Dust mites are very small, microscopic creatures that primarily live on dead skin cells regularly shed from humans and their animal pets. Dust mites are harmless to most people. They don't carry diseases, but they can cause allergic reactions in asthmatics and others who are allergic to their droppings. Skin cells and scales, commonly called dander, are often concentrated in sofas, mattresses, carpets, beds and pillows which often harbour large numbers of these microscopic mites. Most people are unaware that they share their bed with up to ten million dust mites. These microscopic organisms are related to spiders and are too small to see with the naked eye. They particularly thrive in warm, humid environments.
The adult female Dermatophagoides farinae can lay up to eighty eggs, either one at a time or in small groups of about three to five eggs each. When the larva first comes out of the egg, it has six legs. However, after the first time they molt, they will have eight legs. This is their nymph stage and they actually go through two nymphal stages before reaching adulthood. The time period between the hatching and adulthood is approximately one month and the adult will survive up to another three months. Their life cycle is approximately four months in total.