Up to 40 percent of the world population has
allergies, and dust mites are thought to be one of the most common
causes. Doctors often tell patients to buy special mattress and
pillow covers despite a lack of evidence they relieve the problem,
the authors say.
"Based on this analysis which combines data from many different
studies, there doesn't seem to be any benefit to using dust mite
covers to prevent allergic disease or to prevent symptoms," lead
author Whitney Arroyave told Reuters Health.
Arroyave, a researcher with the Tulane University School of Public
Health and Tropical Medicine in New Orleans, and her colleagues
combined results from 24 trials of methods to reduce dust mite
exposure and prevent allergy signs and symptoms
The study team found that use of the mattress covers had a large
effect in reducing exposure to house mite dust levels - about 20
percent - but this reduction had no statistically significant impact
on house dust mite sensitization, or symptoms such as wheezing,
asthma, runny nose or dermatitis.
The results are published in the Annals of Allergy, Asthma and
Arroyave said it isn't clear why dust mite covers don't seem to be
effective in relieving allergies, but it's possible they don't lower
mite levels enough to improve symptoms, or maybe beds aren't the
main source of exposure for the dust mites.
"Or maybe it's not the dust mite at all - maybe they're not causing
the problems," she said.
Arroyave said that dust mite covers cost around $100, which is a
burden, particularly for very low-income people.
"It's expensive to ask them to pay for this," she said.
She added that other researchers have done bigger studies, looking
not just at dust mite covers, but all kinds of dust mite prevention
"They didn't find any results either," Arroyave said, "so I think
we're just saying, you know, look at this again - maybe we need to
revisit the recommendations." Dr. Samuel Friedlander, an allergist
with University Hospitals Rainbow Babies and Children's Hospital and
Case Western Reserve University School of Medicine in Cleveland,
Ohio, said he doesn't plan on giving up recommending dust mite
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"What's important to understand is that avoidance measures are
very important for allergy controls, and one of the three ways we
treat allergies by avoiding your allergies, medication and
immunotherapy or allergy shots," said Friedlander, who was not
involved in the new study.
"This article is helpful to show a single measure to control
allergies is not always effective - we have to use multiple
measures," he said.
"So the take home message for me is that dust mite covers are still
very important, but they should be part of a comprehensive treatment
plan," he said.
Researchers try to modify one thing at a time, to show a cause and
effect, but in real life, allergists make multiple recommendations
necessary to resolve patients' symptoms, Friedlander said.
"If you do a single thing like dust mite covers, but you're still
exposed to dust from other sources in your house or work, or if you
have other allergies like pets or pollens, then of course a single
measure like dust mite covers is not going to be effective," he
Friedlander said he doesn't want people to think that dust mite
covers are not important.
"I think the point is that we need to make multiple recommendations
to relieve multiple allergies that our patients are allergic to," he
said. "Dust mite covers are very important, but they have to be part
of a comprehensive treatment plan."
It's important to see an allergist to determine what your allergies
are, Friedlander added, so the allergist can make a treatment plan
to take care of all of your allergies.
SOURCE: http://bit.ly/1dtFL1U Annals of
Allergy, Asthma and Immunology, online January 30, 2014.
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