It is the common name given to animals belonging to the subclass Acari of the Arachnida class. The word acari derives from the Greek akares, "little". Most adults are between 0.25 and 0.7 mm long, although some species are even smaller.

They live about two months, mating one to two times, laying about 20 to 50 eggs. The most favorable time for mating is between spring and autumn.

In our homes, dust mites feed on skin peeling particles from humans and animals. Every day, a human sheds about 1 g of these pieces of skin. Mites abound in mattresses, wool blankets, feather pillows, carpets, sofas and plush dolls, developing in ideal above average humidity conditions around 70% to 80%, and temperature above 20°C. At altitudes above 1200 meters, the environment is not suitable for mites. For this reason, a stay in mountainous regions can alleviate certain allergies.

Droppings of dust mites and dead mites disperse into fine dust being inhaled and possibly causing allergies. In Brazil, mites are the main responsible for respiratory allergy conditions, such as allergic rhinitis and asthma.