What Are Dust Mites?
Dust mites are microscopic, insect-like pests that generate some of the most common indoor substances—or allergens—that can trigger allergic reactions and asthma in many people. Hundreds of thousands of dust mites can live in the bedding, mattresses, upholstered furniture, carpets or curtains of your home. They feed on the dead human skin cells found in dust.
Dust mites are not parasites; they don't bite, sting or burrow into our bodies. The harmful allergen they create comes from their fecal pellets and body fragments. Dust mites are nearly everywhere; roughly four out of five homes in the United States have detectable levels of dust mite allergen in at least one bed.1
How Do Dust Mite Allergens Affect Health?
Mites are one of the major indoor triggers for people with allergies and asthma. Dust mite exposure can even cause asthma. 2
Chronic, ongoing exposure to dust mites at home can dramatically impact the health of people with asthma and those who are allergic or particularly sensitive to mites. These allergens cause an immune system response, known as allergic rhinitis. A dust mite allergy can range from mild to severe. A mild case may cause an occasional runny nose, watery eyes and sneezing. In severe cases, the condition is ongoing, or chronic, resulting in persistent sneezing, cough, congestion, facial pressure or severe asthma attack. People with asthma who are sensitive to mites face an increased risk of flare-ups or an asthma attack. 3
Where Do Dust Mites Come From?
Dust mites occur naturally and can appear in nearly all homes. Humidity is the most important factor in determining whether a house has high concentrations of dust mites. Dust mites do not drink water like we do; they absorb moisture from the air. In areas with low humidity, like deserts, dust mites cannot survive.
Who Should Be Concerned about Dust Mites?
People with allergies to dust mites or with asthma triggered by dust mite allergies need to reduce dust mites in their homes. Older homes, homes located in regions with humid climates, lower income residences and homes where a musty or mildew odor is present are more likely to have high concentrations of dust mites. 1
Dust mite allergens, unlike pet allergens, do not usually stay airborne. They cling to particles that are too heavy to remain in the air for long. Dust mite allergens settle within minutes into dust or fabrics, such as pillows, bedding or upholstered furniture, which serve as nests. Most exposure to dust mite allergens occurs while sleeping and when dust is disturbed during bed-making or other movement. 2
How Can Dust Mites Be Eliminated?
You can take action to reduce or eliminate dust mites in your home.
- Reduce humidity. To minimize growth of dust mites, keep your home below 50 percent humidity. In humid areas, air conditioning and dehumidifiers can help. On dry days, open your windows for one hour per day to help remove humidity from the house. 2
- Reduce the places where dust mites can grow. Remove some of the furniture or use furniture with smooth surfaces, eliminate drapes and curtains, and cover mattresses and pillows to reduce dust mites. Wash bedding in hot water once a week.
- Replace carpets. Carpeting should be removed from the home, especially if occupants are allergic to dust mites. If this is not possible, chemical cleaning of carpets with benzyl benzoate may reduce dust mites. 2
- Damp mop floors often. If you must retain the carpet, use a vacuum cleaner with a high efficiency filter or a central vacuum cleaner. When dusting, use a damp mop or damp cloth to reduce the amount of dust stirred up when cleaning.
- Arbes, Samuel J., Richard D. Cohn, Ming Yin, Michael L. Muilenburg, Harriet A. Burge, Warren Friedman and Darryl C. Zeldin. "House Dust Mite Allergen in U.S. Beds: Results from the First National Survey of Lead and Allergens in Housing." Journal of Allergy and Clinical Immunology 111.2 (2003): 408-14.
- Institute of Medicine, Division of Health Promotion, Indoor Air and Disease Prevention. Clearing the Air: Asthma and Indoor Air Exposures. Washington, D.C.: National Academies Press, 2000; Kanchongkittiphon W, et al. Indoor Environmental Exposures of Asthma: An Update to the 2000 Review by the Institute of Medicine. Environmental Health Perspectives. 2015; 123: 6-20.
- California Air Resources Board (CARB). 2005. Report to the California Legislature: Indoor Air Pollution in California. Sacramento, CA: California Environmental Protection Agency.
- U.S. Environmental Protection Agency. Asthma Triggers: Gain Control Dust Mites. Accessed August 26, 2015.