Domestic control of house dust mite allergen in children's beds

Background: House dust mite allergen levels in humid coastal regions of Aus tralia are high, particularly in beds. Because high allergen levels in beds are associated with more severe asthma, reduction of levels may be importa nt for asthma control. Objective: We tested the effectiveness of an acaricidal treatment of beddin g in combination with occlusive mattress and pillow encasings in reducing a llergen levels in children's beds in a community setting. Methods: A total of 14 beds of children were selected for the active interv ention. In each home the bed of a sibling of nearest age was selected as th e control. Dust was vacuumed from beds by using a standard protocol, and De r p 1 levels mere measured by using ELISA. Adjacent settling dust was colle cted by using opened Petri dishes. The intervention consisted of encasing m attresses and pillows in occlusive covers and washing all bedding with Acar il, an acaricidal additive. The acaricidal wash mas repeated twice in 7 hou seholds at 2-month inter vals. Control beds mere not treated. Results: The mean Der p 1 concentration at baseline was 27.9 mu g/g in the active beds and 18.1 mu g/g in the control beds. At 4 days after interventi on, Der p 1 decreased to 32 mu g/g and 15.7 mu g/g in active and control be ds, respectively. The average difference (active minus control) over the fi rst 1-week cycle was 78.5% (P < .0001), and the difference over 3 washing c ycles was 125.1% (P < .05). The mean rate of settling Der p 1 adjacent to t he actively treated beds decreased from 24.4 ng.m(-2).d(-1) at baseline to 10.0 ng.m(-2).d(-1) after intervention (P < .01). Conclusion: A substantial reduction in Der p 1 levels in beds and in airbor ne dust in a humid region with naturally high house dust mite allergen leve ls can be achieved and sustained in a community setting with use of occlusi ve covers and a rigorous washing routine.