Experts Take Bite Out Of Allergy Control Method

BOSTON -- Some people go to great expense to try and control allergies and asthma. But one of the most popular and well-marketed methods may fall short on its claim.

Amy Gunville has encased her mattress, box spring and pillows in special covers to prevent inhaling what dust mites leave behind.

"Dust mites are a big, huge allergy trigger for me," Gunville said.

The microscopic mites flourish in beds, feeding on human skin scales. People shed enough each night to feed over 1 million mites a day. And if you're allergic to mites, you suffer.

Impermeable bed covers are supposed to significantly lower your exposure to dust mites. In fact, most doctors recommend that you buy them. But two new studies have found them ineffective at improving the symptoms of allergies and asthma.

"I don't think we should be discouraged by these findings," said Dr. Diane Gold, of Brigham and Women's Hospital in Boston.

That's because the studies in this week's New England Journal of Medicine studied impermeable covers alone -- not as part of a comprehensive mite control approach.

"If you do it just by itself, it probably won't work. But I tend to believe that the bedding covers are the most critical first step," said Bill McTighe, of Home Environmental in Lexington, Mass.

Home Environmental also recommends what most experts do for serious mite allergies -- replacing carpet with wood floors, dusting and vacuuming weekly, controlling bedroom humidity levels and washing bedding every week in hot water.

"I took all those precautions, and I still wake up sneezing," Gunville said.

But the new studies point out that not all adult allergies and asthma cases respond the same.

Don't throw out the encasements if you've invested in them, but don't count on them working if you don't do the other interventions that your physician has recommended, experts say.

It's important to note the studies did not include children, and experts caution against eliminating their impermeable covers. They also suggest that adults follow their doctors' advice.