Understanding dust mite covers

What are dust mites?

House dust mites are microscopic insect-like organisms that live in all homes in which there is adequate humidity for at least part of the year.  Technically, they are not insects but are arachnids, related to spiders and ticks, and under the micrsocope look very much like tiny ticks.  They are not bedbugs, and they do not bite.  However, their fecal waste particles contain substances which are highly allergenic, and people with an allergic tendency often develop symptoms as a result of that exposure. 

What are the symptoms of dust mite allergy?

Symptoms may affect the nose (allergic rhinitis), eyes (allergic conjunctivitis),  skin (atopic dermatitis; eczema), and/or lower respiratory tract (allergic asthma).  Symptoms may be seasonal or year-round, depending on the patient's level of sensitivity and the dust mite growth pattern in a given location.  Symptoms may be mild, moderate or severe.

Where in the home do dust mites live?

Dust mites live in dark and humid environments near people and pets, whose shed skin scales are their main food source.  Dust mite numbers, and mite allergen levels, are highest in pillows, mattresses, upholstered furniture, carpeting, stuffed toys, and clothing.  They do not live on hard wipeable surfaces where they are unable to penetrate the surface and get away form the light.  For most people, the pillow, mattress and blankets are the biggest source of dust mite allergen exposure.

What can be done to decrease exposure to dust mite allergen?

Full dust mite avoidance measures are described in the video below.  However for our pruposes here, we emphasize the most important measures of surrounding the pillow and mattress with allergen-impermeable covers.  These trap the dust mites and their allergens within the pillow and mattress so that they do not come in contact with the sleeper.

How can I recognize a good quality dust mite cover?

The best covers encase the entire matress (top, sides and bottom) and are made from tightly woven microfiber fabrics that prevent the passage of mite allergen, yet allow the passage of air, heat and water vapor for comfort.  The mite allergen particles are much smaller than the dust mites themselves, so the key is  to block not only the mites but more importantly their allergen.  This means that the fabric must have very small pores, too small for the allergen-containing particles cannot pass.  It is hard for the consumer to know which covers are effective and which are not.  A medical professional can examine them under the microscope.  Larger areas of light showing through the fabric indicate larger pores, through which allergen can pass.