Description
Dust mites are microscopic creatures, related to ticks and spiders, that live in house dust. The proteins in dust mite body parts and feces cause allergic reactions in people who have become sensitized to dust mite proteins. Dust mite allergen also triggers asthma attacks and is one of the most important causes of asthma attacks worldwide. Exposure to dust mites may also cause the onset of asthma. This is primarily because dust mites are found nearly everywhere, especially indoors. Therefore, exposure is constant.
All homes contain some amount of dust mites. The amount varies depending on the moisture and temperature in the home. Dust mites thrive in humid, warm environments. Because dust mites feed on dead human skin, the allergen tends to be concentrated in mattresses, bedding, upholstered furniture and carpets. They are very common in stuffed animals.
Additionally, pets that have fur or feathers contribute dander to the dust and increase the food source for mites.
Health Effects
Immediate Health Effects
- If SWALLOWED, Dermatophagoides pteronyssinus, D. farinae is Not Available
- If ABSORBED THROUGH SKIN, Dermatophagoides pteronyssinus, D. farinae is Not Available
- If INHALED (SNIFFED OR BREATHED IN), Dermatophagoides pteronyssinus, D. farinae is Not Available
Longterm or Delayed Health Effects
- This chemical may cause cancer. It is considered a Possible Carcinogen by the World Health Organization, the U.S. Environmental Protection Agency, or another agency.
- Allergen
- Asthma Trigger
Other
- Typical allergy or hay fever symptoms, such as sneezing, runny nose or congestion, sore throat, sinus pain, itchy or watery, red eyes, headache.
- Asthma symptoms, such as wheezing, coughing, difficulty breathing, tightness in the chest.
- Eczema or skin rashes in infants and young children.
How Exposures Occur
Bedding and Mattresses
- Dust mites concentrate especially in bedding and mattresses, where children are exposed to dust mite allergen by inhaling it in dust particles.
Carpets
- Children can inhale dust mite allergen in dust particles that settle and collect in carpets.
Upholstered Furniture, Cushions and Other Soft Furnishings
- Children can inhale dust mite allergen from dust particles collected in furniture upholstery, cushions, draperies and other fabric furnishings.
Stuffed Animals
- Children can breathe dust mite allergen from dust particles collected in stuffed animals.
Airborne Dust Particles
- Dust mite allergen can also be inhaled while it is airborne, though it tends to settle quickly.
Significant Statistics
Dust mites are present to some degree in nearly all human habitations.
“National Survey Examines Factors Related to High Levels of Dust Mite and Cockroach Allergens in Beds.” National Institute of Environmental Health Sciences, National Institute of Health, May 22, 2001.http://www.niehs.nih.gov/oc/news/atszeld.htm
Dust mites may be a factor in 50 to 80 percent of asthmatics.
Lyon, William F. House Dust Mites, HYG-2157-97. Ohio State University Extension Fact Sheet, Entomology, Ohio State University.
http://www.ag.ohio-state.edu/~ohioline/hyg-fact/2000/2157.html
A typical used mattress may have anywhere from 100,000 to 10 million dust mites inside. Ten percent of the weight of a two-year-old pillow can be composed of dead mites and their droppings.
Lyon, William F. House Dust Mites, HYG-2157-97. Ohio State University Extension Fact Sheet, Entomology, Ohio State University.
http://www.ag.ohio-state.edu/~ohioline/hyg-fact/2000/2157.html
High levels of dust mite allergens were found in bedding in 23 percent of homes sampled in the First National Survey of Lead and Allergens in Housing. Approximately 23.2 million U.S. homes have dust mite allergens at levels associated with asthma and allergies, this data suggests.
“National Survey Examines Factors Related to High Levels of Dust Mite and Cockroach Allergens in Beds.” National Institute of Environmental Health Sciences, National Institute of Health, May 22, 2001.
http://www.niehs.nih.gov/oc/news/atszeld.htm
Solutions
How to detect Dermatophagoides pteronyssinus, D. farinae
- It is impossible for us to detect dust mites by visual inspection, because they are so tiny. Even when dust particles are not visible, it is possible that dust mite particles linger. Laboratory tests are available to determine if levels are high, but generally this is unnecessary as we can assume that dust mites are present in all homes.
How to minimize exposure to Dermatophagoides pteronyssinus, D. farinae
- Eliminate or “Encase” Dust Mite Reservoirs:
• Remove Carpets: Wall-to-wall carpeting and padding are a significant dust mite traps, which release the allergen when disturbed by foot traffic and other movements on them. If possible, remove such carpets. Hardwood, tile and linoleum are much safer options. See Floor Coverings for information.
If you can’t live without carpet, choose natural fiber area rugs that can be cleaned easily. Short-pile rugs are the best. Try not to place the carpet on concrete. The warm space between a rug and concrete is a good place for mites to live. For more carpet and rug buying tips, see Carpets and Rugs.
• Encase mattresses in dust mite-proof covers. Tightly woven “barrier cloth” or airtight plastic-backed fabric or polyurethane covers should be placed over mattresses, boxsprings, pillows and comforters. Tape over the zippers with electrical or duct tape. Fabric encasements should be washed in very hot water (130 degrees Fahrenheit), while plastic encasements should be washed or damp sponged, every two weeks.
• Replace pillows filled with feathers, down or foam with synthetic fillings such as Dacron®.
• Keep stuffed toys off beds. An excellent substitute is a little cotton blanket which can be washed regularly.
• For more information on dust mites and other asthma triggers, see
What Breeds Between the Walls: Allergens and Asthma Triggers
What Breeds Between the Walls: Reduce Biological Pollutants in Your Home
How to Create Better Breathing Space for Asthmatics.
- Keep dust mite exposure low by thoroughly cleaning, especially in homes with infants.
--Wash your sheets, blankets, mattress pads and pillowcases in very hot water (130 degrees F) every week. Curtains should also be washed regularly, though not necessarily as often as bedding.
--Limit the number of stuffed animals to 2 or 3, wash them once a month in hot water (130 degrees F), and dry thoroughly in a hot dryer for 20 minutes. You can also kill dust mites in stuffed animals that cannot be washed by wrapping the stuffed animal in a plastic bag and placing it in the freezer for 4-5 hours.
--Vacuum carpets and upholstered furniture at least twice weekly. Keep your child in another room during and for several hours after vacuuming, because dust may leak out of the vacuum through the exhaust and remain airborne. Open windows while vacuuming to disperse dust. Substitute multi-layered vacuum bags for regular single layer bags, and use a vacuum with a high-efficiency, or HEPA, filter. Do not use a “bagless” vacuum, as dust mite allergen will be released when the collection container is removed for emptying.
--Damp-wipe dusty surfaces and mop floors weekly, especially in homes with small children, who spend much of their time on the floor.
--Avoid steam-cleaning bedding, upholstery and curtains. While the steam will kill mites, it fosters future mite growth by increasing humidity in the fabrics.
--Ventilate your home.
--NOTE: Avoid using anti-dust-mite carpet treatments that contain tannic acid or benzyl benzoate, both of which are skin, eye and respiratory irritants that can make asthma symptoms worse.
- Dehumidify: Reduce indoor humidity to 30-50% by using an air conditioner or dehumidifier. Don’t put an aquarium, humidifier or other source of water in your bedroom.
- Clean or replace filters on furnaces and air conditioners regularly, as recommended by the manufacturer. Install filters on air ducts, if appropriate.
- Use an air purifier only as a last resort. These devices can help somewhat, but are ineffective if other measures have not been taken. Since dust mite allergen dust does not remain airborne for long, air purifiers are unlikely to remove much dust from the room. If you do purchase an air purifier, make sure it is adequate for the room size, and keep windows and doors closed while it is in operation.
Alternatives
- Use plastic or wooden furniture instead of upholstered furniture.
- Use pillows with synthetic fillings such as Dacron® instead of feathers, foam or down pillows. Use cotton blankets instead of wool or down blankets. Avoid down comforters and chenille bedspreads.
- Curtains: Substitute easy-to-clean blinds or shades for curtains. Don’t forget to vacuum these regularly on both sides.
- Heat from underfloor radiant heating systems will kill most mites on floors.
For More information
Books, articles, factsheets and reports
Olkowski, William, Sheila Daar, and Helga Olkowski. Common-Sense Pest Control: Least-Toxic Solutions for Your Home, Garden, Pets, and Community. Newtown, Conn.: Taunton Press, 1991.
Biological Pollutants in Your Home: CPSC Document #425. Consumer Product Safety Commission, Office of Information and Public Affairs.
http://www.cpsc.gov/cpscpub/pubs/425.html
Other government agencies
National Institute of Environmental Health Sciences
Office of Communications
P.O. Box 12233
Research Triangle Park, N.C. 27709
919-541-3345
http://www.niehs.nih.gov/airborne/prevent/mites.html
National Asthma Education and Prevention Program
NHLBI Health Information Network
P.O. Box 30105
Bethesda, Maryland 20824-0105
301-592-8573
http://www.nhlbi.nih.gov/about/naepp/index.htm
Nonprofit organizations
American Lung Association
1740 Broadway
New York, NY 10019
800-LUNG-USA or 212-315-8700
http://www.lungusa.org
Asthma and Allergy Foundation of America (AAFA)
1233 20th Street, NW, Suite 402
Washington DC 20036
800-7-ASTHMA or 1-800-727-8462
http://www.aafa.org
Allergy and Asthma Network, Mothers of Asthmatics, Inc.
2751 Prosperity Avenue, Suite 150
Fairfax, VA 22031
800-878-4403 or 703-641-9595
http://www.aanma.org
Other websites
