Allergic to WHAT?! Everything You (Never) Wanted to Know About House Dust Mites
Chances are nobody has ever told you the cold, hard truth about dust mites, but here it is. You have them. Everybody does. But what are they and why do we care? And what can we do about them?
What are dust mites?
Dust mites are tiny bugs (to be technical, they're actually tiny arthropods) that feed on human skin flakes. Because human skin flakes tend to accumulate in mattresses, pillows, carpets, upholstered furniture, blankets, clothes, stuffed toys and other fabric-covered items, those are the places dust mites tend to live.1 An average person sheds 1.5 grams of skin flakes every day, which may not seem like a lot, but that's enough to feed a million dust mites.2
They're too tiny to see, but most homes have them. They're on every continent except Antarctica.2 However, if you're allergic, you'll know they're there.
Why should we care about dust mites?
Dust mites don't bite or transmit disease, and since we can't see them and everybody has them, it's easy to assume that they're not that big of a deal. However, if you have allergies or asthma, dust mites can be a really big deal. Their body parts and droppings cause irritation in people who have an allergy to house dust mites.3 They're considered one of the most common environmental asthma triggers and most of us are exposed to them all year long.
The best way to find out if someone in your house is allergic to dust mites is to talk to your doctor, who will ask you questions about your symptoms and may order an allergy test to confirm whether or not you have an allergy. Symptoms of a dust mite allergy include sneezing, stuffy or runny nose, itchy or watery eyes, itchy nose postnasal drip, coughing, chest tightness or pain, difficulty breathing, wheezing – many of the common signs of asthma and allergies.2 A person who is sensitive to dust mites might not have all of these symptoms, but for people with asthma they can trigger an attack, and that is worth taking seriously.
But dust mites don't just worsen asthma. Evidence shows that exposure to dust mite allergens can even cause asthma in children who have not previously had asthma. New studies also warn that dust mites may make asthma worse for adults who were not already sensitive to dust mite allergens.4, 5
What can we do to prevent exposure to dust mites?
You've probably already figured out that if every home has them, there isn't anything we can do to permanently get rid of them. But there are a lot of things you can do to reduce your exposure to dust mites and make sure they don't cause problems for people with allergy or asthma in your home. Controlling house dust mites means preventing the growth of mites, as well as killing mites and then washing away dead mites and their droppings (since dead mite body parts and waste can still cause allergic reactions).
Listed below are some of the key steps recommended by the Institutes of Medicine, U.S. Environmental Protection Agency, Centers for Disease Control and Prevention and others to reduce the dust mites in your home. Use as many of these steps as possible in your home to provide the best protection:
- Keep the humidity in your home below 50 percent. Studies have shown that keeping humidity low may be one of the most important steps to preventing dust mites from multiplying. Air conditioners and dehumidifiers can help. If you live in a dry climate, open the windows to add ventilation.6
- Wash your bedding (sheets, blankets, comforters, pillowcases) in hot water once a week and make sure to dry all items completely before using them again. Water 130°F or hotter will kill dust mites.7
- Use special covers on pillows and mattresses that help to create a barrier between dust mites and the people using the pillows and mattresses. These are sometimes called dust-proof or allergen impermeable covers.
- Replace carpets with smooth, cleanable floors, like wood, tile or linoleum. If this is not possible, vacuum every week with a HEPA filter vacuum or central vacuum cleaner. You may also need to clean your carpets to reduce dust mites.4
- Choose washable items when possible. For instance, choose stuffed toys that can be washed in hot water and make sure to dry them completely before letting your child play with the toy again. To kill dust mites, you can also put stuffed toys in a plastic bag inside the freezer overnight.7 In general, avoid upholstered furniture or other items that provide a place for dust mites to accumulate.
- Dust often using a damp cloth and use a damp mop to clean floors. Using a dry cloth or dry broom can stir up dust and accidentally make it easier to breathe in. If the person doing the cleaning has a dust-mite allergy, he or she can also wear a filtering mask while cleaning to avoid breathing in excessive amount of dust mite allergen. People with allergies may also want to stay out of the room for a while after cleaning to avoid breathing in dust that has been stirred up.
If this all seems overwhelming, start by reducing the humidity in your home and controlling dust mites in your sleeping areas, because that's where we get the most exposure. But the more steps you can take, the less welcome dust mites will be in your home.
What else can I do to breathe easier?
Make sure your doctor knows that dust mites are a problem for you. If you've taken steps to limit your exposure to dust mites and you still find your allergies are causing problems, talk to your doctor about what else you can do. Certain over-the-counter and prescription medicines may help reduce allergy symptoms and help you keep your asthma under control. Your doctor may work with you to determine if you may have asthma or other allergies, as well.
People with asthma need to report continuing problems from allergies to their doctors, too. Your asthma can be managed and treated so you can live an active, healthy life.
The National Center for Healthy Housing (NCHH) is the preeminent national nonprofit dedicated to securing healthy homes for all. Since 1992, NCHH has served as a highly regarded and credible change agent, successfully integrating healthy housing advocacy, research, and capacity-building under one roof to reduce health disparities nationwide. NCHH is a 501(c)(3) nonprofit corporation based in Columbia, Maryland.
4Institute 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;
5Kanchongkittiphon 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.
6IOM, 2000. California Air Resources Board (CARB). 2005. Report to the California Legislature: Indoor Air Pollution in California. Sacramento, CA: California Environmental Protection Agency; Custovic A, Simpson A. 2012. The Roel of Inhalant Allergens in Allergic Airways Disease. J Investig Allergol Clin Immunol 2012: 22: 383-501