House dust mites are small and whitish in colour. Between 0.1 and 0.6 mm long, they are barely visible to the naked eye. The mite is related to the spider family. It is completely harmless unless you suffer from allergy to mites.
Minute fragments of mites easily become airborne when house dust is disturbed and are thus inhaled by everyone. When proteins (allergens) from these fragments come into contact with the immune system of an allergic person, an overreaction occurs. Allergy to house dust mite affects millions of people all over the world.
When and where am I exposed to house dust mites?
Mites thrive in dark and humid places at temperatures of around 25° C. Since they feed on human dander (the dead skin cells shed by all humans), mattresses and pillows are an ideal environment for them. They are found in many other places, however, such as clothing, carpets, upholstered seats and soft toys. And we are also regularly in contact with mites outside our homes - e.g. school and kindergartens, public transport, hotels and cinemas.
The general improvement in building insulation to save energy has increased indoor humidity and then improved living conditions for mites.