High levels of airborne mouse allergen in inner-city homes could trigger asthma attacks

February 10, 2005

The amount of mouse allergen found in the air in many inner-city homes could be high enough to trigger asthma symptoms in the children who live there, say researchers at the Johns Hopkins Children's Center. Their study, published in the February issue of the Journal of Allergy and Clinical Immunology, found more than a quarter of inner-city homes sampled had airborne allergen levels already known to aggravate asthma symptoms in animal research lab workers with mouse allergy.

"Children living in inner-city homes are continuously exposed to the allergy-causing substance found in mouse urine that is circulating in the air," says Elizabeth Matsui, M.D., a pediatric allergist at the Johns Hopkins Children's Center and lead author of the study. "This exposure increases their risk for developing allergic sensitivity to mice, just as it does for laboratory workers who constantly work with rodents."

Other common household allergens known to affect asthma include proteins shed by cockroaches, dust mites, furry pets and mold, along with tobacco smoke and certain chemicals. While previous studies have examined exposure to settled dust mouse allergen in inner-city homes, this is believed to be the first to describe airborne mouse allergen levels.

Once sensitized, such children exposed to airborne mouse allergen at the high levels found in the study may be more likely to experience asthma symptoms, including wheezing or difficulty breathing, which could lead to a full-blown asthma attack or other asthma-related illnesses, Matsui said. "Because asthma attacks have the potential to be life-threatening, these findings are of some concern," she adds.

The researchers report airborne mouse allergen was most likely to be found in homes with cracks and holes in walls or doors, exposed food in the kitchen, or evidence of mouse infestation, such as droppings. Although mouse allergen is most prevalent in inner-city homes, Matsui says previous studies have also detected it in approximately 75 percent of middle-class suburban homes.

"One of the best ways parents can manage their child's asthma is to control the home environment and remove any asthma triggers, including mouse allergen," she adds. "They can do this by sealing cracks and holes in doors and walls, thoroughly disposing of all food remains, and having pest exterminators treat their home."

In the study, Matsui and colleagues collected air and dust samples from the bedrooms of 100 inner-city children with asthma and found 84 percent of bedrooms had detectable levels of mouse allergen. In 25 percent of these bedrooms, airborne levels of mouse allergen were 0.10 nanograms per cubic meter or higher, comparable to what is seen in mouse research facilities. All study participants were also tested for mouse and other allergies, and nine children were found to be sensitized to mouse and 69.7 percent of children had at least one positive skin test to other common indoor and outdoor allergens.

"Unfortunately, many clinicians do not take mouse allergen into consideration when evaluating inner-city children with asthma," Matsui says. "Testing these children for mouse allergy needs to become as routine as testing for allergies to cockroach or dust mites, and clinicians need to be ready to recommend aggressive extermination of mice or other ways parents can control the home environment."

Asthma affects approximately 15 million people in the United States, about a third of whom are children. It is the third-ranking cause of hospitalization for children 15 years and younger and is the leading cause of chronic illness among children. Researchers estimate that asthma is twice as common in the inner city in comparison to other areas.

The study was sponsored by the United States Environmental Protection Agency, National Institute of Environmental Health Sciences, and the National Heart, Blood, and Lung Institute. Co-authors include Elinor Simons, Arlene Butz and Peyton Eggleston from the Johns Hopkins Children's Center; and Timothy J. Buckley and Patrick Breysse from the Johns Hopkins Bloomberg School of Public Health.
-end-
Founded in 1912 as the children's hospital of the Johns Hopkins Medical Institutions, the Johns Hopkins Children's Center offers one of the most comprehensive pediatric medical programs in the country, from performing emergency trauma surgery, to finding causes of and treatments for childhood cancers, to delivering a child's good bill of health. With recognized Centers of Excellence in 20 pediatric sub-specialties including cardiology, transplant, psychiatric illnesses and genetic disorders, Children's Center physicians, nurses and staff provide compassionate care to more than 90,000 children each year. For more information, please visit: www.hopkinschildrens.org

Johns Hopkins Medicine

Related Asthma Articles from Brightsurf:

Breastfeeding and risks of allergies and asthma
In an Acta Paediatrica study, exclusive breastfeeding for the first 3 months was linked with a lower risk of respiratory allergies and asthma when children reached 6 years of age.

Researchers make asthma breakthrough
Researchers from Trinity College Dublin have made a breakthrough that may eventually lead to improved therapeutic options for people living with asthma.

Physics vs. asthma
A research team from the MIPT Center for Molecular Mechanisms of Aging and Age-Related Diseases has collaborated with colleagues from the U.S., Canada, France, and Germany to determine the spatial structure of the CysLT1 receptor.

New knowledge on the development of asthma
Researchers at Karolinska Institutet in Sweden have studied which genes are expressed in overactive immune cells in mice with asthma-like inflammation of the airways.

Eating fish may help prevent asthma
A scientist from James Cook University in Australia says an innovative study has revealed new evidence that eating fish can help prevent asthma.

Academic performance of urban children with asthma worse than peers without asthma
A new study published in Annals of Allergy, Asthma and Immunology shows urban children with poorly controlled asthma, particularly those who are ethnic minorities, also suffer academically.

Asthma Controller Step Down Yardstick -- treatment guidance for when asthma improves
The focus for asthma treatment is often stepping up treatment, but clinicians need to know how to step down therapy when symptoms improve.

Asthma management tools improve asthma control and reduce hospital visits
A set of comprehensive asthma management tools helps decrease asthma-related visits to the emergency department, urgent care or hospital and improves patients' asthma control.

Asthma linked to infertility but not among women taking regular asthma preventers
Women with asthma who only use short-acting asthma relievers take longer to become pregnant than other women, according to research published in the European Respiratory Journal.

What are the best ways to diagnose and manage asthma?
A team of experts from The University of Texas Medical Branch at Galveston examined the current information available from many different sources on diagnosing and managing mild to moderate asthma in adults and summarized them.

Read More: Asthma News and Asthma Current Events
Brightsurf.com is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.com.