Dust mites are microscopic, insect-like pests that generate some of the most common indoor substances—or allergens—that can trigger allergic reactions and asthma in many people. Hundreds of thousands of dust mites can live in the bedding, mattresses, upholstered furniture, carpets or curtains of your home. They feed on the dead human skin cells found in dust. Dust mites are not parasites; they don't bite, sting or burrow into our bodies.