House dust control and asthma: a placebo-control trial of cleaning air filtration

Using a placebo-control single-blind crossover trial, we investigated the effects of dust control measures alone and combined with electrostatic and high efficiency particulate air filters in the bedrooms of patients with asthma. Of 12 young asthmatics allergic to house dust and dust mite who entered the trial, nine completed all four 2-week intervals. No statistically significant improvement in symptom scores or peak expiratory flow above that recorded during the placebo interval occurred during any treatment phase. We conclude that house dust suppression adds little to the management of otherwise well controlled young asthmatic patients.