Nasal Polyps — Causes, Symptoms, Diagnosis & Treatment Guide — Symptoms, Causes & Treatment | MyMedicPlus

Nasal polyps (rhinopolyposis) are benign, teardrop-shaped outgrowths of the nasal and paranasal sinus mucosa, arising from chronic inflammation of the sinonasal epithelium. They are soft, oedematous, and pale or grey in colour, and hang within the nasal cavity, most commonly arising from the ethmoid sinuses around the middle meatus. Nasal polyps are strongly associated with type 2 eosinophilic inflammation — elevated IL-4, IL-5, and IL-13 cytokines drive tissue eosinophilia and mast cell proliferation. They affect approximately 2-4% of the general adult population. Chronic rhinosinusitis with nasal polyps (CRSwNP) is associated with asthma (40-70% of polyp patients), aspirin sensitivity (Samter's triad: polyps + asthma + aspirin hypersensitivity), cystic fibrosis, Churg-Strauss syndrome, and non-steroidal anti-inflammatory drug hypersensitivity. Nasal polyposis represents the severe end of the chronic rhinosinusitis spectrum and is driven by persistent type 2 eosinophilic inflammation; the recent recognition that biologics targeting the IL-4/IL-13 and IL-5 pathways can dramatically improve outcomes has transformed the management of severe and refractory cases.

The exact aetiology of nasal polyps is multifactorial. Type 2 inflammation (eosinophilic, IgE-mediated) is the dominant mechanism in most Western patients. Disruption of the sinonasal epithelial barrier allows exposure to environmental allergens, bacterial biofilms (Staphylococcus aureus — produces superantigens and IL-31 that drive eosinophilic inflammation), and fungi (Alternaria, Aspergillus). Risk factors include: chronic rhinosinusitis (the most important predisposing condition — polyps occur in 20-40% of CRS patients), asthma (particularly aspirin-sensitive asthma), aspirin-exacerbated respiratory disease (AERD — Samter's triad), allergic rhinitis, cystic fibrosis (bilateral polyps in children — always investigate), Churg-Strauss eosinophilic granulomatosis with polyangiitis (EGPA), male sex (2:1 male predominance), adult age (rare in children outside CF), and genetic predisposition. Unilateral polyps in adults should raise suspicion for neoplasm and warrant urgent ENT assessment.

The dominant symptom of nasal polyps is nasal obstruction (bilateral, often progressive and persistent — distinguishes from rhinitis, where blockage alternates sides). Hyposmia or anosmia (reduced or absent sense of smell — the most bothersome symptom for many patients; results from polyp obstruction of the olfactory cleft) is a hallmark symptom. Other symptoms: nasal discharge (anterior rhinorrhoea or postnasal drip), facial pressure or pain (from sinus obstruction), snoring, mouth breathing, and sleep disturbance. In aspirin-sensitive patients, inhaling aspirin or NSAIDs triggers acute severe asthma and rhinitis. Large polyps may rarely protrude visibly from the nostril. Nasal polyps do not typically cause pain unless complicated by secondary infection (acute sinusitis). Bilateral nasal obstruction with anosmia in an adult is a classic presentation warranting ENT referral.

Anterior rhinoscopy with a nasal speculum or otoscope can visualise large polyps in the anterior nasal cavity. Flexible nasal endoscopy (in clinic by an ENT specialist) provides definitive visualisation of polyps and their extent — glistening, pale, smooth, mobile masses arising from the middle meatus. CT sinuses (coronal views, non-contrast) is the imaging modality of choice: defines polyp extent, opacification of sinuses, anatomical variants, and guides surgical planning. MRI is used when neoplasm is suspected (polyps should not enhance on MRI; enhancing lesions suggest tumour). Allergy testing (skin prick testing, specific IgE — RAST) identifies sensitisation to aeroallergens. Aspirin challenge confirms aspirin-exacerbated respiratory disease. Cystic fibrosis sweat chloride test and CFTR mutation testing in children with bilateral polyps. Eosinophil count, total IgE, and FeNO (fractional exhaled nitric oxide) may guide treatment decisions.

Intranasal corticosteroid sprays (INS) — mometasone, fluticasone, budesonide — are the cornerstone of treatment: reduce polyp size, improve nasal obstruction and olfaction, and prevent polyp recurrence post-surgery. Directed at polyps (applied with head-down, tip-forward technique to reach the middle meatus). Oral corticosteroids (prednisolone 30-40 mg daily for 10-14 days — 'medical polypectomy') produce rapid and dramatic shrinkage of polyps, restoring smell within days; used for severe disease or pre-operatively; cannot be used long-term due to systemic side effects. Saline nasal irrigation (high-volume, low-pressure) reduces mucosal inflammation and improves medication delivery. Endoscopic sinus surgery (FESS — functional endoscopic sinus surgery): removes polyps and opens sinus drainage pathways; recurrence is common (50% within 5 years) without post-operative topical steroids; provides significant symptomatic improvement. Biologic therapy — dupilumab (anti-IL-4Rα — blocks both IL-4 and IL-13 signalling) is approved for severe CRSwNP inadequately controlled with corticosteroids and surgery; reduces polyp burden, restores olfaction, and reduces need for surgery significantly. Mepolizumab (anti-IL-5) and benralizumab are alternatives. Aspirin desensitisation for Samter's triad patients improves polyp control and asthma.

Untreated or inadequately managed nasal polyps cause progressive symptoms and lead to significant complications. Total nasal obstruction from large polyps filling the nasal cavity forces permanent mouth breathing — causing dry mouth, dental caries, halitosis, and disturbed sleep. Anosmia (complete loss of smell) and ageusia (loss of taste) profoundly affect quality of life, food enjoyment, and safety — inability to detect gas leaks or smoke. Chronic rhinosinusitis with nasal polyps (CRSwNP) causes recurrent sinusitis, facial pain, and chronic mucopurulent discharge from obstructed sinus drainage pathways. In aspirin-exacerbated respiratory disease (Samter's triad), coexisting asthma is frequently severe, requiring high-dose inhaled corticosteroids and biologic therapy. Obstructive sleep apnoea is worsened by nasal polyposis causing significant upper airway obstruction. Extension beyond the nasal cavity (rare but serious): extensive CRSwNP in immunocompromised patients — particularly those with primary immunodeficiency or cystic fibrosis — can result in orbital involvement (proptosis, diplopia) or intracranial extension. Recurrence after surgery is very common (50-80% within 5 years without maintenance intranasal corticosteroids), often requiring multiple procedures over a lifetime. Quality of life impairment from nasal polyposis is comparable to moderate COPD on standardised health metrics.

Consistent daily use of intranasal corticosteroid spray is the most important measure to prevent polyp regrowth after medical or surgical treatment. Nasal saline irrigation twice daily reduces inflammatory load and keeps the nasal mucosa clear of crusts and discharge. In aspirin-sensitive patients, avoid NSAIDs (use paracetamol instead) — NSAIDs trigger potentially severe bronchospasm and worsen nasal polyps. Control underlying asthma effectively (poorly controlled asthma drives sinonasal eosinophilic inflammation). Treat allergic rhinitis with antihistamines and specific immunotherapy (desensitisation). Reduce exposure to environmental triggers — mould, dust mites, cigarette smoke. Attend regular ENT follow-up with endoscopic review for early detection of polyp recurrence before complete symptomatic relapse. Post-FESS nasal irrigation is essential for mucosal healing.

See your GP for assessment and ENT referral for persistent bilateral nasal obstruction, loss of smell, or symptoms of chronic sinusitis lasting more than 12 weeks. Seek urgent ENT assessment for: a unilateral nasal polyp in an adult (must exclude malignancy — inverting papilloma or sinonasal carcinoma), a polyp in a child (requires investigation for cystic fibrosis), a rapidly enlarging nasal mass, nasal polyp associated with facial swelling, proptosis, or visual changes (orbital or intracranial extension), or bleeding from the nasal mass (polyps rarely bleed — bleeding suggests vascular or malignant lesion). Any patient with nasal polyps who has not responded adequately to intranasal corticosteroid sprays after 12 weeks of correctly applied treatment should be referred to an ENT specialist for endoscopic evaluation and consideration of surgical or biologic treatment options.