House dust mite allergen avoidance: a randomized controlled trial of surface chemical treatment and encasement of bedding
Article first published online: 27 APR 2006
Clinical & Experimental Allergy
Volume 24, Issue 11, pages 1078–1083, November 1994
How to Cite
MARKS, G. B., TOVEY, E. R., GREEN, W., SHEARER, M., SALOME, C. M. and WOOLCOCK, A. J. (1994), House dust mite allergen avoidance: a randomized controlled trial of surface chemical treatment and encasement of bedding. Clinical & Experimental Allergy, 24: 1078–1083. doi: 10.1111/j.1365-2222.1994.tb02746.x
- Issue published online: 27 APR 2006
- Article first published online: 27 APR 2006
- Submitted 11 January 1994, revised 16 March 1994; accepted 5 July 1994.
To test the effectiveness of a house dust mite (HDM) allergen avoidance strategy we conducted a randomized controlled trial in 35 atopic subjects with asthma, aged 13 to 60 living in Sydney — a high HDM allergen environment. After a 3 month run-in period, subjects were randomized to active allergen avoidance treatment (n= 17) or placebo (n= 18) groups and followed for 6 months. The active treatment involved placing impermeable covers over the mattress, pillows and duvet and spraying the remaining bedding, as well as the carpets and furniture, with a tannic acid/acaricidal spray. Subjects kept a daily record of symptoms and peak expiratory flow rates and had 3 monthly assessments of lung function and airway hyperresponsiveness (AHR). Dust samples were collected from the bed, the bedroom floor and the living room floor at 3 monthly intervals and 2 weeks after the treatment. Mean HDM allergen levels at baseline at these sites were, in the active group, 15.5, 9.6 and 10.2μ/g Der p I/g of fine dust, and, in the placebo group 25.7, 11.8 and 6.3μg/g. Two weeks after the allergen avoidance treatment the HDM allergen level in the beds was reduced to 29% of baseline (95% CI 16.50%, P= 0.038 compared with placebo), but was not significantly different at 3 or 6 months. There was also no significant effect of the allergen avoidance treatment on symptom scores, peak flow variability, lung function or AHR (P > 0.1). We conclude that, in a high HDM allergen environment, simple chemical treatment and encasement of bedding is not sufficient to cause a sustained, beneficial reduction in allergen levels. Effective allergen avoidance requires an active strategy to remove allergen reservoirs and control accumulating allergen within the house.