Chronic Rhinosinusitis with Nasal Polyps

CRSwNPNasal PolyposisEosinophilic CRS

Chronic rhinosinusitis with nasal polyps (CRSwNP) is a chronic inflammatory disease of the sinonasal mucosa characterised by bilateral polyp growth, persistent nasal obstruction, anosmia, and impaired quality of life. Driven predominantly by type 2 inflammation — with IL-4, IL-5, IL-13, and IgE as key mediators — CRSwNP affects 1–4% of the general population and 20–30% of all chronic rhinosinusitis patients.

reported casesDiscovered 1000Last updated Feb 24, 2026

Understanding status

Pathophysiology
Partially understood
55%
Treatment
Effective options available
80%
Genetic basis
Under investigation
35%

Epidemiology

Total cases
Unknown
Mean onset
42 years
Onset range
20–70 years
Sex ratio (M:F)
1.5:1
Diagnostic delay
~3 years
Discovered
1000 (Ancient Egyptian physicians (earliest surgical descriptions))
Prevalence
1–4%
Classification
Inflammatory, Otorhinolaryngologic

Cardinal features

8 key symptoms and signs

FeatureFrequencyCategorySources
Nasal obstruction/congestion
Bilateral nasal blockage, often progressive and unresponsive to decongestants. Worse on lying down. Most bothersome symptom reported by patients.
95%sinonasal
Anosmia/hyposmia
Loss or reduction of smell is a hallmark feature, often the earliest and most distressing symptom. Strongly correlates with eosinophilic inflammation and polyp burden. May persist after surgery without biologic therapy.
85%sinonasal
Anterior/posterior rhinorrhea
Thick, mucopurulent or clear nasal discharge. Posterior nasal drip causes throat clearing and cough.
80%sinonasal
Facial pain/pressure
Dull pressure over cheeks, forehead, or between eyes. Less prominent in CRSwNP than in CRS without polyps.
60%sinonasal
Impaired quality of life
SNOT-22 scores significantly elevated. Sleep disturbance, fatigue, and reduced productivity. Impact comparable to COPD and heart failure.
90%systemic
Taste dysfunction
Closely linked to anosmia. Reduced flavour perception significantly impacts nutrition and quality of life.
70%sinonasal
Sleep disturbance
Mouth breathing, snoring, and obstructive sleep apnoea secondary to nasal obstruction.
75%systemic
Blood eosinophilia
Peripheral blood eosinophils >300 cells/μL in majority of patients. Correlates with disease severity and recurrence risk.
70%laboratory

Hypothesis tracker

Competing explanations ranked by evidence weight

#1leading
Epithelial barrier dysfunction is the primary initiating event, with alarmin release driving type 2 polarisation
120 studies·pathogenesis
70
evidence
#2leading
CRSwNP is a unified airway disease — upper and lower airway inflammation share common type 2 mechanisms
150 studies·pathogenesis
65
evidence
#3competing
Eosinophil-mediated tissue damage creates a self-perpetuating inflammatory cycle
90 studies·pathogenesis
60
evidence
#4leading
Endotype classification (type 2 vs non-type 2) should guide treatment selection
100 studies·treatment
60
evidence
#5competing
Staphylococcus aureus superantigens drive local immune activation and disease persistence
80 studies·pathogenesis
55
evidence
#6emerging
Epigenetic reprogramming by environmental exposures shapes disease susceptibility
25 studies·genetics
30
evidence

Open questions

1
Why do only some CRS patients develop nasal polyps?
CRS without polyps (CRSsNP) and CRSwNP share the same sinuses but have fundamentally different inflammatory profiles. What tips the balance toward polyp formation?
2
How should biologics be selected and sequenced for individual patients?
Four approved biologics target different molecules. No head-to-head trials exist. Biomarker-driven selection is theoretically attractive but unvalidated prospectively.
3
Can biologics achieve disease remission or only suppression?
Most trials show polyp regrowth upon biologic discontinuation. Whether long-term treatment can fundamentally reset the immune environment is unknown.
4
What drives the geographic variation in CRSwNP endotypes?
Western CRSwNP is predominantly eosinophilic/type 2, while East Asian CRSwNP historically had more neutrophilic/non-type 2 disease — though this is shifting toward Western patterns with urbanisation.
5
What is the role of the sinonasal microbiome in disease initiation and persistence?
S. aureus colonisation is associated with severe disease, but whether dysbiosis is cause or consequence remains debated. Microbiome-targeted therapies are unexplored.
6
Can upstream alarmin blockade (anti-TSLP, anti-IL-33) prevent disease rather than just suppress it?
Current biologics target downstream effectors. Blocking epithelial alarmins might intervene earlier in the cascade and potentially modify disease course.

Recent updates

treatment update
Benralizumab (anti-IL-5Rα) FDA-approved for CRSwNP (2024)
OSTRO trial led to FDA approval of benralizumab for CRSwNP in 2024, making it the fourth approved biologic. Unique ADCC mechanism achieves near-complete eosinophil depletion.
new research
Head-to-head biologic comparison studies beginning
First trials comparing dupilumab, omalizumab, and mepolizumab head-to-head are enrolling, which may finally guide evidence-based biologic selection.
new research
Alarmin-targeting biologics in development for CRSwNP
Tezepelumab (anti-TSLP) and itepekimab (anti-IL-33) are in phase 2/3 trials for CRSwNP, targeting upstream epithelial alarmins as a novel therapeutic approach.
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