Does benzyl benzoate prevent colonization of new mattresses by mites? A prospective study.

In 12 house-dust-mite-infested double beds, one of the mattresses was replaced by a new one, the other being regarded as a mite source. All new mattresses were treated in a double-blind fashion, with either benzyl benzoate or placebo before being placed on the bed as well as 1 year later. They were examined for mites and allergen concentrations over a period of 18 months. This period of time covered two mite seasons. Dust samples were taken bimonthly and analyzed by guanine test strip, microscopic mite counting, and determination of the mite allergens Der p 1 (Dermatophagoides pteronyssinus) and Der f 1 (D. farinae) by ELISA. Although, at the end of the observation period, the new mattresses still had significantly lower mite and allergen levels than the old mattresses, there were no significant differences between the placebo and the benzyl benzoate groups. In our setting, benzyl benzoate plus frequent cleansing was not significantly more effective in controlling mites than frequent cleansing alone.