What has eight hairy legs and snuggles up with you at night? A dust mite. These too-small-to-see creatures live in household dust, and almost everybody has them.
When dust settles from the air or gets kicked up from the carpet, it lands on your sheets, pillowcases, covers, and quilts, and dust mites end up sleeping in your bed. Dust mites are a particular problem when household temperatures climb above 70 degrees and the weather is humid.
Millions of Mites
You can't see these microscopic dust mites or their droppings, but a used mattress may house up to ten million mites, and a two-year old pillow gets up to 10 percent of its weight from dead mites and the materials they leave behind! Add to that the pile of skin cells and oils you leave behind every night (which feed the mites), along with all the other household matter that ends up in dust particles, and you've got quite a mess in your bed.
But dust mites aren’t just unwelcome houseguests. They can cause respiratory problems for the approximately 20 million Americans who are allergic to mites or, more specifically, to the waste they leave behind. While they don’t bite, sting, or transmit disease, if you wake up often with red, itchy, or teary eyes, or a running or stuffed up nose, dust mites may be to blame.
Keeping the Mites Away
To keep your place free of mites:
- Encase your mattress and pillows in zippered, mite-proof covers. This will trap any mites that are already in your bedding, suffocate those that are still breathing, and prevent new mites from moving in. Covers will also keep out other allergens found in dust, such as other insect droppings, mold, pollen, and pet hair.
- Keep decorative pillows and stuffed animals off the bed.
- Frequently vacuum the surrounding area.
- Use a dehumidifier to keep humidity below 50 percent.
- Run a HEPA (high efficiency particulate arresting) air cleaner in an allergic person’s bedroom.
Keeping it Clean
Preventative measures are important, but new dust settles on surfaces every day, so wash all sheets and pillowcases in warm or hot water once a week, and all blankets, mattress covers, quilts and other bed covers almost as often.
Washing bed linens in water that is at least 130°F will kill mites. But according to Gerald Lee, MD, allergist with the University of Louisville, such a hot temperature may not be necessary. "Washing bed linens in warm (99°) water will remove most dust mites," he points out. "And it is recommended in order to avoid the risk of burns to children and other family members from scalding water."
Twenty minutes in a hot dryer will also kill most mites, adds Karen Calhoun, MD, allergist at The Ohio State University Wexner Medical Center in Columbus. Freezing and exposure to sunlight might also do the job, but these methods are not always practical or reliable, and won’t remove any residue mites leave on fabrics.
A Note on Dry Cleaning
Any bedding that cannot be washed at home, such as fine linens and wool blankets, should be dry cleaned at least once a year, and more frequently if you have allergies. Lorraine Muir, Director of Textile Testing and Research Services at the Drycleaning & Laundry Institute in Laurel, MD, suggests putting textiles in a plastic bag before bringing them to the cleaners. That will begin to kill off the mites; the dry cleaning and steam finishing processes will finish the job. It's also important to dry clean this type of bedding before storing, she adds.
Gerald Lee, MD, and Karen Calhoun, MD, reviewed this article.
Sources
Lee, Gerald MD. Email correspondence to author. Feburary 12, 2016.
Calhoun, Karen MD. Email correspondence with author February 11, 2016.
Muir, Lorraine. Drycleaning & Laundry Institute. Phone interview with author February 12, 2016.
"Dust Mite Allergy." Mayo Clinic. May 9, 2013.
Arbes SJ, Cohn RD, Yin M, et al. "House Dust Mite Allergen in US Beds: Results From the First National Survey of Lead and Allergens in Housing." J Allergy Clin Immunol 2003; 111(2): 408-414.
Calderon MA, Linneberg A, Kleine-Tebbe J, et al. "Respiratory Allergy Caused by House Dust Mites: What Do we Really Know?" Journal of Allergy and Clinical Immunology 2015;136(1):38-48.
Portnoy J, Miller JD, Brock Williams P, et al. "Environmental Assessment and Exposure Control of Dust Mites: A Practice Parameter." Ann Allergy Asthma Immunol. 2013; 111:465-507.
"Dust Allergy: Overview." American College of Allergy, Asthma & Immunology. Accessed February 1, 2016.
"Dust Mite Allergy." Asthma and Allergy Foundation of American. Accessed February 1, 2016.
"Dust Mites: Everything You Might Not Want to Know!" Environmental Health and Safety Online. Updated February 9, 2016.
Ogg B. "Managing Dust Mites." University of Nebraska Lincoln Extension. Accessed February 10, 2016.
