English: House dust mites are tiny – around 0.25mm to 0.50mm long. They feed on organic 'dust' such as flakes of shed human skin, and love our houses where they can be found in our beds, clothing, curtains and carpets. The allergens produced by the mites are found in their bodies, secretions, faecal matter and shed skins. Some of their gut enzymes can be strongly allergenic and these often persist in their faecal matter. These mites are ubiquitous. They have even been found in the Antarctic and on the Mir Space Station. Their recorded history goes back to the 17th Century.