Rhinitis - Nonallergic

Definition

Nonallergic rhinitis is chronic nasal inflammation characterized by nasal congestion, rhinorrhea, sneezing, and postnasal drip not caused by IgE-mediated allergic mechanisms. It includes vasomotor, irritant-induced, hormonal, drug-induced, or idiopathic forms.

Epidemiology

• Affects 17–30% of adults worldwide
• More common in adults than children
• Slight female predominance, particularly in vasomotor or hormonal types
• Often underdiagnosed due to overlap with allergic rhinitis
• Prevalence may increase with exposure to irritants, pollution, or hormonal changes

Etiology

• Vasomotor rhinitis: autonomic imbalance causing nasal hyperreactivity
• Irritant-induced rhinitis: tobacco smoke, perfumes, chemical fumes, pollution
• Drug-induced rhinitis: intranasal decongestants (rebound), antihypertensives, aspirin, NSAIDs
• Hormonal rhinitis: pregnancy, hypothyroidism, menopause
• Infectious triggers: post-viral rhinitis
• Idiopathic: cause unknown in some cases

Pathophysiology

• Non-IgE mediated inflammation of nasal mucosa
• Autonomic dysregulation leading to vasodilation and edema
• Mucus hypersecretion due to glandular hyperactivity
• Sensory nerve hyperresponsiveness causing sneezing and rhinorrhea
• Chronic exposure to irritants leading to persistent mucosal inflammation
• Rebound congestion from overuse of topical decongestants
• Altered neuropeptide signaling contributing to nasal hyperreactivity