Table 1.

Overview of the three main inflammatory sinonasal phenotypes with their characteristics (CRS, chronic rhinosinusitis).

Phenotype	Allergic rhinitis	Eosinophilic CRS	Non-eosinophilic CRS
Type of secretions	Watery secretions	Thick tenacious mucin	Discolored secretions
Appearance of eosinophilic cells	Intact eosinophilic cells	Necrotic eosinophilic cells (ETosis)	Mainly neutrophilic cells (NTosis)
Charcot-Leyden crystals (CLC)	No CLC	CLC present	No CLC
Appearance of granules	No granules, no proteins	Granule proteins	Free eosinophilic granules
Type of cytokines	T2 cytokines	T2 cytokines	T1 cytokines
Typical age of patients	Likely young population	Likely older population	Diverse
IgE involvement	Evidence of IgE-mediated	IgE not necessarily present	IgE not likely
Presence of nasal polyps	Nasal polyposis not likely	Nasal polyposis likely	(Small) nasal polyps possible
State of mucosal lining	No damage of mucosal lining	Possible mucosal damage	Possible mucosal damage
Presence of hyphae	No hyphae	Hyphae possible	Hyphae not likely
Presence of major basic protein (MBP)	No MBP	MBP present	MBP not likely
CT appearance	Typical black halo on CT	Possible CT hyperattenuation	Atypical sinusitis on CT
Presence of asthma	Asthma with early onset	Late-onset asthma, eosinophilic	Atypical asthma
Possibility of oral steroids	Oral steroids rarely	Oral steroids more frequently	Oral steroids rarely
Possibility of vaccination	Possible vaccination	Vaccination rarely	No vaccination considered
Standard oral therapy	Anti-allergic therapy	Steroids, monoclonal antibodies	Antibiotics
Typical evolution	Tendency to disappear with age	Tendency to aggravate with age	Aggravation with age (multifactorial)
Persistence of disease	Restricted lifetime pathology	Lifetime pathology	Multifactorial dependent lifetime