Dust mites are microscopic animals, too small to be seen with the naked eye, that feed on human skin scales. They persist in bedding, carpets, stuffed furniture, old clothing and stuffed toys. Dust mites are most common in humid climates, and they don't survive when the humidity is below 50 percent.
If droppings of dust mites are inhaled or come in contact with the skin, they may cause allergic symptoms and aggravate asthma and/or eczema. Examples of allergy symptoms include itchy eyes, runny nose and rash.