Asthma & Dust Mites

Dust Mite Facts

  • Dust mites are bugs that belong to the spider family. They are so small they can only be seen with a microscope.
  • All homes in Manitoba have dust mites. Most dust mites are found in mattresses and pillows. They also live in carpets, furniture, stuffed toys, or other fabric materials.
  • Dust mites are a common cause of allergy problems.
  • Dust mites live up to 4 months. Each female can lay 100 eggs.
  • Dust mites eat dead skin flakes and produce waste called fecal pellets.
  • One mite may produce 20 fecal pellets a day. The pellets remain long after the mite is gone.
  • Allergy problems are mainly caused by these fecal pellets.
  • Dust mites like to live in warm, moist places (temperature 20 - 25' C, humidity above 50%).
  • Anyone allergic to dust mites should try to avoid them. This may decrease problems and the need for medicine.


Decreasing Dust Mites

  • At least 1/3 of a child’s time is spent in the bedroom. Focus on this room.
  • Encase the mattress and pillow with an airtight, mite-proof cover. Covers come in a range of prices.
  • If dust mite-proof covers cost too much, wrap the mattress in heavy plastic. Seal all seams with tape. Use a fitted, washable, quilted mattress cover for comfort over the plastic. Wash it with the bedding (sheets, blankets, pillow cases).
  • Place bedding over the dust-mite proof cover. Wash bedding once a week in hot water. Dry in a hot dryer for at least 45 minutes.
  • Put unwashable items, such as pillows and comforters, in the dryer on the hot cycle for 45 minutes every two weeks. Replace pillows every 2-3 years.
  • If possible, avoid carpets, espeically in the bedroom.
  • Keep humidity below 50% in the home.
  • Avoid clutter in the bedroom. Remove dust collectors.
  • If a child has a favorite stuffed toy that cannot be washed, place in a hot dryer for 45 minutes every two weeks.
  • Vacuuming removes only surface dust. Live mites are hard to vacuum. 
  • Air cleaners are not helpful in removing dust mites or fecal pellets.
  • Do not use a humidifier in the bedroom. If humidity in the home is high, use a dehumidifier.
  • Clean all hard surfaces at least once a week with a damp cloth.
  • Putting things in the freezer will kill the dust mites but it does not get rid of the fecal pellets.
  • If a child has an allergy to dust mite, their bedroom should not be in the basement.


Buying a Dust Mite Cover

  • Many stores sell covers that say they protect against dust mites. Not all covers do.
  • Covers must completely enclose the mattress, not just cover the top.
  • Openings in the material called pores should be less than 5 microns. Less than 2 microns is best.
  • Covers that allow air to move through the material are air permeable. Air permeable covers cost more, but will be more comfortable.
  • Vinyl and other low cost covers can be found at most stores that sell bed linen. More expensive covers can be obtained through specialty stores.
  • Speak to your Certified Asthma Educator or health care provider, if you need further information.


The Children's Allergy & Asthma Education Centre © 2011, 2014