Methods and effectiveness of indoor environmental control

Learning Objectives: The purpose of this review is to describe recommended methods of decreasing exposure to indoor allergens. Data Sources: Data were obtained from published studies and reviews. Study Selection: The reviewed studies met these criteria: 1) measurement of environmental allergens; 2) selection of participants with clearly defined allergic airway disease confirmed by detection of allergen-specific immunoglobulin E; and 3) clearly defined clinical and environmental outcomes. The studies were conducted as controlled clinical trials and the results between treated and control groups were compared with appropriate statistics. Results: The results of these studies show that installing allergen proof encasings and washing bedding frequently reduces house-dust mite exposure by 10-fold or more and significantly improves clinical measures of asthma. Washing pets reduces allergen levels temporarily. Excluding the pet from the bedroom while installing allergen-proof encasings and operating air cleaner reduces airborne allergens although having no significant effect on allergic symptoms. Cockroach populations can be controlled for over 6 months and allergens can be reduced with controlled pesticide application and cleaning, but clinical correlates have not been reported. Methods to improve adherence to environmental control measures have not been tested but effective methods can be recommended from literature on medication adherence. Conclusions: For patients allergic to indoor allergens, reasonable recommendations include installation of allergen-impermeable encasings, frequent laundering of bedding, removing furred pets from the home, and controlling of cockroach populations with effective pesticides using the principles of integrated pest management.