Rhinitis - Allergic (Pediatric)

Definition

Allergic rhinitis in children is an IgE-mediated inflammatory condition of the nasal mucosa triggered by exposure to allergens, resulting in sneezing, nasal congestion, rhinorrhea, and itching.

Epidemiology

• Affects 10–30% of children globally
• Commonly starts in early childhood and may persist into adolescence
• Higher prevalence in children with a family history of atopy
• Urban children and those exposed to environmental pollutants have increased risk
• Often coexists with asthma or atopic dermatitis (atopic march)

Etiology

• Allergens: pollen, dust mites, mold spores, pet dander, cockroach antigens
• Genetic predisposition to atopy
• Environmental factors: indoor pollutants, tobacco smoke, climate
• Early-life viral infections may predispose to allergic sensitization
• Coexisting conditions like asthma or eczema increase susceptibility

Pathophysiology

• Allergen exposure triggers IgE-mediated activation of mast cells
• Release of histamine and other inflammatory mediators causes nasal mucosal swelling
• Chronic exposure leads to recruitment of eosinophils, T-helper 2 cells, and cytokines
• Inflammation causes nasal congestion, rhinorrhea, sneezing, and itching
• Persistent inflammation may lead to mucosal hypertrophy and chronic sinusitis
• Associated ocular inflammation may cause allergic conjunctivitis