What are the management options for environmental allergies?

Environmental Allergy Management

Environmental allergy management should begin with confirming specific allergen sensitization through skin testing or specific IgE testing, followed by tailored multicomponent allergen avoidance strategies targeting only the allergens to which the patient is sensitized, combined with second-generation oral antihistamines or intranasal corticosteroids for symptomatic control. 1

Initial Assessment and Testing

Confirm allergic sensitization before implementing avoidance measures. The diagnosis should be confirmed with skin testing or in vitro testing for specific IgE antibodies to indoor allergens, as these tests identify the specific allergens affecting each patient and allow for appropriate targeted advice. 1 However, testing requires confirming clinical history and should not be used alone to determine allergic status. 1

Key Clinical History Elements

• Symptoms during spring or fall pollen seasons 1
• Symptoms during exposure to animals, house cleaning, or damp musty environments 1
• Personal or family history of allergic rhinitis, asthma, or atopic dermatitis 1

Allergen-Specific Avoidance Strategies

When to Implement Avoidance Measures

Only implement allergen mitigation for patients with confirmed sensitization or symptoms related to specific allergen exposure. For individuals without sensitization to specific indoor allergens or without symptoms related to exposure, allergen mitigation interventions are not recommended as part of routine management. 1

For sensitized patients with symptoms, use multicomponent interventions—single interventions rarely work. 1

Dust Mite Control (for sensitized patients)

Dust mite allergen levels above 2 μg/g settled dust are a risk factor for sensitization. 1 Mites infest fabrics in homes, with heaviest exposure occurring from bedding during sleep. 1

Bedroom-focused multicomponent approach:

• Encase pillows and mattresses with impermeable covers (less than 10 μm pore size, fine weave, or vapor-permeable) 1, 2, 3
• Wash all bedding weekly in hot water (greater than 130°F) 2, 3
• Use HEPA filtration vacuum cleaners for weekly cleaning 1, 2
• Remove carpets and replace with hard surface flooring 1
• Replace upholstered furniture with leather, vinyl, or wood 3
• Replace draperies with washable shades or blinds 3

Critical pitfall: Impermeable pillow and mattress covers alone do not improve outcomes and should only be used as part of a multicomponent intervention. 1

Cat Allergen Control (for sensitized patients)

Cat allergen (Fel d 1) is found in all cat breeds and persists in air for extended periods due to small, low-density particles. 2, 3

Complete cat removal is the single most effective intervention. 1, 2, 3 However, allergen persists for an average of 20 weeks after removal, so short trial removals (days or weeks) are misleading. 1, 2, 3

If removal is not possible:

• Confine the cat to an uncarpeted room (not the bedroom) with HEPA filtration, which may reduce airborne allergen in the rest of the home by up to 90% 1, 2, 3
• Keep the cat out of the patient's bedroom at all times 2, 3
• Bathe the cat weekly to temporarily reduce airborne allergen 1, 2, 3
• Use bedroom environmental controls as described for dust mites 2, 3

Critical pitfall: Do not assume certain cat breeds are "hypoallergenic"—all breeds produce Fel d 1 allergen. 2, 3

Cockroach and Rodent Control (for sensitized patients)

Use integrated pest management alone or as part of multicomponent intervention. 1 Cockroach allergen is most abundant in kitchen areas. 1

Integrated pest management approach:

• Emphasize food debris removal and seal all food sources 1
• Use newer gel or bait pesticides (hydramethylnon, abamectin) 1
• Implement repetitive home cleaning 1
• Structurally eliminate harborages 1

Aggressive pest management may require more than 6 months to remove residual cockroach allergen. 1

Fungal Allergen Control (for sensitized patients)

Indoor fungal levels exceeding 1000 spores/m³ or 1000-10,000 colony-forming units/m³ suggest indoor contamination. 1

Two-step approach:

• First: Eliminate moisture sources (water leaks, cold surfaces, elevated humidity) through dehumidification, sealing leaks, and ventilating bathrooms/kitchens 1
• Second: Apply dilute bleach solution with detergent to nonporous surfaces; remove and replace porous surfaces 1

Additional measures:

• Close doors and windows; use air conditioning to prevent spore infiltration 1
• Use dehumidifiers to maintain low humidity 1
• Use high-efficiency air filters 1
• Wear particle masks when cleaning contaminated materials 1

Pollen Control (for sensitized patients)

Pollen types vary by locale and season—trees predominate in early-to-mid spring, grasses in late spring/early summer, and weeds from late summer to early fall in temperate North America. 1

Outdoor pollen avoidance:

• Keep windows and doors closed during pollen season 1
• Use air conditioning with outdoor vents closed 1
• Limit outdoor exposure when pollen counts are high 1
• Shower or bathe after outdoor activity 1
• Wash pets after outdoor exposure 1

Pharmacologic Management

Second-generation oral antihistamines are preferred over first-generation antihistamines due to less sedation, performance impairment, and anticholinergic adverse effects. 1, 2, 4 These provide 24-hour relief of sneezing, runny nose, itchy/watery eyes, and itchy throat or nose. 4

Intranasal corticosteroids are effective for reducing nasal airway resistance and symptoms. 1, 5

Implementation Principles

Tailor interventions to individual allergen sensitivities and exposures. 1 Most patients with allergic disease are sensitive to more than one allergen, so addressing multiple exposures simultaneously is often necessary. 1

Simplify the regimen to improve adherence. Patient adherence increases when recommendations are simplified and a cooperative partnership is established between physician and patient. 1

Judge success by clinical improvement (reduction in symptoms and medication use), not solely by allergen concentration reduction. 1

Consider allergen testing before committing patients to burdensome mitigation strategies. 1 The tailored, individualized approach matching specific sensitivities to exposures has proven highly effective, with studies showing 13.5-19.5% reductions in symptom days. 1