Continuous avoidance measures with or without acaricide in dust mite-allergic asthmatic children. Clinical evaluation of a double-blind dust-mite avoidance trial with mite-allergic rhinitic patients. House dust mite allergen avoidance and self-management in allergic patients with asthma: randomised controlled trial. House dust mite avoidance for children with asthma in homes of low-income families. Allergen avoidance in house dust mite sensitive adult asthma. Allergen-avoidance measures in homes of house-dust-mite-allergic asthmatic patients: effects of acaricides and mattress encasings. The respiratory effects of reduction of mite allergen in the bedrooms of asthmatic children--a double-blind controlled trial. Allergic rhinitis due to house dust mites: evaluation of the efficacy of specific sublingual immunotherapy. A randomized controlled trial of mite allergen-impermeable bed covers in adult mite-sensitized asthmatics.
Improvement in the quality of life in the Western world and increased time spent indoors by children have enhanced the spread of house dust mites and increased the exposure time for sensitive children. Also, exposure to house dust mites in infancy and subsequent development of childhood asthma have been clinically linked. Recently, new acaricides have been developed.
                To test the efficacy of the new acaricide (esdepallethin and piperonyl butoxide--"Acardust") combined with environmental control compared with continuous house dust mite avoidance measures.
                Forty-six house dust mite-allergic, asthmatic children were evaluated for 6 months in a prospective, randomized, double-blind, and placebo-controlled study. Patients were randomly allocated to active and placebo acaricide treatment combined with avoidance measures, whereas only continuous avoidance measures were taken in the third group. Symptom score, medication usage, and peak flow measurements were recorded daily. The amount of house dust mite allergen in the dust vacuumed from the bedrooms was also measured.
                Morning and evening peak expiratory flow rates and forced expiratory volume in one second remained unchanged throughout the study period. In all groups, the symptom scores improved significantly, whereas the amount of house dust mite allergen decreased significantly at the end of the trial.
                Continuous house dust mite avoidance measures have a significant positive effect on the symptomology of children with mild or moderate asthma. "Acardust" combined with continuous house dust mite avoidance measures is not more effective than continuous house dust mite avoidance measures alone in the treatment of house dust mite-allergic, asthmatic children. Inheritance and allergen exposure are key factors in the development and the course of atopic allergy, expressed as conjunctivitis, rhinitis, asthma or dermatitis. This study concerns the clinical significance of mite and mite-allergen avoidance measures based on intensive cleaning with acaricide (solidified benzylbenzoate) added (10 dwellings), and without biocidal activity (10 other homes) as a control in a double-blind trial with matched pairs. Twenty subjects with persisting rhinitic complaints were selected. They lived in 20 different dwellings and were all sensitized to pyroglyphid mites; 12 of them were also sensitized to stored product mites (Acari). Daily symptoms and medication score, guanine and dust exposure, total and mite-specific IgE in serum, eosinophilia in the blood and in the nasal smear, intracutaneous tests with house dust mite and storage mite extracts were compared in both pairs and groups. Acarological data, physiochemical aspects and exposure assessment are discussed in detail elsewhere. Symptom scores dropped significantly, as did the total IgE and exposure to dust and mite products in the acaricidal cleaner treatment group. After 1 year, the daily symptoms median was 47% (P = 0.025), total IgE was 38% (P = 0.0049), and exposure to dust and mite products (guanine exposure) was 53% (P = 0.0449) better or lower than in the controls. Intensive cleaning, without acaricidal treatment performed twice a year, resulted in clinical improvement in four out of 10 subjects, of whom none became free of complaints. In the Acarosan treatment group (cleaning + benzylbenzoate) eight out of 10 subjects improved, in three cases subjective symptoms disappeared.(ABSTRACT TRUNCATED AT 250 WORDS) The efficacy of bed covers that are impermeable to house dust mites has been disputed.
                The aim of the present study was to investigate whether the combination of 'house dust mite impermeable' covers and a self-management plan, based on peak flow values and symptoms, leads to reduced use of inhaled corticosteroids (ICS) than self-management alone.
                Prospective, randomised, double blind, placebo-controlled trial.
                Primary care in a south-eastern region of the Netherlands.
                Asthma patients aged between 16 and 60 years with a house dust mite allergy requiring ICS were randomised to intervention and placebo groups. They were trained to use a self-management plan based on peak flow and symptoms. After a 3-month training period, the intervention commenced using house dust mite impermeable and placebo bed covers. The follow-up period was 2 years. Primary outcome was the use of ICS; secondary outcomes were peak expiratory flow parameters, asthma control, and symptoms.
                One hundred and twenty-six patients started the intervention with house dust mite impermeable or placebo bed covers. After 1 and 2 years, significant differences in allergen exposure were found between the intervention and control groups (P<0.001). No significant difference between the intervention and control groups was found in the dose of ICS (P = 0.08), morning peak flow (P = 0.52), peak flow variability (P = 0.36), dyspnoea (P = 0.46), wheezing (P = 0.77), or coughing (P = 0.41). There was no difference in asthma control between the intervention and control groups.
                House dust mite impermeable bed covers combined with self-management do not lead to reduced use of ICS compared with self-management alone. Home exposure to high levels of house dust mite allergen has been shown to aggravate airways reactivity and asthma.
                The purpose of this study was to determine whether specific house dust mite control measures could reduce exposure levels and asthma severity.
                This double-blinded, randomized trial compared asthma progression over 1 year in children whose homes received standard environmental control intervention with those whose homes received aggressive intervention for dust mite elimination. The primary end point was doubling in PD20 methacholine.
                Symptom scores and quality-of-life scores were similar for the standard and aggressive intervention groups. PD20 methacholine doubling occurred in 9 members of the aggressive intervention group vs 4 control patients (P <.05). Dust mite levels decreased in the aggressive intervention homes compared with the standard intervention homes (P <.05).
                Aggressive dust mite intervention decreased dust mite levels and improved bronchial hyperresponsiveness. Fifty adult asthmatic patients with strongly positive skinprick tests to the house dust mite were admitted into a prospective randomised controlled trial of house dust mite avoidance in the community. Twenty-two of the experimental group completed one year of dust avoidance and 19 of these tolerated the use of plastic mattress and pillow covers. Twenty of the control group (who did not alter their housecleaning habits) also completed one year of study. A fall in mite and dust levels was noted in the homes of the experimental but not the control group. Fifteen of the experimental group who completed the study were strongly RAST positive (score 3 or more) to the house dust mite. These patients had a significant improvement in FEV1/FVC, PEFR, PC20, use of treatment, and symptom score at one year, whilst the seven experimental patients who were not strongly RAST positive (score 2 or less) did not, suggesting that the change noted in the former patients was not merely due to a placebo effect. Fifteen of the control group who completed the study were also strongly RAST positive for the house dust mite and these patients showed no change in any of the parameters. This study demonstrates that adult asthmatic patients can successfully carry out house dust eradication procedures in the community over a long period of time, and that those patients who are allergic to the house dust mite appear to have both subjective and objective improvement in their asthma. This double-blind, placebo-controlled study investigated whether the application of an acaricide (Acarosan) on mattresses and on textile floor coverings in living rooms and bedrooms can contribute to improvement in lung function and airway hyperresponsiveness in 40 adult asthmatic patients sensitized to house-dust mite. In a second group of 19 patients who refused chemical intervention, the clinical effects of application of allergen-impermeable mattress encasings were studied. In all three treatment groups, Der p 1 levels in mattress dust were statistically significantly decreased after 12 months. However, this decrease was much greater in the group who received mattress encasings (final mean level 430 ng/g) than in groups with acaricide- or placebo-treated mattresses (final mean levels 1730 and 2100 ng/g, respectively). Treatment of textile floors with either Acarosan or placebo chemical caused a statistically significant decrease in the level of the house-dust-mite allergen Der p1 in floor dust. In the group with mattress encasings, no significant changes of floor dust Der p 1 were found. Airway hyperresponsiveness (as measured by the PC20 histamine) improved significantly in the mattress cover group after 6 months. The Acarosan group also showed a small but statistically significant improvement after 12 months. Inhalation of house dust mite (HDM) allergen may provoke attacks of asthma.
                We investigated whether a double-blind placebo-controlled community-based study aimed at reducing the HDM allergens in the bedrooms of HDM sensitive asthmatic children using the best methods available would prove beneficial to the children's health.
                The children (mean age 9.9 years, 34 boys) were recruited by a questionnaire submitted to 7386 families in a geographically-defined area of the UK. Subjects were chosen to take part in the double-blind placebo-controlled trial if they were asthmatic, skin sensitive to mites, and had mite allergen in their mattresses. Seventy children were randomly allocated to groups. In the active group, the children's bedrooms were treated with an acaricide (Acarosan) and the mattresses, pillows and duvets were encased in exclusion covers. The control group received placebo treatments.
                Forty-nine complete data sets were obtained. Applying bedding covers and Acarosan led to a median reduction of 480 ng (100%) in mite allergen on the mattress vs 215 ng (53%) reduction in placebo-treated group by 6 weeks. No evidence was found that the acaricide reduced mite allergen level. A change in bronchial reactivity to histamine was observed in the children after 6 weeks. This was not associated with any change in thrice-daily records of peak expiratory flow rate. By 24 weeks, the actively-treated children had improved forced expiratory volume in 1s (FEV1) and fewer required bronchodilator therapy or reported asthmatic symptoms than did the controls.
                The results suggest that mite removal procedures may modestly improve mite-sensitive asthmatics and could perhaps be of value in exceptionally mite-sensitive and/or highly mite-exposed individuals whose response to the attempted removal should be measured. The efficacy and safety of sublingual immunotherapy (SLIT) in patients with chronic rhinitis related to sensitization to house dust mites are still controversial.
                After application of an anti-mite mattress cover, patients were only included in the study when the cumulative symptom score over a fortnight was greater than 70 out of a possible total of 168. Thirty-two of the 120 patients selected were randomized to receive SLIT for 2 years: 17 received placebo and 15 received the Dermatophagoides pteronyssinus and D. farinae 50/50 allergen extract.
                Significant between-group differences were observed after 1 year and persisted at the end of the second year for the rhinitis total score (P < 0.02), blocked nose score (P < 0.01) and nasal itching score (P < 0.01). Skin reactivity to house dust mites was significantly reduced in the group receiving house dust mite extract (P < 0.03). No statistical difference was observed between the two groups for medication scores, but a low medication consumption was observed in all patients. No serious and no systemic adverse reactions were reported.
                This study indicates the superiority of active treatment vs. placebo, evaluated on efficacy criteria (rhinitis score) or objective criteria (skin reactivity). The availability of a solid form (tablet) could represent a progress in terms of patient acceptability. Mite-allergic patients with allergic disease should benefit from avoiding mite allergens. Many physicians, however, are yet to be convinced that allergen avoidance can make a significant contribution to asthma management in these patients. Many allergen-avoidance regimes include multiple measures of allergen reduction, but as mite exposure in the home is most likely to be greatest in bed dust, bedding is usually the first target for intervention.
                This study selected adult patients considered to be most likely to benefit from avoiding mite allergens, namely diagnosed asthmatics, sensitized to house dust mites and exposed to mite allergen in their mattresses. Patients were randomized into a placebo-controlled trial of the use of allergen-impermeable bed covers for 12 months, without any other form of mite-reduction measures.
                Adults with asthma were selected from general practices and asthma clinics in south-east London. Their serum IgE to mite allergens and allergen content of mattress dust samples were measured. Those with >0.70 kU/L mite-specific IgE and >2 microg/g Der p 1 were randomized into active or placebo treatments. Information was collected on allergic symptoms and medication use and quarterly peak flow diaries were kept throughout the trial. Dog or cat allergic patients were excluded if they had a pet at home to which they were sensitized.
                The mean decrease in microg/g Der p 1 was 25.7 (95% CI 8.9, 74.1) in the active group and 4.5 (95% CI 1.8, 11.5) in the placebo group. Der p 1 concentrations in the active and placebo groups at the end of the trial were not significantly different. There was no effect on peak flow or asthma symptoms in a simple comparison of the treatment and placebo groups.
                In this group of patients, mite allergen avoidance in the bed by the use of allergen-impermeable bedding alone cannot be recommended as an effective way of relieving asthma symptoms.
Chemical and physical methods aimed at reducing exposure to house dust mite allergens cannot be recommended. It is doubtful whether further studies, similar to the ones in our review, are worthwhile. If other types of studies are considered, they should be methodologically rigorous and use other methods than those used so far, with careful monitoring of mite exposure and relevant clinical outcomes.