You've seen their ugly photographs on TV and in newspapers and magazines. They loom several inches tall, with eight crooked bony legs, a giant hard-shelled body, short antennas and beady eyes. They infest your carpets, linens, curtains, bedding and furniture. And when it's cold, they hibernate in your mattress. They can make life miserable with sneezing, wheezing and inflammation.
These mites are actually smaller than the period at the end of this sentence. But, considering their significant health effects on many allergic people, you realize they live up to their huge appearance under a microscope.
What is the dust mite?
The house dust mite is a ubiquitous animal belonging to the arthropods, a group that includes such other annoying and noxious animals as ticks, spiders, mosquitoes, flies and fleas. The scientific name, Dermatophagoides species, suggests the lifestyle of the house dust mite: It eats flakes of dead skin and dander that fall from the bodies of humans and other animals. Although you can't see their microscopic mites, they are present in varying numbers in all homes. They thrive in moist climates and are less plentiful in extremely dry climates.
It is not the mite itself that causes trouble for people, but its shed skin and fecal matter. These substances bring misery to millions of allergy sufferers.
"The mite's microscopic feces and cast skins are potent allergens to many people," says Barb Ogg, an educator with the University of Nebraska Cooperative Extension in Lancaster, Neb. "Allergic reactions are similar to a person having hay fever, runny nose and eyes, and frequent sneezing. Some sensitive individuals may have asthmatic reactions."
Eliminating the mite
Almost half of the homes in America are infested with dust mites, according to a report by the National Institutes of Health, so allergists and immunologists try to make sure their patients have eliminated as much of the dust in their households as possible before determining a treatment action.
"With dust mites, you try to do environmental control first," says David Bernstein, M.D., an allergist with the University of Cincinnati's division of immunology in Cincinnati, Ohio.
Dust mites like warm, humid, dusty places. Some favorite places are bedding, upholstered furniture and carpets. They thrive in summer and die in winter. In a warm, humid house, however, they continue to thrive even in the coldest months.
Try these ways to rid your house of mites:
Encase the box springs, mattresses, and pillows in a zippered, dust-proof or allergen-proof cover.
Wash sheets, blankets and other bedclothes frequently, using water that is at least 130 degrees F. Lower temperatures will not kill mites. If your water heater is set to a lower temperature, which is commonly done to prevent children from scalding themselves, wash items at a coin-operated laundry, which uses high wash temperatures.
When you vacuum, use a vacuum with a HEPA (high-efficiency particulate air) filter or one that filters air through water.
If you can, remove carpet from the bedroom and replace it with hardwood, linoleum or tile. If that's not possible, vacuum the carpet and rugs weekly and ask your health care provider about sprays that can be used on rugs and upholstery to kill the mites.
When dusting, first wipe all furniture with a moist cloth. Don’t forget to vacuum your curtains, as well. Curtains, drapes, and horizontal blinds can be replaced with vertical blinds, which do not collect dust.
In humid climates, use a dehumidifier to keep air dry. This will help prevent dust mites.
Use a high efficiency paper filter for the furnace.
Keep dirty clothes in a hamper by the washer, not in the bedroom or bathroom.
Killing off the mites is the best way to eliminate these allergens. Allergy shots and/or medication, however, can alleviate, and sometimes stop, the symptoms that are bound to occur.
Injections and medication
"The incidence of allergies has increased over the last 20 years. It has more than doubled," says Dr. Bernstein.
But making the diagnosis has remained relatively unchanged for years. Allergists determine whether someone is allergic to the mites by several methods: listening to patients describe the situations in which they react to the "disturbing of mite particles" -- changing bedding, vacuuming, sweeping, dusting or sleeping; by doing a skin test to search for a specific reaction to the dust mite allergen; or by immunologic testing, such as the radioallergosorbent test (RAST).
Dr. Bernstein and other allergists recommend allergy shots for those who have strong reactions to dust mite particles and for those who have difficulty controlling their symptoms with preventive measures and medications.
Whether a patient gets allergy shots is entirely up to the patient, Dr. Bernstein says. Shots are given by a medical professional once or twice a week for six months or longer and then once every two to four weeks thereafter for up to three to five years.
"A lot of people don't want to do that," says Dr. Bernstein. "It's a tradeoff. If they are suffering enough, they'll let you know they want it."