Dust mites rule the house

Researchers in Denmark, publishing in the new issue of theCochrane Review, say there’s little we can do to combat dust in our homes—and the dust mites that come with it. No amount of cleaning, whether its frequently washing bedding at high temperatures, beating cushions outside or throwing away toys and other furniture, will bring them under control. Nor will costly equipment, such as special mattress covers or vacuum cleaners. Although this may sound like music to the ears of most of us—any excuse to avoid extra housework!—it is not good new for asthma sufferers.

Dust mites are spider-like creatures, invisible to the human eye, that eat the skin we shed and live in our bedding, carpets, stuffed toys, furniture and curtains. They’re generally harmless but, according to theAsthma Society of Canada, their body parts and droppings contain a substance that can trigger asthma attacks in people who are allergic. Specialists have been coming up with different physical and chemical interventions to eliminate them for years, in hopes of easing the suffering of people with asthma.

However, thisnew report—a review of 54 previous studies involving 3,000 asthma patients—finds that none of these interventions effectively reduce exposure to dust mites. “If you are wondering why it is that mattress covers and the other strategies are not effective, the likely answer is that all these treatments do not have a large enough effect on the occurrence of allergens from house dust mites,” said Dr. Peter Gotzsche, director of theNordic Cochrane Centrein Copenhagen, in a press release. “The level of allergens is so high in most homes that what remains after the treatment is still high enough to cause asthma attacks.”

Studies, which ranged from about two weeks to two years duration, employed a variety of interventions. Some studies used chemicals to kill mites, while others used physical interventions such as encasing mattresses and pillows in covers that mites cannot get through. Other studies called for frequent laundering of bed linens in hot water or bleach; beating cushions outside; and removing toys, plants and furniture from a home.

Gotzche also called for “reviews and guidelines to reflect the facts.”Recommendationsby the National Asthma Education and Prevention program in the U.S. and the Asthma Society Canada, among others, list “effective strategies for minimizing dust mites,” that this new work now suggests are unfounded.