Non-allergic rhinitis

Introduction
Non-allergic rhinitis (NAR) is a chronic nasal condition characterized by symptoms such as nasal congestion, rhinorrhoea (runny nose), sneezing, and postnasal drip that are not triggered by allergens and do not involve IgE-mediated immune responses. Unlike allergic rhinitis, NAR is not associated with positive allergy testing (skin prick or serum-specific IgE). The condition can be idiopathic or triggered by a variety of non-allergic stimuli and is common in adults, with a significant impact on quality of life.

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Epidemiology

• Accounts for approximately 20–25% of all cases of chronic rhinitis.

• More common in adults than children.

• Typically presents after age 20.

• No clear seasonal variation unless triggered by environmental irritants.

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Etiology and Triggers

NAR has multiple potential causes and may involve a combination of factors that result in hyper-responsiveness of the nasal mucosa.

Common Triggers

• Environmental irritants: smoke, perfumes, cleaning chemicals, pollution.

• Weather changes: temperature fluctuations, humidity changes, barometric pressure.

• Strong odours: paints, solvents, scented products.

• Foods and beverages: particularly spicy or hot foods (gustatory rhinitis).

• Hormonal changes: pregnancy, menstruation, hypothyroidism.

• Medications:

  • β-blockers

  • ACE inhibitors

  • Aspirin and NSAIDs

  • Oral contraceptives

  • Overuse of topical nasal decongestants (rhinitis medicamentosa)

• Occupational exposures: dust, fumes, chemicals.

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Pathophysiology

• Not fully understood; thought to involve abnormal regulation of nasal vascular tone and heightened sensitivity of nasal sensory nerves.

• Neurogenic inflammation and increased cholinergic activity may play a role.

• Unlike allergic rhinitis, there is no IgE-mediated mast cell degranulation.

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Clinical Presentation

Symptoms (often chronic or recurrent)

• Nasal congestion.

• Clear rhinorrhoea (can be watery or mucoid).

• Postnasal drip.

• Sneezing (less pronounced than in allergic rhinitis).

• Possible hyposmia (reduced sense of smell).

Signs

• Nasal mucosa may appear pale or erythematous.

• Absence of nasal polyps in most cases (unless coexistent chronic rhinosinusitis).

• No allergic shiners or conjunctival injection typically seen in allergic rhinitis.

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Diagnosis

Clinical Diagnosis – Based on:

• Chronic rhinitis symptoms.

• Absence of identifiable allergic triggers.

• Negative allergy testing.

Investigations

• Allergy testing (skin prick or serum IgE) to rule out allergic rhinitis.

• Nasal endoscopy if structural abnormalities or chronic rhinosinusitis suspected.

• Consider sinus CT in refractory or complicated cases.

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Differential Diagnosis

• Allergic rhinitis.

• Infectious rhinitis (viral or bacterial).

• Chronic rhinosinusitis.

• Nasal polyps.

• Cerebrospinal fluid leak (rare, in unilateral watery rhinorrhoea).

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Management

Management focuses on symptom control, trigger avoidance, and treatment of underlying contributing factors.

1. Trigger Avoidance

• Identify and avoid known irritants (e.g., smoke, perfumes).

• Manage environmental humidity.

• Wear masks in occupational exposure settings.

2. Pharmacologic Therapy

Intranasal Corticosteroids – First-line for persistent symptoms

• Fluticasone propionate: 50 mcg per spray, 1–2 sprays per nostril once daily.

• Mometasone furoate: 50 mcg per spray, 2 sprays per nostril once daily.

• Budesonide: 64 mcg per spray, 1 spray per nostril twice daily.

Intranasal Antihistamines – Useful even without allergy

• Azelastine: 137 mcg per spray, 1–2 sprays per nostril twice daily.

• Olopatadine: 665 mcg per spray, 2 sprays per nostril twice daily.

Intranasal Anticholinergics – Particularly for watery rhinorrhoea

• Ipratropium bromide: 0.03% or 0.06% nasal spray, 2 sprays per nostril 2–3 times daily.

Oral Decongestants – For short-term relief

• Pseudoephedrine: 60 mg orally every 4–6 hours (max 240 mg/day).

• Use with caution in hypertension, cardiovascular disease, and avoid prolonged use.

Saline Irrigation – Reduces mucosal irritants and improves mucociliary clearance

• Isotonic or hypertonic saline, 50–250 mL per nostril once or twice daily.

3. Special Subtypes

• Gustatory rhinitis: Ipratropium bromide nasal spray before meals.

• Hormonal rhinitis: Usually self-limiting, symptomatic treatment during pregnancy.

• Drug-induced rhinitis: Discontinue offending agent if possible.

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Surgical Intervention

Considered in refractory cases with structural abnormalities or when symptoms persist despite optimal medical management.

• Septoplasty (for significant septal deviation).

• Inferior turbinate reduction (e.g., radiofrequency ablation).

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Prognosis

• Chronic but benign condition.

• Symptom control is usually achievable with consistent trigger avoidance and medical therapy.

• Relapses are common if exposure to irritants continues.