House dust mite avoidance measures for perennial allergic rhinitis: a systematic review of efficacy.

Perennial allergic rhinitis is a common chronic disorder that results most frequently from sensitivity to house dust mites. National and international guidelines for the management of allergic rhinitis recommend that house dust mite avoidance measures be considered in all patients with house dust mite-provoked rhinitis. To assess the benefit and harm of measures designed to reduce house dust mite exposure in the management of house dust mite-sensitive allergic rhinitis, published and unpublished randomised controlled trials were systematically searched. A methodological assessment of trial quality was conducted using the Cochrane approach. Four trials satisfied the inclusion criteria, all of which were small and judged to be of poor quality. The results indicate that, when compared with controls, significant reductions of allergen load can be achieved by physical and chemical means, but there is little evidence at present that these reductions translate into sustained improvements in clinical outcomes. No serious adverse effects were reported from the interventions.