Mite elimination - clinical effect on eczema

Allergic reactivity to house-dust mites (HDM) can be detected in patients w ith atopic eczema by prick and patch test challenge. To determine the clini cal relevance of this reactivity, we performed a placebo-controlled, double -blind trial of anti-HDM measures. Active treatment comprised Cortex bags f or all the bedding elements, a high-powered vacuum cleaner, and a spray con taining benzyl alcohol and tannic acid to kill mites and denature allergens . Placebo treatment was light cotton bags, a cheap vacuum cleaner, and wate r spray. Forty-eight patients (28 active group) completed the trial, which lasted 6 months. Dust was sampled from the mattress surface and bedroom and living-room carpets before and at monthly intervals after institution of t he measures. Dust was weighed and Der p 1 determined by ELISA (ALK). Patien ts were assessed for area and severity of eczema by a blinded observer. The re was a highly significant reduction in bed surface dust - most beds yield ed insufficient dust to extract and assay. Carpet Der p 1 levels were reduc ed to similar minimal levels by both active and placebo treatments (about 2 50 ng/m(2)). There were highly significant benefits on the eczema scores, t he active treatment being greatly superior to placebo (P < 0.0006; analysis of covariance). In conclusion, Gortex bed bags were highly effective at co ntaining dust within the bed. This was associated with clinical improvement in most patients with atopic eczema - the biggest improvements were seen i n the most severely affected subjects. (The results of this study have been published [Lancet 1996;347:15-181].).