Hand-colored scanning electron micrograph of an aggressive House Dust Mite (D. farinae) by Martin Oeggerli. This animal has been captured in the ‘pumped’ (aggressive behavior) posture.
The house dust mite is a cosmopolitan pyroglyphid mite that lives in human habitation. Dust mites typically measure between 0.2–0.3 millimetres (0.008–0.012 in) in length and feed on organic detritus, such as flakes of shed human skin, and flourish in the stable environment of dwellings.
House dust mites are a common cause of asthma and allergic symptoms worldwide. The mite’s gut contains potent digestive enzymes (notably proteases) that persist in their feces and are major inducers of allergic reactions such as wheezing. The mite’s exoskeleton can also contribute to allergic reactions.
There are two different species which occur widely: the European house dust mite (Dermatophagoides pteronyssinus) and the American house dust mite (Dermatophagoides farinae); a third species (Euroglyphus maynei) also occurs worldwide.
Unlike scabies mites or skin follicle mites, house dust mites do not burrow under the skin and are not parasitic.