#1leading
Epithelial barrier dysfunction is the primary initiating event, with alarmin release driving type 2 polarisation
120 studies·pathogenesis
70
evidence
Chronic Rhinosinusitis with Nasal Polyps
Also known asCRSwNPNasal 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.
⊕1–4% prevalenceUpdated Apr 15, 2026
Data sourced from 30 published studies with evidence grading (A–D). Last reviewed . Not medical advice.
Pathophysiology◐Partially understood
Treatment✓Effective options available
Genetic basis○Under investigation
Publications per year
1977: 1 study
772003: 1 study
2005: 1 study
2012: 1 study
2013: 1 study
2015: 2 studies
2016: 2 studies
2019: 5 studies
2020: 7 studies
2021: 1 study
2024: 3 studies
2025: 1 study
2026: 4 studies
26Epidemiology
- 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
| Feature | Frequency | Category | Sources |
|---|---|---|---|
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
#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
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?
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.
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.
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.
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.
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
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.
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.
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.