As they flatten, they provide less support for your head and neck, which may contribute to neck stiffness or poor sleep for some people.” While dust mites do not bite, they leave behind dead bodies and waste products that act as severe indoor allergens. This is the thermal threshold required to effectively kill dust mites. These seal the pillow, creating a physical barrier that prevents sweat from entering and dust mites from taking up residence. Control room humidity: House dust mites struggle to survive when the relative humidity is below 50%.