title: No Concentration Decrease of House Dust Mite Allergens With Rising Altitude in Alpine Regions.
abstract: OBJECTIVE
  Several studies over the past 4 decades have indicated a significant reduction in house dust mite (HDM) and HDM allergen concentration in areas higher than 1,500 m above sea level. These have served as basis of allergen avoidance therapies for HDM allergy and asthma. However, modern construction techniques used in the insulation, heating, and glazing of buildings as well as global warming have changed the environmental parameters for HDM living conditions. The present study revisits the paradigm of decreasing HDM allergen concentrations with increasing altitude in the alpine region of Germany and Austria.
  
  
  METHODS
  A total of 122 dust samples from different abodes (hotels, privates and mountain huts) at different altitudes (400-2,600 m) were taken, and concentrations of HDM allergens were analyzed. Humidity and temperature conditions, and numerous indoor environmental parameters such as fine dust, type of flooring, age of building, and frequency of cleaning were determined.
  
  
  RESULTS
  HDM allergen concentrations did not significantly change with increasing altitude or relative humidity. At the level of indoor parameters, correlations could be found for different flooring types and the concentration of HDM allergens.
  
  
  CONCLUSIONS
  In contrast to the widespread view of the relationship between altitude and HDM allergen concentrations, clinically relevant concentrations of HDM allergens could be detected in high-lying alpine regions in Austria and Germany. These results indicate that improvement in conditions of asthmatic patients sensitized against HDMs during a stay at high altitude can no longer be ascribed to decreased levels of HDM allergens, instead, other mechanisms may trigger the beneficial effect.
authors.affiliation: Institute of Ecomedicine, Paracelsus Medical University, Salzburg, Austria.
authors.forename: Carina
authors.initials: C
authors.lastname: Grafetstätter
authors.affiliation: Institute of Ecomedicine, Paracelsus Medical University, Salzburg, Austria.
authors.forename: Johanna
authors.initials: J
authors.lastname: Prossegger
authors.affiliation: Institute of Ecomedicine, Paracelsus Medical University, Salzburg, Austria.
authors.forename: Herbert
authors.initials: H
authors.lastname: Braunschmid
authors.affiliation: Institute of Physiology and Pathophysiology, Paracelsus Medical University, Salzburg, Austria.
authors.forename: Renata
authors.initials: R
authors.lastname: Sanovic
authors.affiliation: Institute of Ecomedicine, Paracelsus Medical University, Salzburg, Austria.
authors.forename: Penelope
authors.initials: P
authors.lastname: Hahne
authors.affiliation: Institute of Ecomedicine, Paracelsus Medical University, Salzburg, Austria.
authors.forename: Christina
authors.initials: C
authors.lastname: Pichler
authors.affiliation: Department of Molecular Biology, University of Salzburg, Salzburg, Austria.
authors.forename: Josef
authors.initials: J
authors.lastname: Thalhamer
authors.affiliation: Institute of Ecomedicine, Paracelsus Medical University, Salzburg, Austria. arnulf.hartl@pmu.ac.at.
authors.forename: Arnulf
authors.initials: A
authors.lastname: Hartl
keywords: Hypersensitivity; allergens; asthma; pyroglyphidae