Rhinitis - Allergic

Definition

Allergic rhinitis is an IgE-mediated inflammatory condition of the nasal mucosa triggered by allergens, characterized by nasal congestion, rhinorrhea, sneezing, and itching. It can be seasonal or perennial.

Epidemiology

• Affects 10–30% of adults and up to 40% of children worldwide
• Prevalence higher in urban areas and industrialized countries
• Often associated with atopic conditions such as asthma and eczema
• More common in individuals with family history of atopy
• Symptoms can significantly impair quality of life and productivity

Etiology

• Environmental allergens: pollen, dust mites, mold spores, animal dander
• Occupational allergens: chemicals, latex, dust
• Genetic predisposition (family history of atopy)
• Air pollution may exacerbate symptoms
• Comorbid conditions: asthma, eczema, sinusitis
• Seasonal exposure triggers in pollen-sensitive individuals

Pathophysiology

• Allergen exposure triggers IgE-mediated mast cell activation
• Release of histamine, leukotrienes, and other inflammatory mediators
• Nasal mucosal inflammation with increased vascular permeability
• Edema and nasal congestion due to vasodilation and fluid leakage
• Mucus hypersecretion causing rhinorrhea
• Sensory nerve stimulation resulting in sneezing and itching
• Chronic exposure can lead to persistent inflammation and mucosal remodeling