Asthma and Dust Mites

Dust mites are bugs that belong to the spider family. They are so small they can only be seen with a microscope. All homes have dust mites. Most dust mites are found in mattresses and pillows. They also live in carpets, furniture, stuffed toys, or other fabric materials.

Asthma and Dust Mites

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 to 25’C, humidity above 50%). Anyone with a dust mite allergy should try to avoid them. This may decrease allergy 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, dust 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, especially 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.