House dust is a mixture of many substances. Its content may vary from home to home, but the most common allergy triggers are: Dust mites, Cockroaches, Fungi (Mold), Animals.
Did you know that you could be sharing your bed with anywhere from 100,000 to 10 million dust mites? These microscopic organisms, which are related to spiders, live in many homes. Too small to see with the naked eye, dust mites thrive in warm, humid environments — eating dead skin cells and nesting in dust-collecting bedding, fabric, carpet and furnishings.
The residue that dust mites leave behind in the form of their feces and decaying bodies mixes with dust and becomes airborne. If you aren't allergic to dust mite residue, it's not harmful. But if you are, inhaling the residue can cause bothersome allergy symptoms, including wheezing, sneezing, watery eyes and runny nose.