What are the diagnostic criteria for chronic rhinosinusitis?

Diagnostic Criteria for Chronic Rhinosinusitis

Chronic rhinosinusitis requires both symptom duration ≥12 weeks AND objective documentation of inflammation—symptoms alone are insufficient for diagnosis. 1

Core Symptom Requirements

The diagnosis mandates at least 2 of the following 4 cardinal symptoms persisting for ≥12 weeks: 1

• Nasal blockage/obstruction/congestion (one of the two mandatory symptoms per EPOS criteria) 1
• Nasal discharge (anterior/posterior mucopurulent drainage—the other mandatory symptom) 1
• Facial pain/pressure/fullness (more common in CRS without nasal polyps) 1
• Decreased sense of smell/hyposmia/anosmia (more common in CRS with nasal polyps) 1, 2

Critical distinction: EPOS criteria specifically require that one of the two symptoms must be either nasal discharge OR nasal blockage—facial pain or smell loss alone are insufficient. 1

Mandatory Objective Documentation

Symptoms alone have only 37-73% sensitivity for CRS diagnosis—objective confirmation is essential to distinguish CRS from other causes of chronic nasal symptoms. 3 You must document inflammation through at least one of the following: 1

Nasal Endoscopy (Preferred Method)

• Purulent mucus or edema in the middle meatus or ethmoid region 1
• Presence or absence of nasal polyps in nasal cavity or middle meatus 1
• Mucosal inflammation visualized in sinus drainage pathways 1

Nasal endoscopy is superior to anterior rhinoscopy because it provides better visualization of posterior nasal cavity, nasopharynx, and sinus drainage pathways. 1 However, up to 35% of CRS patients have normal endoscopic findings, making CT imaging critical when endoscopy is unrevealing. 3

CT Imaging (Gold Standard for Radiologic Confirmation)

• Radiographic evidence of paranasal sinus inflammation (mucosal thickening, sinus ostial obstruction, anatomical variants) 1, 3
• CT is strongly recommended but not absolutely required for initial diagnosis per RI guidelines 1
• CT becomes mandatory when symptoms persist despite optimal medical treatment or when endoscopy is normal but clinical suspicion remains high 1, 3
• Plain radiography has no role in CRS diagnosis—CT is the preferred imaging modality 1

Duration Threshold

Symptoms must persist for ≥12 weeks according to most guidelines (EPOS, RI, CPG:AS). 1 Some guidelines accept ≥8 weeks, but 12 weeks is the consensus standard. 1 This distinguishes CRS from recurrent acute rhinosinusitis (2-4 isolated episodes per year with complete resolution between episodes). 1

Important Clinical Pitfalls

Do not diagnose CRS based on symptoms alone—this is the most common error, as many conditions mimic CRS symptoms (neoplasm, headache disorders, dental pain). 1

Anterior rhinoscopy is insufficient—it has low sensitivity and specificity, particularly in children <6 years old (only 20-40% concordance with radiographic findings). 1

Transillumination should never be used as a sole diagnostic criterion (74% sensitivity, 47% specificity). 1

Subclassification for Treatment Planning

Once diagnosed, classify CRS as: 1

• CRS with nasal polyps (more likely to have anosmia, eosinophilic inflammation) 1
• CRS without nasal polyps (more likely to have facial pain/pressure) 1
• Allergic fungal rhinosinusitis (requires fungal-specific IgE, allergic mucin with fungal hyphae, no invasive disease) 1

Additional Workup Considerations

Allergy testing is recommended in patients with recurrent or difficult-to-treat CRS, as up to 60% have significant allergic sensitivities to perennial allergens. 1 Skin testing is the preferred method. 1

Consider evaluation for underlying conditions when CRS is refractory: immunodeficiency, ciliary dyskinesia, cystic fibrosis, anatomic abnormalities, aspirin-exacerbated respiratory disease. 1, 2