Table 1.

A: Diagnostic criteria B: CRS classification as per EPOS 2020 for CRS4

A	B
PRIMARY SYMPTOMS Nasal blockage/ Obstruction/congestion	Primary CRS	Localized	Type 2	AFRS
			Non type 2	Anatomical variation- Isolated sinusitis.
ADDITIONAL SYMPTOMS Facial pain/pressure Olfactory dysfunction Hyposmia/Anosmia		Diffuse	Type 2	eCRS AFRS CCAD
			Non type 2	Non eCRS
DURATION Acute: >10 days to < 3 months. Chronic: > 3 months.	Secondary CRS	Localized	local pathology	Odontogenic Fungal ball Tumor
ENDOSCOPY Nasal polyps Mucopurulent discharge in the middle meatus. Oedema/ obstruction in the middle meatus.		Diffuse	Mechanical	PCD, CF
			Inflammatory	GPA, EGPA
			Immunity	HIV Selective IgA, IgG immunodeficiency
CT PNS Mucosal changes within the osteomeatal complex and / or sinuses

Table 1A: one primary + one additional symptom or two primary symptoms, along with signs either on endoscopy or CT PNS should be present for the diagnosis of CRS

Table 1B: CRS -chronic rhinosinusitis; eCRS - eosinophilic CRS; AFRS - allergic fungal rhinosinusitis; CCAD -central compartment allergic disease; PCD, primary ciliary dyskinesia.; CF - cystic fibrosis; GPA - granulomatosis with polyangiitis (Wegener’s disease); EGPA, eosinophilic granulomatosis with polyangiitis (Churg-Strauss disease), IgA, IgG – Immunoglobulin A and G