Mice at the Tail End of Your Asthma Woes
Mice Allergens Are Factors in Asthma in Urban and Non-Urban Homes Alike, Study Shows
WebMD News Archive
March 17, 2008 (Philadelphia) -- Your old house could be at the root of
unexplained allergy and asthma symptoms, new research suggests.
A nationwide study shows that mouse allergens in U.S. homes -- once thought
only to be an inner-city problem -- are surprisingly common outside urban
Of more than 800 homes surveyed, 82% had detectable levels of mouse
allergen. More than one in three homes had levels high enough to increase the
risk that occupants would develop allergies.
And in people who already had allergies, elevated levels nearly doubled the
odds of having difficulty breathing, persistent wheezing, and other asthma
Elevated levels were most commonly found in high-rise apartments, mobile
homes, older homes, and low-income households.
Mouse Allergens: Risk Factors for Asthma
Exposure to mouse allergens is a well recognized risk factor for asthma in
the inner city, says William Busse, MD, head of the allergy section at the
University of Wisconsin in Madison and a former president of the American
Academy of Allergy, Asthma & Immunology (AAAAI).
But it's been overlooked as a risk factor outside of those settings, he
tells WebMD. Busse moderated a news conference to discuss the findings here at
the AAAAI's annual meeting.
The new findings grew out of the National Survey of Lead and Allergens, the
first study to estimate indoor allergens in a nationally representative sample
of U.S. households.
For this analysis, Paivi Salo, PhD, of the National Institute of
Environmental Health Sciences, and colleagues asked nearly 2,500 people living
in 831 households in 75 cities and towns nationwide about themselves, their
families, their living conditions, and their health, including whether they
suffered from allergies or asthma.
Dust samples were tested for mouse allergens from beds, sofas, and chairs,
and the floors of bedrooms, living rooms, and kitchens. Field teams inspected
each home for mice, cats, and other animals.
Kitchen Floors: High Concentration of Mouse Allergens
Kitchen floors had the highest mouse allergen concentrations of all the
places tested, Salo says.
Other mouse-allergen magnets included the bed and bedroom floor, the study
showed. Living room sofas and chairs had the lowest levels.
Don't think you're home free just because you don't see mice in your house,
Salo tells WebMD.
That's because mouse urine is the biggest source of the allergens, she
explains. "So even if you don't see mice, there are often mice allergens
left behind as the urine dries on dust particles."
So how do you know if there's a problem? In general, homes with lots of
cracks and crevices are the biggest offenders, she says.
Also, the older the house, the greater the likelihood that it harbors the
allergens, Palo says.
Doctors don't routinely test for mouse allergens, she adds. So if you have
unexplained symptoms of asthma, you may want to ask your doctor for a mouse
skin prick test.
The solution, of course, is to rid your home of mice, but that may not be as
simple as getting a cat. The researchers found no evidence that cat
owners had lower levels of mouse allergen in their homes.
But Salo notes that other research has shown that getting a cat could help
nip the problem in the bud. And it certainly won't hurt -- unless of course
you're allergic to the cat.