Get Rid of Unwanted House Guests -- Dust Mites

Moist, balmy air, good weather and spring break may attract more than relatives to your home. Dust mites, microscopic creatures related to spiders, thrive on moisture. When moisture gets trapped inside a home, dust mites settle in and reproduce rapidly.

"Dust mites live off of human skin scales," says Harold S. Nelson, MD, an allergist at National Jewish. "People slough off dead skin cells all the time, and, in the process, dust mites infiltrate the soft surfaces of bedding, pillows, sofas and carpets."

Almost everyone is exposed to dust mites, but not everyone is sensitive to them. "In one study, children allergic to dust mites were five times more likely to have asthma than children who were not allergic to the microscopic bugs," he notes.

Since humidity is the environmental sanctuary for dust mites, the first step is to measure your home’s moisture level. "The easiest, least expensive way," Dr. Nelson says, "is to buy a $15 hygrometer to assess indoor humidity. Optimally, humidity in your home should be below 40 percent." Humidity content between 40 and 50 percent is marginal in terms of dust mite control. In the 50 to 60 percent range, dust mite proliferation can be bothersome, and over 60 percent is very bad.

Air conditioning is the most effective way to control indoor moisture, because it reduces moisture in the air. "If you have an inside air conditioner," he says, "make sure you have good drainage, so there is no standing water inside the cooler."

Pillows and mattresses are prime habitats for dust mites, and the bed is the main source of human exposure. Dr. Nelson recommends using "special allergen-impermeable casings for mattresses and pillows to keep allergens from reaching you."

The casings are available as tightly woven fabrics and can be purchased at stores carrying allergy-related items.

Terrazzo and tile flooring also limit dust mite exposure. These floorings don’t provide the soft nesting areas that carpets do.