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. Environmental controls in reducing house dust mites and nasal symptoms in patients with allergic rhinitis. Three-year outcomes of dietary fatty acid modification and house dust mite reduction in the Childhood Asthma Prevention Study. Preventive measures in mite asthma. A controlled trial. House-dust-mite sublingual-swallow immunotherapy (SLIT) in perennial rhinitis: a double-blind, placebo-controlled study. Double-blind placebo-controlled study of sublingual immunotherapy with house dust mite extract (D.pt.) in children. House dust mite allergen avoidance: a randomized controlled trial of surface chemical treatment and encasement of bedding. Effects of house dust mite avoidance measures on Der p 1 concentrations and clinical condition of mild adult house dust mite-allergic asthmatic patients, using no inhaled steroids. Effect of application of benzyl benzoate on house dust mite allergen levels. House dust mite barrier bedding for childhood asthma: randomised placebo controlled trial in primary care [ISRCTN63308372]. House dust mite allergen reduction and allergy at 4 yr: follow up of the PIAMA-study. An evaluation of mattress encasings and high efficiency particulate filters on asthma control in the tropics. House dust mite allergen levels and an anti-mite mattress spray (natamycin) in the treatment of childhood asthma. [The efficacy of controlling of house dusts in attacks of mite sensitive asthmatics]. Mechanical ventilation and high-efficiency vacuum cleaning: A combined strategy of mite and mite allergen reduction in the control of mite-sensitive asthma. Effect of house dust mite avoidance measures on adult atopic asthma. Effective education of adults with asthma who are allergic to dust mites. Accumulation of house-dust mite (Der-p-1) levels on mattress covers. The effects of a single treatment of an acaricide, Acarosan, and a detergent, Metsan, on Der p 1 allergen levels in the carpets and mattresses of asthmatic children. Efficacy of an air-cleaning device equipped with a high efficiency particulate air filter in house dust mite respiratory allergy. Double blind trial of ionisers in children with asthma sensitive to the house dust mite. Eradication of house dust mite from homes of atopic asthmatic subjects: a double-blind trial. Allergen reduction measures in houses of allergic asthmatic patients: effects of air-cleaners and allergen-impermeable mattress covers. A double blind controlled trial of Bencard house dust mite (Migen) hyposensitisation in Zambian asthmatics. The effect of high-efficiency and standard vacuum-cleaners on mite, cat and dog allergen levels and clinical progress. A 1-year, placebo-controlled, double-blind house-dust-mite immunotherapy study in asthmatic adults. Efficacy of the acaricide: acardust for the prevention of asthma and rhinitis due to dust mite allergy, in children. Clinical effectiveness of a mite allergen-impermeable bed-covering system in asthmatic mite-sensitive patients. House-dust mite sublingual-swallow immunotherapy in perennial conjunctivitis: a double-blind, placebo-controlled study. The effect of anti-allergic mattress encasings on house dust mite-induced early- and late-airway reactions in asthmatic patients. A double-blind, placebo-controlled study. Clinical effects of benzyl benzoate in the prevention of house-dust-mite allergy. Results of a prospective, double-blind, multicenter study. Control of exposure to mite allergen and allergen-impermeable bed covers for adults with asthma. Reducing domestic exposure to dust mite allergen reduces bronchial hyperreactivity in sensitive children with asthma. A double-blind, placebo controlled trial of solidified benzyl benzoate applied in dwellings of asthmatic patients sensitive to mites: clinical efficacy and effect on mite allergens. Immunotherapy in children with allergic asthma: effect on bronchial hyperreactivity and pharmacotherapy. Effect of improved home ventilation on asthma control and house dust mite allergen levels. Benzyl-benzoate foam: effects on mite allergens in mattress, serum and nasal secretory IgE to Dermatophagoides pteronyssinus, and bronchial hyperreactivity in children with allergic asthma. Effect of a bed covering system in children with asthma and house dust mite hypersensitivity. Anti-mite measurements in mite-sensitive adult asthma. A controlled trial.
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. A randomized comparison group pretest-posttest experimental design was used to quantitatively determine the effects of environmental control measures on patients with allergic rhinitis. Environmental controls included wrapping the mattress with a vinyl cover, washing the top bedding cover with 55 degrees C hot water every two weeks, removal of soft furniture, and wet cleaning of the bedroom floor every day. Thirty subjects were randomly assigned to experimental and control groups. The amount of house dust mites in dust samples collected from the bedroom floor, bedding and mattress, as well as the nasal symptoms of patients, were measured twice at one-month intervals. A significant decrease in house dust mites in dust samples and relief in patients' nasal symptoms were observed in the experimental group who had environmental controls. Two factors thought to influence the risk of asthma are the promoting effect of sensitization to house dust mites and the preventive effect of increased omega-3 fatty acids. Although house dust mite allergen avoidance has been used as a preventive strategy in several trials, the effect of omega-3 fatty acid supplementation in the primary prevention of asthma and allergic disease is not known.
                To measure the effects of dietary supplementation with omega-3 fatty acids and house dust mite allergen avoidance in children with a family history of asthma.
                A total of 616 children at high risk of asthma were enrolled antenatally in a randomized controlled trial, and 526 children remained in the trial at age 3 years. The outcomes were symptoms of allergic disease and allergen sensitization.
                There was a significant 10.0% (95% CI, 3.7-16.4) reduction in the prevalence of cough in atopic children in the active diet group ( P=.003; number needed to treat, 10) but a negligible 1.1% (95% CI, -7.1 to 9.5) reduction cough among nonatopic children. There was a 7.2% (95% CI, 10.11-14.3) reduction in sensitization to house dust mite in the active allergen avoidance group ( P=.05; number needed to treat, 14). No significant differences in wheeze were found with either intervention.
                These results suggest that our interventions, designed to be used in simple public health campaigns, may have a role in preventing the development of allergic sensitization and airways disease in early childhood. This offers the prospect of reducing allergic disease in later life. To evaluate the effect of preventive measures 46 patients, all allergic to house-dust mites (Dermatophagoides spp.), were randomly allocated to a study and a control group. According to the patients' subjective recordings of symptom score and use of medicine, compared with the control group, the study group had improved. There was, however, no improvement when comparing the objective recordings of morning and evening peak flow and use of medicine, and it is concluded that the preventive measures in this programme are not very effective for patients allergic to house-dust mites. The reduction in indoor humidity in the study group was limited and, as a high indoor humidity is the cause of huge populations of house-dust mites in homes, it is emphasized that future programmes of preventive measures should focus more on damp problems, particularly those related to bad housing construction. The safety and efficacy of sublingual-swallow immunotherapy (SLIT) in rhinitis caused by house-dust mite were evaluated in a double-blind, placebo-controlled study including 75 patients for 24 months.
                Patients received either placebo or SLIT with a standardized Dermatophagoides pteronyssinus (D.pt.) - D. farinae (D.f) 50/50 extract. The mean cumulative dose was 90,000 IR, equivalent to 2.2 mg of Der p 1 and 1.7 mg of Der f I. Symptom and medication scores were assessed throughout the study. Exposure to house-dust mite, skin sensitivity, and serum specific IgE and IgG4 were assessed before starting treatment and after 12 and 24 months.
                Seventy-two patients (36 active-36 placebo) were eligible for intent-to-treat analysis. Thirty-six patients dropped out of the study. The number of patients who dropped out due to lack of efficacy was eight out of 37 (21.6%) in the active treatment group compared to 15 out of 38 (39.5%) in the placebo group (chi-square=2.81, P=0.09). Total symptom and medication scores decreased significantly after 12 and 24 months (P<0.05) of treatment in both groups, but no significant difference was observed between the active and placebo groups. After 24 months, the number of patients with high levels of indoor allergenic load decreased significantly in both groups compared to baseline data (P=0.01). Specific IgE (D.pt. and D.f.) increased significantly in the active treatment group after 12 and 24 months, while no change was observed in the placebo group. Specific IgG4 levels were not significantly modified in either group. Two patients in each group reported mild adverse effects. No severe adverse effects were reported.
                We conclude that SLIT in rhinitis caused by house-dust mite was safe, but there was a lack of consistent clinical benefit compared to placebo, probably due to the impact of the allergen avoidance measures that lowered the allergen burden. Safety and efficacy of sublingual (sublingual-swallow) immunotherapy (IT) with house dust mite extract were evaluated in 30 children (6-15 2/3 years of age) over the first 12 months of an ongoing study. The cumulative dose was 570 micrograms Der p I (five times that administered with subcutaneous therapy). Safety: One patient on active treatment dropped out after 8 weeks because of a subjective feeling of severe weakness, questionably induced by the therapy. Five patients on active therapy and one patient on placebo reported minor local side effects. Efficacy: Pulmonary symptoms were reduced after 12 months in actively treated asthmatics, but this was not consistent with the lack of improvement in bronchial reactivity, skin sensitivity and specific IgG and IgG4 against D.pt. in this group. In patients with rhinitis nasal sensitivity was reduced in the placebo group without concomitant improvement in the nasal symptom score. Specific IgE (D.pt. and D.f.) increased significantly more in the active treatment group after 3 and 12 months. We conclude that sublingual IT over 12 months with the fivefold Der p 1 dose of subcutaneous IT was well tolerated, but there was no consistent clinical or immunological benefit compared to placebo. 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 10.2 micrograms Der p I/g of fine dust, and, in the placebo group 25.7, 11.8 and 6.3 micrograms/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).(ABSTRACT TRUNCATED AT 250 WORDS) Exposure to house dust mite (HDM) allergens often results in worsening of asthma. Therefore, avoidance of exposure to HDM allergens is often proposed. Unfortunately, the most effective and feasible avoidance strategy is still not completely assessed. Consequently, we investigated the effects of a combined HDM avoidance strategy on HDM allergen concentrations and clinical condition of allergic, mild asthmatic, patients using no inhaled steroids.
                Asthmatic patients, allergic to HDM, using no inhaled corticosteroids, were randomly allocated to an active (n = 76) or a placebo allergen-avoidance group (n = 81). Avoidance measures consisted of applying Acarosan(R) (placebo: water) to the living room and bedroom floors, and the use of HDM-impermeable covers for mattresses and bedding (placebo: cotton covers for mattresses only). Effects on allergen concentrations (Der p 1), FEV1, bronchial hyperresponsiveness, peak flow parameters and asthma symptom scores were studied during 20 weeks and controlled for the allergic status of the patients.
                The active covers reduced Der p 1 concentrations to 9.4% (P = 0.0001), and were always significant lower than in the placebo group (P = 0.0002). Acarosan(R) resulted in slight but significant decreases (twofold, P = 0.0001), both on living room and bedroom floors, but concentrations were never significantly lower than the placebo group. Although the combined avoidance strategy resulted in a considerable reduction in allergen load in the active group, no differences were seen between the two groups in any of the clinical parameters during the follow-up period in this group of allergic asthmatics, using no inhaled corticosteroids. Corrections for the allergic status did not alter these results.
                The combined avoidance strategy was effective in reducing HDM allergen concentration. This was especially achieved by the allergen-impermeable covers, while the effects of Acarosan(R) were only marginal. However, this allergen reduction was not reflected in a convincing improvement in clinical condition in this group of mild allergic asthmatics, using no inhaled steroids. Perhaps, a longer follow-up period would have resulted in more pronounced effects. Several acaricides have become available for reducing house dust mite allergen levels.
                The purpose of this study was to assess whether the use of benzyl benzoate (Acarosan) provides additional benefit to the usual mite control measures including encasement of mattress and pillows with vinyl covers.
                A randomized controlled trial was carried out in 26 homes (14 control versus 12 treatment) of asthmatic patients in two cities (Vancouver and Winnipeg). The control group had the usual house dust mite control measures including the use of vinyl covers for mattresses and pillows while the treatment group had application of benzyl benzoate to mattresses and carpets in the bedroom and the most commonly used room, in addition to the above control measures. Mite allergen levels were measured 3 months and immediately before, 1 week, and 1 and 3 months after the application of house dust mite control measures. Patients kept diary cards on asthma symptoms and peak expiratory flow rates morning and evening one month before and three months after the onset of mite allergen control measures.
                A reduction of mite allergen level was found in mattress samples in both groups, statistically significant at all times in the treatment group and at one and three months in the control group. Mite allergen levels on floor carpets also showed progressive reduction in both groups, but were significantly different in the treatment group (compared with controls) at 1 week, and were lower compared with baseline in the treatment group up to 3 months. No significant changes in asthma symptoms, peak expiratory flow rates, spirometric measurements, or bronchial hyperresponsiveness were observed among treatment or control group subjects.
                The addition of benzyl benzoate to conventional house dust mite control measures resulted in a significant reduction in floor carpet dust mite levels that persisted for 3 months. The results of this study should be confirmed in a larger and longer study. The house dust mite is the most important environmental allergen implicated in the aetiology of childhood asthma in the UK. Dust mite barrier bedding is relatively inexpensive, convenient to use, and of proven effectiveness in reducing mattress house dust mite load, but no studies have evaluated its clinical effectiveness in the control of childhood asthma when dispensed in primary care. We therefore aimed to evaluate the effectiveness of house dust mite barrier bedding in children with asthma treated in primary care.
                Pragmatic, randomised, double-blind, placebo controlled trial conducted in eight family practices in England. Forty-seven children aged 5 to 14 years with confirmed house dust mite sensitive asthma were randomised to receive six months treatment with either house dust mite barrier or placebo bedding. Peak expiratory flow was the main outcome measure of interest; secondary outcome measures included asthma symptom scores and asthma medication usage.
                No difference was noted in mean monthly peak expiratory flow, asthma symptom score, medication usage or asthma consultations, between children who received active bedding and those who received placebo bedding.
                Treating house dust mite sensitive asthmatic children in primary care with house dust mite barrier bedding for six months failed to improve peak expiratory flow. Results strongly suggest that the intervention made no impact upon other clinical features of asthma. Exposure to high allergen levels in early life is a risk factor for the development of allergy. We previously reported limited effects of mite allergen impermeable mattress covers in the prevention and incidence of asthma and mite allergy (PIAMA) cohort at the age of 1 and 2 yr. We now present the results of follow-up at 4 yr objectives. To examine the effects of early reduction of house dust mite (HDM) allergen exposure by means of mattress covers on the incidence of allergy and asthma symptoms in the PIAMA birth cohort at the age of 4 yr. High-risk children (allergic mother) were prenatally recruited and randomly allocated to three groups; receiving mite allergen impermeable mattress covers (n = 416), placebo covers (n = 394) or no intervention (n = 472). At 4 yr of age, atopy was assessed by questionnaire; specific Immunoglobulin E (IgE) to inhalant and food allergens was measured in serum. Dust samples collected from the children's mattresses were analysed for mite allergens. Dermatophagoides farinae1 allergen (Der f 1) levels in dust were reduced in the active group. However, Dermatophagoides pteronissinus 1 (Der p 1) levels, sensitization and atopic symptoms were similar in all groups. We found no effect of mite allergen impermeable mattress covers on sensitization and atopy at 4 yr. Moreover, the allergen reducing effects of the covers had disappeared for one of the two mite allergens that were measured. The effect of two allergen avoidance modalities, Allergy Control Covers (ACC) and High Efficiency Particulate Filters (HEPA) on asthma control in children were evaluated. This was an open study involving 24 dust mite sensitive asthmatic children. Following a 4 week run-in period, the subjects were randomly allocated to use mattresses fitted with ACC (n = 6), HEPA filters in their bedrooms (n = 12) or act as controls (n = 6) for a study duration of 4 months. Measurements of the major Dermatophagoides spp. mite allergens, Der p 1 and Der f 1, levels in dust samples obtained from mattresses were made at baseline, 1, 2 and 4 months post implementation. Daily symptom scores including morning and evening peak flow readings, and monthly spirometry and exercise bronchoprovocation tests were carried out Our results showed that dust mite allergen levels in mattresses fell at 1 and 2 months post implementation in the ACC group (p<0.05). In contrast, no decrease in allergen levels was seen in the HEPA and control group. At the end of the 16 weeks, only the ACC group showed improvement in FEV1 and reduction in diurnal peak expiratory flow rate (p<0.05). Improvement in mean symptom scores was also observed for both the ACC and HEPA groups, but not the control groups (p<0.05). Although the numbers in this study were small, the results Indicate that the effectiveness on mite exposure barrier covers was short-lived, and the improvement in asthma control though documented was not obvious. Natamycin, a fungicide marketed as Tymasil, is claimed to reduce house dust mite numbers and would therefore be expected to improve asthma in children with mite sensitivity. We have tested this assertion by a double-blind, placebo-controlled trial. There was no significant effect on levels of Der p I in mattress dust between active and placebo groups at the end of the spraying period. Histamine inhalation challenge PC20, clinic visit symptom scores and lung function tests reflecting either large or small airways obstruction were also unchanged. Therefore this product is not a therapeutic option for mite-allergic patients using the manufacturer's recommended dose and method of administration. Other factors influencing the Der p I levels were also investigated. Of these, only month of measurement and bedroom wall humidity showed any association. To study the effect of controlling of house dusts in attacks of mite sensitive asthmatics (DMSA).
                Dust in mattresses, sofas, beddings and pillows were calculated for 43 cases of DMSA every season meanwhile the asthmatic symptoms, amount of drugs taken, PEF value in morning and evening were daily recorded by patients, then the patients were divided into two groups i.e. treatment group (A group, 22 cases) and no treatment group ( B group, 21 cases) randomly. The controlling measures included well-ventilation, washing clothes and bedclothes and catching dust frequently and exposing of clothing or bedclothes in the sun.
                Correlation was found between house dust density and asthmatic attacks. The number of dust mites was lower after treatment than before in A group [(N/g): spring 62 vs 103, summer 105 vs 132, autumn 163 vs 231, winter 9 vs 13]. Concomitant asthmatic symptoms and amount of drugs taken and total IgE reduced [(0.6 vs 1.6) mg/L] and PEF values or PEF difference improved.
                Control of dust mites growth could alleviate the asthmatic symptoms and decrease the attacks. The relationship between exposure to house dust mite (HDM) allergens and prevalence of sensitization to these allergens in patients with asthma has been confirmed in many studies. Mite population growth is regulated by humidity. Reducing humidity and removing allergen by efficient vacuuming should control mite allergen and reduce symptoms.
                We sought to investigate the effect of mechanical ventilation and high-efficiency vacuuming on HDM numbers and Der p 1 concentrations in the homes of mite-sensitive asthmatic subjects and to evaluate the effect of any reductions on symptoms.
                The homes of 40 HDM-sensitive asthmatic subjects were randomized to receive (1) mechanical ventilation and a high-efficiency vacuum cleaner (HEVC); (2) mechanical ventilation alone; (3) an HEVC alone; and (4) no intervention. Homes and patients were monitored for 12 months. Change in absolute humidity, mite numbers, Der p 1 concentrations, lung function, bronchial hyperresponsiveness, and symptom scores were analyzed.
                Homes with mechanical ventilation achieved significantly lower humidity levels than those without (P <.001), with an associated reduction of mite numbers (P <.05) and Der p 1 concentrations (P <.001 ¿in nanograms per gram, P =.006 ¿in milligrams per square meter) in bedroom carpets and some other mite sources in the ventilated areas of the homes. The addition of a vacuum cleaner enhanced this effect. There was a trend for an improvement in histamine PC(20) (P =.085) in the patients whose homes were ventilated.
                The use of a mechanical ventilation system in suitable homes resulted in some reduction in numbers of HDM and Der p 1 concentrations. The addition of an HEVC slightly enhanced the effect but not sufficiently to see an improvement in symptoms. Twenty one adult patients with asthma, with positive skin test responses to the European house dust mite, Dermatophagoides pteronyssinus, were randomly allocated to a control group or to a group applying house dust mite avoidance measures. These included an initial application of liquid nitrogen to mattresses and bedroom carpets to kill the live house dust mite population. Histamine airway responsiveness, symptom scores, peak expiratory flow rates (PEF), and house dust mite numbers were determined during the two week pretrial and eight week trial periods. Nine patients in each group completed the study. By the end of the study there was a significant reduction in live mites in the "avoidance" group but not in the control group. The avoidance group showed a significant improvement in symptom scores measured on a linear analogue scale, in the number of hours each day spent wheezing (mean reduced from 8.6 to 4.5 hours), and in PEF (l/min) both in the morning (from 364 to 388) and in the evening (from 368 to 392). These changes were not found in the control group. The provocative concentration (PC) of histamine causing a 20% fall in FEV1 (PC20FEV1) had increased significantly in the avoidance group at eight weeks (from 0.58 to 2.3 mg/ml), whereas no change was seen in the control group (from 0.93 to 1.21 mg/ml). These results show that house dust mite avoidance, combined with initial killing of the mite by liquid nitrogen, diminishes airway responsiveness and improves asthma symptom control over an eight week period in adult asthmatic patients with house dust mite allergy. The effects of supplementary computer instruction in house dust mite-avoidance measures on adherence to implementing measures, on home dust mite-allergen levels, and on symptomatology were investigated in 52 adult patients with mite-associated asthma. Twenty-six patients received conventional instruction (counseling and written instruction) and the other 26 patients received conventional plus 22 minutes of interactive computer-assisted instruction. Instructions were aimed at mite-avoidance measures. Pre- and postinstruction dust samples were collected, and adherence was monitored. All patients kept symptom diaries twice a day. Patients' progress was followed for 12 weeks, and all patients completed the study. Adherence, number of observed and self-reported mite-avoidance measures implemented after visit, was higher for the computer group (p = 0.023). The computer-instructed group achieved significantly lower levels of mite allergen in bedroom carpets (p = 0.004) with mean levels of mite allergen declining from 6.5 +/- 7.6 to 2.2 +/- 4.3 micrograms/gm of dust (two-site monoclonal antibody assays), whereas levels for the conventional-instructed group did not change. Moreover, by study weeks 9 and 10, the computer-instructed group was significantly less symptomatic (p = 0.033). Mean symptom scores for this group decreased from 12.4 to 7.7, compared with 16.4 to 14.3. Conventional instruction supplemented with computer instruction is suggested in mite education. Mattresses serve as a large reservoir for house-dust mite antigens and harbour the highest mite levels within the household. Mite reduction measures have previously been shown to be unsuccessful. The effect of mattress covers and acaracides on Der-p-1 levels in the mattresses of 60 patients with mite-allergic asthma was studied. Der-p-1 levels were measured using monoclonal antibodies (ELISA method). Baseline levels were recorded and re-assessed at 8-week intervals over a 6-month period. Patients were randomised into three equal groups. In group A mattresses were treated with Metsan (Snowchem) and benzylbenzoate only; group C had their mattresses covered with mattress covers (Allergy Control Products). Group B was the control group. We were unable to demonstrate any reduction of mite levels in the beds of all 3 groups. In fact all 3 groups demonstrated an increase in Der-p-1 levels over the study period, viz. group A (mean pre: 14.28, post: 34.18 micrograms/g dust); group C (mean pre: 8.26, post: 20.80 micrograms/g dust) and group B (mean pre: 18.21, post 38.47 micrograms/g dust). However, 12 patients in group C had their mattress covers washed in hot water at weekly intervals over a 5-week period at the end of the study. The results demonstrated a significant reduction in mite levels (mean pre: 41.95, post: 26.2 micrograms/g dust; P = 0.027). We therefore conclude that the use of mattress covers per se does not reduce Der-p-1 levels. The regular application of benzylbenzoate and Metsan does not prevent the accumulation of Der-p-1 on mattresses either.(ABSTRACT TRUNCATED AT 250 WORDS) Baseline levels of the house-dust mite allergen, Der p 1, were measured on the carpets and mattresses of 60 pure-mite-sensitive asthmatic children in the Cape Peninsula, by means of an enzyme-linked immunosorbent assay (ELISA). High levels of mite allergens were recorded (range 2-50 micrograms Der p 1/g dust). In order to investigate the efficacy of the application of acaricides to carpets and bedding, 3 groups of 20 children were studied. Carpets and mattresses in group A were treated with a detergent, Metsan (Snowchem), and in group B with Metsan combined with the acaricide, Acarosan (Noristan). Group C was a control group in which no treatment was applied. The level of airway hyperreactivity (PC20) to histamine was measured at the beginning of the study and again 3 months after acaricide treatment. Significant reductions in carpet Der p 1 levels were achieved in group A (22.83 v. 13.26 micrograms Der p 1/g dust; P = 0.04) and group B (21.76 v. 13.26 micrograms Der p 1/g dust; P = 0.01), but mite levels were not reduced in any of the mattresses treated. There was also no improvement in airway hyperreactivity in any of the groups. This study clearly demonstrates that at present it is not possible to reduce Der p 1 antigen levels in mattresses in the Cape Peninsula with the available acaricides, even when one of these is combined with a detergent solution. Until strategies are developed which will significantly reduce Der p 1 levels in the bedding of sensitive individuals, a reduction in ongoing airway inflammation and airway hyperreactivity cannot be expected. The efficacy of an air-cleaning device equipped with a high efficiency particulate air (HEPA) filter (without further avoidance measures) was studied in patients allergic to house dust mite. The effects of the air-cleaner on indoor Dermatophagoides sp. levels, symptom score and bronchial hyperresponsiveness in nine mite-allergic patients were assessed using a cross-over controlled study. No significant effect was demonstrated on indoor Dermatophagoides sp. levels when comparing the period of air-cleaner activity (2 months) with the control period (2 months). The Dermatophagoides sp. levels in the houses studied were lower than the risk level for asthmatic attacks, making it difficult to assess any effect on asthma; however, neither bronchial hyperresponsiveness nor rhinitis symptom score were changed by air-cleaner activity. During the trial period, however the mean level of Dermatophagoides sp. allergen in the houses changed spontaneously from 4.4 micrograms/g (mean level in the first 2 trial months) to 1.75 micrograms/g of dust (second 2 months) (P less than 0.05). Owing to this change, the mean rhinitis symptom score also decreased (P less than 0.05), even if no significant correlation was demonstrated (r = 0.4 P = 0.089). HEPA filter air-cleaners appear insufficient as substitutes for standard avoidance measures in mite allergic patients. Manufacturers of ionisers claim many benefits from the use of their devices, including the relief of asthma. Particles removed from the air are likely to include airborne allergens, so ionisers may achieve an effect by reducing the allergen load.
                The effect of ionisers on airborne concentrations of house dust mite allergen Der p I was investigated in a double blind, crossover, placebo controlled trial in the homes of 20 children with allergic asthma. Subjects recorded their peak expiratory flow rate (PEFR) twice daily and completed a daily symptom score and treatment schedule on a diary card for two six week periods, one with an active ioniser and the other with a placed ioniser (randomly allocated) used in the living room and the bedroom.
                Airborne Der p I concentrations fell significantly during the active period compared with the placebo period, but there was no significant change in PEFR, symptom scores, or treatment usage. There was an increase in night time cough which almost reached significance during the active period.
                This study indicates that the use of ionisers cannot be recommended in the homes of asthmatic subjects to improve their symptoms. The significant reduction of airborne allergen concentrations may be of use as part of a multidevice allergen avoidance regimen, but the increase in night time cough requires further study. House dust mite (HDM) allergens can accumulate to very high levels in homes. From the observed sensitivity of HDMs to heat and their allergens to steam, a novel treatment of furnishings has been developed.
                We sought to determine whether combined steam and heat treatment of home furnishings reduced asthmatic patients' bronchial hyperreactivity (BHR) and lowered HDM antigen loads.
                The homes of 30 asthmatic subjects aged 18 to 45 years were randomly allocated into 3 groups. In groups 1 and 2 mattresses and duvets were treated with hot air (110 degrees C), followed by steam and then heat again. All their carpets were steam cleaned. Group 2 also had a special ventilation system installed above each patient's bedroom. The homes of subjects in group 3 were sham treated. Neither patient nor laboratory staff was aware of the types of treatment. Der p 1 and 2 levels in the household dust from the lounge, bedroom carpet, and beds were determined before and after treatment and then at 6 and 12 months. BHR, measured by using histamine PD(20) values, was recorded during the 4-week run-in period and at 3, 6, 9, 12 months after treatment.
                Active heat-steam treatment of homes caused a sustained reduction of Der p 1 (P =.003) and Der p 2 (P =.001) compared with no change in sham-treated group 3 homes. Patients whose homes were treated showed a 4-fold reduction in BHR at 9 months in group 1 and throughout the posttreatment period in group 2. No change was observed in the asthmatic subjects whose homes were not treated. These improvements were sustained for 12 months in the homes with bedroom ventilation units.
                A single treatment of home furnishings reduced mite allergen load to below the risk level for sensitization and improved the asthmatic patients' BHR by 4-fold. Recommendations for allergen avoidance or allergen reduction measures play an important part in the treatment of allergic asthmatic patients. The purpose of this study was to test recently developed air-cleaners with respect to their capacity to capture airborne allergen particles and to improve clinical parameters of asthmatic patients sensitized to aeroallergens. Forty five allergic asthmatic patients were studied in a double-blind procedure for 6 months. The patients were divided into three groups of 15 patients. In Group 1, the intervention consisted of the application of active air-cleaners in living-rooms and bedrooms. In Group 2, placebo air-cleaners were used in combination with allergen-impermeable mattress covers. In Group 3, the same intervention was performed as in Group 2 but with active air-cleaners. Allergen levels in mattress and floor dust were measured before, and 3 and 6 months after the interventions. After 6 months, the air-cleaners were dismantled and the filters were analysed for the amount of dust collected and allergen content. Immunological and lung function parameters were measured before, and 3 and 6 months after the interventions. Considerable amounts of airborne dust and allergenic particles were captured in the filters of the air-cleaners. Up to the 18.9 g of dust, 4,513 ng of house dust mite allergen, Der p 1, and 50,000 mU of cat allergen, Fel d 1, (in houses with cats) were collected by air-cleaners in living-rooms. Only in Group 3 (in which both active air-cleaners and mattress covers were used) was a small (less than 1 doubling dose) but statistically significant improvement of provocative concentration of histamine causing a 20% fall in forced expiratory volume in one second (PC20) observed (from 5.96 to 9.02 mg x mL(-1)). The amount of dust and house dust mite allergen collected in the filters was significantly correlated with an improvement of peak flow variation. In combination with other allergen avoidance measures, the examined air-cleaners can contribute to diminished allergen exposure and improvement of airway hyperresponsiveness in asthmatic patients. A double blind controlled trial of Bencard HDM (Migen) for the prophylaxis of asthma in a group of Zambian asthmatics failed to show any benefit. The trial results suggest that asthmatics can benefit from regular supervision and the position of prophylactic and therapeutic medication. The major triggers for allergic asthma are exposure to allergens of the house dust mite, Dermatophagoides pteronyssinus, and of pets. Unfortunately studies of techniques designed to reduce house dust mite and pet allergens have had mixed results. However, new so-called 'improved' products continue to appear on the market and require subjective evaluation. The homes of 60 house dust mite-allergic patients were studied to compare the effects of high-efficiency and standard vacuum-cleaners on allergen concentration. Der p 1 (house dust mite), Fel d 1 (cat) and Can f 1 (dog) allergens were measured in four separate locations in each home. Clinical analysis was by lung function, bronchodilator usage and histamine challenge techniques. There was a significant reduction in Fel d 1 (ng/m2) in dust samples from the living-room carpet (p = 0.046), bedroom carpet (p = 0.003) and mattress (p = 0.013) and living-room sofa (p = 0.005) after 12 months of using the high-efficiency cleaners, but only in the mattress sample using the standard cleaners (p = 0.014). Can f 1 (ng/g dust) was reduced in the mattress sample after using the high-efficiency vacuum-cleaners (p = 0.028), but not at other sites. Der p 1 levels were not significantly changed over this period. Clinically, patients in the high-efficiency group showed improvements in peak expiratory flow rate (PEFR) (p = 0.004), FEV1 (p = 0.026) and bronchodilator usage (p = 0.005) after 12 months. When the cat-sensitive patients were analyzed separately, improvements in histamine PC20 (p = 0.039) were also seen. Reducing Fel d 1 concentrations, in the absence of any change in Der p 1 concentrations, can produce significant improvements in the lung function of atopic, asthmatic patients. This effect was primarily achieved in those patients with cat sensitivity, but who did not possess a cat themselves. Thirty-one adult patients with asthma caused by house-dust mites (HDM) were included in this placebo-controlled, double-blind study to evaluate the efficacy and safety of specific immunotherapy (SIT) with biologically standardized extracts of HDM. The specific diagnosis was confirmed by skin prick tests, specific IgE, and bronchial provocation tests with HDM allergens. The patients were randomized to receive active treatment with extracts of either Dermatophagoides pteronyssinus (Dpt) or D. farinae (Dfa) (Alutard SQ, ALK, Denmark) or placebo injections. Twenty-three patients completed the study. After 1 year of treatment, we found a clinically important and significant reduction in both asthma medicine consumption (inhaled steroids 38% and beta 2-agonists 46%) and symptom score (57%) in the actively treated group, but not the placebo group. These findings were confirmed by a significant decrease in skin and bronchial sensitivity to HDM in the active group. Additionally, there was a significant difference in the patients' scores for effect in favor of the actively treated group. Total IgE and specific IgE to HDM showed no significant changes before and after treatment for either group. Spirometric lung-function measurements showed a significant increase in forced expiratory volume in 1 s (FEV1) from 85% before to 89% of predicted values after treatment for the actively treated group. Peak-flow measurements at home showed no significant changes during the study. It is concluded that allergen SIT is an effective treatment in adult patients suffering from asthma due to HDM. A double blind, randomized, comparative study versus placebo, was done during 6 months in 32 children, aged 4-12 years, who suffer from either allergic asthma or rhinitis or both, slept in a bedroom rich in dust mite, have well documented allergy solely to house dust mite (H.D.M.), and a condition severe enough to require continuous medication. After thorough cleaning, their bedrooms were sprayed on day 0 and day 90 with the total content of a canister containing either Acardust or Placebo. Rooms were cleaned regularly throughout the study period. Each child completed an individual daily score card (scales from 0-3) for asthma, and rhinitis symptoms, medication taken, and any additional symptoms. Peak flow was recorded twice weekly. All the children were examined every month (at the clinic) when also PFF, FEVI, doctor's and patient's opinion of clinical symptoms were recorded according to the same scale (0-3) and dust samples from child's bedroom were examined for H.D.M. antigen content. At day 0, 90 and 180, total IgE and dust mite specific IgE determination was done. At the end of the study, patient's and doctor's opinion about the spray's efficacy were recorded on a scale from 0-3. The results were in favor of Acardust for asthma, according to patient's opinion (p = 0.001), doctor's opinion (p = 0.04) and individual score cards (p = 0.03), and for nasal secretion (p = 0.01), sneezing and lacrimation (p = 0.02); concurrent medication dropped significantly (p = 0.01) in the Acardust group. No side-effects were reported. We consider Acardust a safe and valuable preventive treatment in H.D.M. allergy. Exposure to allergens plays a role in the development of bronchial hyperresponsiveness and in the chronic inflammatory response seen in asthmatic patients. House dust mites (HDMs) are an important source of allergen. Reduction of these allergens might lead to better lung function and reduction of asthma symptoms.
                The effect of HDM-impermeable covers on HDM allergen levels, peak flow values, and asthma symptoms were measured. Therefore a randomized clinical trial was carried out.
                Fifty-two allergic asthmatic patients were randomly allocated to use the HDM-impermeable or placebo covers. During the study period, daily peak flow and asthma symptom scores were recorded. Dust samples were taken from the mattresses.
                We observed a significant reduction in HDM allergen levels on the mattresses after encasing them with HDM-impermeable covers (reduction of 87% of Der p 1 in micrograms per gram of dust; P <.001). Baseline symptoms were so low that no improvement could be established. Morning peak expiratory flow is significantly higher in the intervention group compared with that seen in the placebo group during the study period (beta=20.2; P <.01).
                HDM-impermeable covers significantly decreased the level of HDM allergens. Furthermore, morning peak flow was significantly increased during the intervention period. This study indicates that HDM allergen-avoidance measures might have beneficial effects on allergen reduction and asthma outcome. The safety and the efficacy of sublingual-swallow immunotherapy (SLIT) in perennial conjunctivitis caused by house dust mite were evaluated in a double-blind, placebo-controlled study including 60 patients for 24 months.
                Patients received either placebo or SLIT with standardized Dermatophagoides pteronyssinus (D.pt.) and D. farinae (D.f.) 50/50 extract. The evaluation of the efficacy of the SLIT was obtained by using standardized D. pteronyssinus (D.pt.) extracts on the antigen-specific conjunctival provocation test (CPT). Specific CPT, skin sensitivity and serum-specific IgE were performed before starting treatment and 6, 12, 18 and 24 months.
                Of the 60 patients included, only 45 completed the study (26 in the active group and 19 in the placebo group, P < 0.05). Two out of 30 (6.6%) patients dropped out because of insufficient efficacy in the active group compared to eight out of 30 (26.6%) in the placebo group (P < 0.05). There was a significant increase in the antigen threshold required to obtain a positive CPT from 8.2 IR [95% confidence interval (CI) 5.9-11.4] at baseline to 21.7 IR (95% CI 15.4-30.4) at 2 years (M24) in the active group, compared to 8.1 IR (95% CI 5.4-12.1) at baseline to 8.1 IR (95% CI 5.1-12.4) at M24 in the placebo group (P < 0.04 for overall treatment difference, P < 10-7 for the time-treatment interaction; repeated measures ANOVA). Differences between groups at individual time points were significant from 18 months on. Despite increased antigen concentrations, CPT scores were lower overall in the active than in the placebo group (P < 0.001). No serious adverse effects were reported.
                SLIT effectively increased the antigenic threshold required to obtain a positive CPT to house-dust mite antigen. Tolerance to and innocuity of SLIT were comparable to previous studies. This could justify recommending SLIT for the preventive treatment of perennial conjunctivitis caused by house dust mites. Anti-allergic mattress encasing may provide clinical benefit in asthmatic patients. However, the effect of mattress encasings on allergen-specific parameters, such as bronchial reactions to house dust mite (HDM) challenge, is not clear.
                To investigate the effect of anti-allergic mattress encasings on allergen sensitivity in patients with moderate to severe asthma.
                Twenty-seven patients with asthma and HDM allergy were studied in a double-blind, placebo-controlled study. Concentrations of Dermatophagoides pteronyssinus (Der p 1) were measured in mattress dust before and after 1 year of treatment; bronchial histamine challenge, bronchial challenge with HDM and intradermal skin challenges with HDM were performed. The number of eosinophils in peripheral blood was assessed.
                In the active group, but not in the placebo group, there was a significant reduction in Der p 1 concentration in the dust collected from the mattresses after 1 year of treatment compared to before. There was a significant difference between the groups with respect to HDM-induced early-reaction (ER) in the airways and the number of blood eosinophils, which reflected an increase in ER and eosinophils in the placebo group without significant change in the active group. No significant improvement in PC20 histamine, late-reaction (LR) and skin tests was found in either groups.
                Our data suggest that encasings protect against a further increase in allergen sensitivity in asthmatic patients, so their use should be recommended. The efficacy of the acaricide benzyl benzoate as an additive to a chemically and technically defined cleaning substance (Acarosan) was tested in a multicentric, prospective, randomized, controlled study on 118 outpatients with bronchial asthma due to house-dust-mite allergy. Subjective reports from patients and doctors revealed an improvement in clinical complaints in more than 50%, with only small differences between the verum and the placebo group. Objective parameters such as titrated skin tests, RAST, and bronchial challenge tests with histamine and Dermatophagoides pteronyssinus (D. pt.) did not reveal any significant changes either during the year of testing or between the two groups. A clinical improvement as observed in either group could not be assessed by objective parameters. Additional questions as to the merits of the possible prophylactic use of benzyl benzoate over more than 1 year remain unanswered. The effectiveness of avoidance of house-dust-mite allergen (Dermatophagoides pteronyssinus 1 [Der p1]) in the management of asthma is uncertain.
                We conducted a double-blind, randomized, placebo-controlled study of allergen-impermeable bed covers involving 1122 adults with asthma. The primary outcomes were the mean morning peak expiratory flow rate over a four-week period during the run-in phase and at six months and the proportion of patients who discontinued inhaled corticosteroid therapy as part of a phased-reduction program during months 7 through 12. Der p1 was measured in mattress dust in a 10 percent random subsample of homes at entry and at 6 and 12 months.
                The prevalence of sensitivity to dust-mite allergen was 65.4 percent in the group supplied with allergen-impermeable bed covers (active-intervention group) and 65.1 percent in the control group supplied with non-impermeable bed covers. The concentration of Der p1 in mattress dust was significantly lower in the active-intervention group at 6 months (geometric mean, 0.58 microg per gram vs. 1.71 microg per gram in the control group; P=0.01) but not at 12 months (1.05 microg per gram vs. 1.64 microg per gram; P=0.74). The mean morning peak expiratory flow rate improved significantly in both groups (from 410.7 to 419.1 liters per minute in the active-intervention group, P<0.001 for the change; and from 417.8 to 427.4 liters per minute in the control group, P<0.001 for the change). After adjustment for base-line differences (by analysis of covariance), there was no significant difference between the groups in the peak expiratory flow rate at six months (difference in means, active-intervention group vs. control group, -1.6 liters per minute [95 percent confidence interval, -5.9 to 2.7] among all patients [P=0.46] and -1.5 liters per minute [95 percent confidence interval, -6.9 to 3.9] among mite-sensitive patients [P=0.59]). There was no significant difference between the groups in the proportion in whom complete cessation of inhaled corticosteroid therapy was achieved (17.4 percent in the active-intervention group and 17.1 percent in the control group) or in the mean reduction in steroid dose, either among all patients or among mite-sensitive patients.
                Allergen-impermeable covers, as a single intervention for the avoidance of exposure to dust-mite allergen, seem clinically ineffective in adults with asthma.
                Copyright 2003 Massachusetts Medical Society nan The aim of this double-blind, randomized study was to investigate the effectiveness of an acaricidal cleaning product in modifying both clinical symptoms and mite allergen levels over a period of at least 1 year.
                Twenty-six asthmatic patients with proven Dermatophagoides pteronyssinus (Dp) asthma were selected; three were withdrawn from the trial. The patients' homes were divided into two groups; 11 homes were treated with solidified benzyl benzoate and tenside agents (A), and 12 were treated with a placebo (P). Two applications were performed at the beginning of the trial and at least 6 months later. Patients were examined 1 month before the trial, at the beginning of the trial, and every 3 months over a period of 1 year. Indoor mite exposure was evaluated by three methods: semiquantitative guanine determinations, quantitative guanine determinations, and the measurement of Der p I + Der f 1 (antigen P, of Dp + antigen F1 of D. farinae) levels.
                The symptom scores established at the beginning of the trial and 12 months later showed a statistically significant improvement only in the A group (p < 0.01). The visual analog scale also showed a statistically significant difference both in the A (p < 0.05) and P groups (p < 0.01). No statistical differences were found between medication scores in the A or P groups. A statistically significant increase was also observed for forced expiratory volume in 1 second and maximal expiratory flow rate 25/75 in the two groups (p < 0.05 for P group; p < 0.01 for A group). The mean decreases in Der p I + Der f 1 in patient mattresses between the beginning of the trial and after 12 months were 20% for the acaricide group and 17% for the placebo group, respectively (NS). For house dust samples with origins other than the patients' mattresses we found significant decreases in Der p I+Der f 1 in the A group (p < 0.01 for carpets and p < 0.05 for upholstery elements). Immunotherapy has been shown to reduce allergen sensitivity to allergens such as cat and dust mite. The aim of this study was to investigate the effect of cat or dust mite immunotherapy on bronchial hyperreactivity and the need for inhaled corticosteroids in children with asthma, cat or dust mite allergy, and hay fever.
                Twenty-nine children, 7 to 16 years old, completed the 3-year study. They were randomly allocated to receive cat/dust mite or placebo and birch/timothy immunotherapy.
                Before immunotherapy was begun and then once each year, bronchial histamine challenges were performed. Bronchial allergen challenge with the perennial allergen was done before and after the 3-year study. Pharmacotherapy was given according to a standardized protocol.
                PC20 allergen increased significantly in both the active immunotherapy group (P <.001) and in the placebo-pollen group (P <.05). PC20 histamine increased continuously in the active immunotherapy group (P <.05 and P =.002 after 1 and 3 years, respectively) and had also increased after 3 years in the placebo-pollen group (P <.05). The difference between the 2 groups was significant for PC20 allergen (P =.001) but not for PC20 histamine. There was no significant change in the dose of inhaled budesonide needed for symptom control in either of the groups.
                Pollen immunotherapy combined with inhaled corticosteroids results in improvement of both cat/dust mite bronchial sensitivity and hyperresponsiveness to histamine. The combination of cat or dust mite, pollen immunotherapy, and inhaled budesonide enhances this improvement. Cat immunotherapy also induces cat allergen tolerance. The warm, humid environment in modern homes favours the dust mite population, but the effect of improved home ventilation on asthma control has not been established. We tested the hypothesis that a domestic mechanical heat recovery ventilation system (MHRV), in addition to allergen avoidance measures, can improve asthma control by attenuating re-colonization rates.
                We conducted a randomized double-blind placebo-controlled parallel group trial of the installation of MHRV activated in half the homes of 120 adults with asthma, allergic to Dermatophagoides pteronyssinus. All homes had carpets steam cleaned and new bedding and mattress covers at baseline. The primary outcome was morning peak expiratory flow (PEF) at 12 months.
                At 12 months, the primary end-point; change in mean morning PEF as compared with baseline, did not differ between the MHRV group and the control group (mean difference 13.5 l/min, 95% CI: -2.6 to 29.8, P = 0.10). However, a secondary end-point; evening mean PEF, was significantly improved in the MHRV group (mean difference 24.5 l/min, 95% CI: 8.9-40.1, P = 0.002). Indoor relative humidity was reduced in MHRV homes, but there was no difference between the groups in Der p 1 levels, compared with baseline.
                The addition of MHRV to house dust mite eradication strategies did not achieve a reduction in mite allergen levels, but did improve evening PEF. Home mattresses of 24 asthmatic children with house dust mite allergy were sprayed with either benzyl-benzoate foam or placebo in a double blind fashion, 10 days before the children left the residential house for asthmatic children Istituto Pio XII (located in the Italian Alps in an environment free of mites) and went back to their own home for the Christmas and Easter holidays. A further group of 8 children, whose mattresses received no treatment, was kept as an absolute control. Two days after spraying, benzyl-benzoate or placebo were vacuumed from the mattresses. Acarex test was performed immediately before spraying and at the end of each holiday period of 20 and 10 days, respectively. Bronchial hyperreactivity as well as serum and nasal secretory specific IgE for Dermatophagoides pteronyssinus were assessed in all children immediately before leaving and within 48 hr after returning to the residential house. The results of the study show that sprayed benzyl-benzoate foam was no more effective than placebo in reducing the level of house dust mite recovered from patients' mattresses, or in reducing bronchial hyperreactivity and IgE concentration in serum and nasal secretions. Allergen avoidance is regarded as an important approach to management of atopic asthma. The effect of Intervent bed covering systems on house dust mite (HDM) allergen exposure, asthma symptoms and markers of inflammation was investigated in 31 HDM sensitive asthmatic children. Dust concentrations of Dermatophagoides pteronyssinus allergen 1 (Der p 1) were monitored before and after covering the mattress, duvet and pillow with active and placebo covers for 3 months, in a single-blind, cross-over trial. Twice daily peak expiratory flow rate (PEFR), daily symptom scores and treatment schedule were recorded. Bronchial hyperresponsiveness was monitored by histamine challenge (provocative concentration of histamine causing a 20% fall in forced expiratory volume in one second (PC20)), and inflammation by measuring eosinophil cationic protein (ECP), eosinophil protein X (EPX), eosinophil peroxidase (EPO), and soluble interleukin-2 receptor (sIL-2R) in serum. There was a significant reduction in Der p 1 when the mattress, duvet and pillow were covered with the active bedding. There was no significant improvement in symptoms of asthma, PEFR, bronchodilator usage of PC20. Also, ECP, EPX, sIL-2R concentrations did not change for either treatment. EPO concentrations were significantly lower in the active compared to the placebo period. The active bed covers reduced retrievable Dermatophagoides pteronyssinus allergen 1 (Der p 1) from the bedding, with short term clinical benefit. A cross-over controlled trial has been conducted among 32 adult patients with mite-sensitive asthma. The bedclothes and pillows of each subject were laundered and vacuum-cleaned and a plastic cover applied to the mattress for six weeks in an attempt to reduce exposure to mites. No improvement in daily peak-flow reading or drug usage was found in comparison with a control period.
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.