Double-blind placebo-controlled house dust mite control measures in adult patients with atopic dermatitis

Background Avoidance of allergens has been shown to be of benefit in patien ts with atopic asthma sensitized to indoor allergens. In atopic dermatitis, there is so far little information about the effect of house dust mite eli mination strategies. Objectives We therefore performed a randomized controlled study of house du st mite control in patients with this disease. Methods Twenty adult patients with moderate to severe atopic dermatitis wer e included. Inclusion criteria were a positive RAST to house dust mite anti gen (CAP class > 3) and a concentration of > 2 mug g(-1) of the house dust mite antigen Der p1 in the patient's mattress dust. Patients were randomize d to either the active treatment group (allergen-impermeable mattress encas ing, acaricide spray containing tannic acid and benzylbenzoate) or a contro l group (allergen-permeable encasing, spray containing water and traces of ethanol). Severity of disease was estimated every 2 months by an establishe d score (SCORAD), and eosinophil cationic protein (ECP) in the serum was de termined by enzyme-linked immunosorbent assay. Furthermore, the use of topi cal steroids was quantified. Patients assessed daytime pruritus and pruritu s-induced sleeplessness weekly on a visual analogue scale. The study lasted 1 year. Results At the end of the study, the active treatment group showed a statis tically significant reduction in Der p1 exposure as compared with the contr ol group. However, when comparing the change from the start to the end of t he study, there was no statistically significant difference between active treatment and control groups as measured by the SCORAD score and by ECP lev els in the serum. Some patients in the active treatment group reported less pruritus-induced sleeplessness, but there was no statistically significant difference between the two treatment groups. Conclusions For adult patients with atopic dermatitis it was shown that 1 y ear of house dust mite avoidance reduced the allergen exposure, but an impr ovement of overall disease activity was not demonstrated.