Purpose of review
This review examines the efficacy of environmental controls as part of the management for inhalant allergic disease (allergic rhinitis and allergic asthma).
Evidence of efficacy of environmental controls for allergic disease can be categorized into two types of studies: environmental controls reducing measured allergen levels and environmental controls affecting clinical outcomes (e.g., symptom scores, medication use, or measured lung function). Multiple environmental control strategies have demonstrated efficacy in reducing allergen levels; however, clinical benefit secondary to allergen reduction has been variable. Clinical benefit is seen more consistently in studies that remove the allergic patient from a high allergen environment, than in studies that attempt to reduce the allergen level within the home. Prevention of sensitization using environmental controls in the prenatal and infant periods has been studied, but it has been difficult to demonstrate a consistent reduction in the development of allergic disease or decrease symptom severity. Allergen exposure early in life may paradoxically promote tolerance in some populations and sensitizations in others.
Although many studies evaluating a single environmental control strategy fail to show an improvement in clinical outcomes, comprehensive environmental controls may provide some benefit. Additionally, studies that relocate patients to low allergen environments tend to demonstrate clinical improvement.