EFFECT OF APPLICATION OF BENZYL BENZOATE ON HOUSE-DUST MITE ALLERGEN LEVELS

Background: Several acaricides have become available for reducing hous e dust mite allergen levels. Objective: The purpose of this study was to assess whether the use of benzyl benzoate (Acarosan) provides addit ional benefit to the usual mite control measures including encasement of mattress and pillows with vinyl covers. Methods: A randomized contr olled trial was carried out in 26 homes (14 control versus 12 treatmen t) of asthmatic patients in two cities (Vancouver and Winnipeg). The c ontrol group had the usual house dust mite control measures including the use of vinyl covers for mattresses and pillows while the treatment group had application of benzyl benzoate to mattresses and carpets in the bedroom and the most commonly used room, in addition to the above control measures. Mite allergen levels were measured 3 months and imm ediately before, 1 week, and 1 and 3 months after the application of h ouse dust mite control measures. Patients kept diary cards on asthma s ymptoms and peak expiratory flow rates morning and evening one month b efore and three months after the onset of mite allergen control measur es. Results: A reduction of mite allergen level was found in mattress samples in both groups, statistically significant at all times in the treatment group and at one and three months in the control group, Mite allergen levels on floor carpets also showed progressive reduction in both groups, but were significantly different in the treatment group (compared with controls) at 1 week, and were lower compared with basel ine in the treatment group up to 3 months. No significant changes in a sthma symptoms, peak expiratory flow rates, spirometric measurements, or bronchial hyperresponsiveness were observed among treatment or cont rol group subjects. Conclusion: The addition of benzyl benzoate to con ventional house dust mite control measures resulted in a significant r eduction in floor carpet dust mite levels that persisted for 3 months. The results of this study should be confirmed in a larger and longer study.