A COMBINED APPROACH TO REDUCE MITE ALLERGEN IN THE BEDROOM

Background Asthma is a common chronic disease of childhood. House dust mite (HDM) are known to be a major source of allergen affecting atopi c asthmatics. No single control method has been demonstrated to consis tently reduce asthma. Objective We investigated the effect of a combin ation of two methods of HDM allergen control on HDM allergen content i n the bedding and carpets of asthmatic children. Methods This was a do uble-blind placebo-controlled trial treating the bedrooms of 56 mite-s ensitive asthmatic children. The carpet and the mattress, duvet and pi llows (bedding) in the bedroom of children of the active group were tr eated with the acaricide Acarosan (benzyl benzoate). The bedding was t hen encased in vapour permeable waterproof fabric (Intervent - cotton coated with polyurethane) for 24 weeks. The carpet and bedding of the control group were treated with placebo and the bedding encased in cot ton covers for 24 weeks. Dust samples were collected from all these it ems in a standard manner at regular intervals and Der p I content anal ysed. Results The group with active treatment had a median reduction o f 480 ng (100%) in mite allergen from the mattress vs 215 ng (53%) red uction in placebo-treated group by 6 weeks. The Der p I content of the active group's bedding was always less than the placebo group after t reatment (P < 0.01). The acaricide applied to the carpets or inside th e mattress covers was ineffective in reducing allergen content. Conclu sion This study confirms the effectiveness of encasing covers in reduc ing the mite allergen exposure but indicates there is no further advan tage in applying acaricide simultaneously.