Effect of Allergen-Impermeable Bed Covers for Patients with House Dust Mite Sensitive Asthma in Korea

초록

Backgroud: Allergen avoidance is the most important treatment strategy in allergic diseases. Because many allergen avoidance trials use multiple interventions and strict management plans, application of such avoidance measure is often impractical. Although encasing bedding in allergen-impermeable covers is the most effective house dust mite (HDM) control measure, its efficacy and clinical effectiveness is uncertain in usual domestic environment in Korea. Objective: A double-blind, placebo-controlled trial was conducted to assess the effect of impermeable covers, without any other form of mite-reduction measures. Methods: Thirty-five patients with mild-to-moderate asthma and allergy to HDM were randomly assigned to receive impermeable (Allergy-X-Cover, Allergy C&C Co., Seoul, Korea) or non-impermeable (placebo) covers for their beddings, and used for 1 year without any strict management method for the covers. The concentration of HDM major allergen in dust from patients’ bedding was measured at baseline and every 2-month interval. Symptom score for previous week, visual-analogue scale for asthma symptom, asthma-specific quality of life (QOL) and PEF were assessed at baseline and every 2-month interval. Spirometry was performed at baseline and after 6 and 12 months. Results: Compared with placebo group, the amount of dust collected from bedding was decreased in active group. Active group showed decreased concentration of HDM Group 1 allergen in bedding dust during the first 6 months. Symptom score and visual-analogue scale was improved in active group more than in placebo group. In active group, PEF was significantly improved during the study period, and FEV1 was improved at 6 months. Asthma-specific QOL was improved in both group during 1 year. Conclusions: These results suggest that simple application of impermeable cover without any strict management plan provide incomplete but significant reduction to allergen exposure and clinical benefits.