title: House dust mite avoidance measures improve peak flow and symptoms in patients with allergy but without asthma: a possible delay in the manifestation of clinical asthma?
abstract: BACKGROUND
  Asthma caused by allergy to house dust mite is a growing problem. Patients with allergy who do not have asthma (yet) might develop asthma depending on exposure to precipitating factors.
  
  
  OBJECTIVE
  We sought to determine whether house dust mite avoidance measures have an effect on the development of asthma.
  
  
  METHODS
  Patients with allergy (n = 29) who had no diagnosis of asthma (FEV1 of 99.1% +/- 10.6% of predicted, peak flow variability of 5.21% +/- 3.41%, reversibility of FEV1 after 400 microg salbutamol of 3.92% +/- 3.75% according to the reference values) were randomly allocated (subjects blinded) to a treatment (n = 16) and a placebo group (n = 13). House dust mite avoidance treatment consisted of applying Acarosan (Allergopharma, J. Ganzer KG, Hamburg, Germany) (the placebo group used water) to the floors (living room, bedroom), and the use of covers for mattresses and bedding that were impermeable to house dust mite (the placebo group used cotton covers for mattresses only). We tested whether the intervention had an effect on peak flow parameters and asthma symptom scores during 6 weeks of treatment.
  
  
  RESULTS
  Significant improvements were seen in the treatment group in symptom scores (Borg score) for disturbed sleep, breathlessness, wheeze, and overall symptom score. Slight but statistically significant improvements in peak flow (morning, evening, and variability) were seen in the treatment group also. No significant changes were seen in the placebo group.
  
  
  CONCLUSIONS
  Although this study is not long enough to study the development of asthma, the results indicates that house dust mite avoidance measures had an effect on peak flow parameters and asthma symptoms in patients with allergy but without asthma. These findings might implicate that a shift in developing clinically manifest asthma could be achieved with house dust mite avoidance measures. To give a better answer to whether preventing the development of asthma is possible, larger studies with a longer follow-up period are necessary.
authors.affiliation: Department of General Practice and Social Medicine, Medical Centre Dekkerswald, University of Nijmegen, The Netherlands.
authors.forename: S G
authors.initials: SG
authors.lastname: Cloosterman
authors.forename: I D
authors.initials: ID
authors.lastname: Hofland
authors.forename: H G
authors.initials: HG
authors.lastname: Lukassen
authors.forename: M H
authors.initials: MH
authors.lastname: Wieringa
authors.lastname: Folgering HTh
authors.forename: S
authors.initials: S
authors.lastname: van der Heide
authors.forename: B
authors.initials: B
authors.lastname: Brunekreef
authors.forename: C P
authors.initials: CP
authors.lastname: van Schayck
mesh_terms: D000293:Adolescent; D000328:Adult; D000818:Animals; D001249:Asthma / Q000175:diagnosis / Q000517:prevention & control*; D001512:Bedding and Linens; D001565:Benzoates / Q000008:administration & dosage*; D004391:Dust; D004417:Dyspnea / Q000175:diagnosis; D005260:Female; D005430:Floors and Floorcoverings; D006801:Humans; D006969:Hypersensitivity, Immediate / Q000150:complications / Q000175:diagnosis; D008297:Male; D008925:Mites / Q000187:drug effects* / Q000276:immunology; D010366:Peak Expiratory Flow Rate; D012135:Respiratory Sounds / Q000175:diagnosis; D012893:Sleep Wake Disorders / Q000175:diagnosis
chemical_list: D001565:Benzoates; D004391:Dust; C006723:benzyl benzoate