume a one-sided sinus opacity is simple CRS.
- Acute invasive fungal sinusitis in a diabetic or immunocompromised patient — black eschar, severe pain, numbness — is a surgical emergency needing urgent debridement, systemic antifungals, and reversal of immunosuppression.
- Type-2 CRSwNP — eosinophilia, raised IgE, asthma, AERD, recurrent polyps after surgery — is the endotype that responds to biologics (dupilumab, omalizumab, mepolizumab, benralizumab).
- Aspirin-exacerbated respiratory disease (asthma + nasal polyps + NSAID sensitivity) recurs aggressively after surgery — recognise Samter's triad and consider aspirin desensitisation or a biologic.
- Nasal polyps in a child are not ordinary CRS — always investigate for cystic fibrosis (sweat chloride, CFTR) and primary ciliary dyskinesia (nasal nitric oxide, genetics).
- Endoscopic sinus surgery does not cure CRS — it restores ventilation, drainage and access for topical therapy, and the long-term result depends on continued saline, steroids, and control of allergy, asthma and Type-2 inflammation.
Evidence base
3 sources- HIGH
Fokkens WJ, Lund VJ, Hopkins C · Rhinology · 2020Position paper / guidelinePMID 32077450
EPOS 2020 — the European position paper defining the diagnostic criteria, phenotype/endotype classification, and integrated-care management of chronic rhinosinusitis with and without nasal polyps.
- HIGH
Orlandi RR, Kingdom TT, Smith TL · Int Forum Allergy Rhinol · 2021Consensus statementPMID 33236525
ICAR:RS 2021 — the international evidence-based consensus on the diagnosis, work-up (endoscopy, CT, comorbidity testing), medical therapy, and surgery of rhinosinusitis.
- HIGH
Beule A · Dtsch Arztebl Int · 2024ReviewPMID 39173076
Contemporary review of the diagnosis and treatment of chronic rhinosinusitis — the diagnostic criteria, phenotyping, the saline-and-steroid backbone, surgery, and biologics.
Decision tree
The triage screen is the first gate. Classification routes the stable patient to one of the aetiology-keyed pathways below. Cross-cut cards capture the chapter's must-not-miss rules.