TABLE 1. Classification of Allergic Rhinitis

^a Daily activities include work, school, sports, and leisure.

Overview

Allergic rhinitis is a systemic disease with prominent nasal symptoms. It represents an immunoglobulin E (IgE)–mediated response to indoor and outdoor environmental allergens, particularly airborne allergens (aeroallergens).

The familiar terms “seasonal allergic rhinitis” and “perennial allergic rhinitis” have largely been replaced by a classification system that takes into account both the duration and severity of symptoms. Patients are classified as having mild intermittent, moderate-to-severe intermittent, mild persistent, or moderate-to-severe persistent allergic rhinitis (see Table 1).

Allergic rhinitis cannot be cured. The goals of therapy are to reduce symptoms and improve the patient’s functional status and sense of well-being.

Epidemiology

• An estimated 20% of adults and 40% of children in the United States have allergic rhinitis.
  
• Symptoms generally begin after 2 years of age; the number of cases decreases after age 65.

Etiology

• The pathogenesis of allergic rhinitis involves numerous cells and mediators. Patients become sensitized during initial allergen exposure. The response to subsequent allergen exposure consists of an early phase (beginning within minutes), cellular recruitment, and a late phase (beginning 2–4 hours after allergen exposure). Continued persistent inflammation “primes” the tissue, resulting in a lower threshold for both allergic and nonallergic triggers.
  
• Common outdoor environmental allergens include pollen, mold spores, and pollutants (e.g., ozone and diesel exhaust particles).
  
• Common indoor allergens include house-dust mites, cockroaches, mold spores, cigarette smoke, and pet dander.
  
• Occupational allergens include wool dust, latex, resins, biologic enzymes, organic dusts (e.g., flour), and various chemicals (e.g., isocyanate and glutaraldehyde).

Signs and Symptoms

• The main symptoms of allergic rhinitis are frequent, paroxysmal sneezing; watery anterior rhinorrhea; itching of the eyes, nose, and/or palate; and conjunctivitis (red, irritated eyes with prominent conjunctival blood vessels).
  
• Nasal congestion is a variable finding.
  
• In general, symptoms are worse upon awakening, improve during the day, and then may worsen again at night.

Complications

• Acute complications include sinusitis and otitis media with effusion.
  
• Chronic complications include nasal polyps, sleep apnea, and hyposmia (diminished sense of smell).

Treatment

General/Nonpharmacologic Treatment Measures

• Allergen avoidance is the primary nonpharmacologic treatment measure. Avoidance strategies depend on the specific allergen (see Table 2).
  
• Nasal wetting agents (e.g., saline, propylene, or polyethylene glycol sprays or gels) or nasal irrigation with warm saline (isotonic or hypertonic) delivered via a syringe or neti pot may relieve nasal mucosal irritation and dryness, thus decreasing nasal stuffiness, rhinorrhea, and sneezing.

TABLE 2. Allergen Avoidance Strategies

General

Consider weekly vacuuming of carpets, drapes, and upholstery with a HEPA filter-equipped vacuum cleaner

Cat-Derived Allergens

Although unproven, weekly cat baths may reduce the allergen load

Cockroaches

Keep areas clean

Store food tightly sealed

Treat infested areas with baits or pesticides

House-Dust Mites (Dermatophagoides spp.)

Reduce household humidity to <40%

Apply acaricides

Reduce mite-harboring dust by removing carpets, upholstered furniture, stuffed animals, and bookshelves from the patient’s bedroom and other areas of the house if possible

Reduce mite populations in bedding by encasing the mattress, box springs, and pillows with mite-impermeable materials. Bedding that cannot be encased should be washed at least weekly in hot (130°F [54.4°C]) water. Bedding that cannot be encased or laundered should be discarded.

Mold Spores

Avoid outdoor activities that disturb decaying plant material (e.g., raking leaves)

Reduce household humidity

Remove houseplants

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