Dust mites are a type of spider.
They are microscopic, about the size of a sharp pencil dot. Dust mites and their particles are the main causes of symptoms in dust-allergic people in the Puget Sound area. If there were no mites, many people wouldn't have their year-round allergy symptoms. Weekly, launder all bedding and stuffed animals in hot water and dry in a hot cycle. Storing them in the freezer will also kill mites, but will not remove the allergens.