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Allergy Home
ENT and Allergy Center of Missouri
Dust Mites

House Dust Mites
Dust mites are close relatives of  spiders, scorpions and ticks.  There are several species of dust mite, but the most common American species are Dermatophagoides pteronyssinus and Dermatophygoides farinae. Over 85% of asthmatics are sensitive to the house dust mite, making it one of the primary triggers of asthma attacks.

The main triggers are allergens in the waste pellets which mites excrete and which build up in soft furnishings, such as bedding, sofas, carpets or curtains. Vigorous activity, such as vacuuming, dusting, or even walking on soft furnishings can make the dust mite waste products become airborne. Dust mites are much smaller than the period at the end of this sentence, invisible, and their pellets are microscopic in size.  We inevitably inhale these particles and people who are sensitive to dust mites will suffer an allergic reaction.

Where Dust Mites Live
Dust mites are present in nearly all homes in areas where the relative humidity is greater than 50% for some portion of the year. "Photophobic" mites thrive in the dark, warm and humid environment found in pillows, mattresses, box springs, blankets, carpets and upholstered furniture.   Literally millions of mites can inhabit a single bed as it provides both a perfect condition for growth and their greatest food source, the shed scales from human skin.

The Dirt on Dust Mites

  • 84%:  percentage of U.S. homes with detectable levels of dust mite allergens in a bed.
  • 40:  pounds of accumulated dust per year in the avg home.
  • 40,000:  number of dust mites in a speck of dust
  • 44,000,000:  number of U.S. homes with dust mite levels large enough to trigger allergic symptoms.
  • 22,000,000:  number of U.S. homes with dust mite levels large enough to trigger asthma symptoms.
  • 2,000,000:  average number of dust mites in a bed.
  • 50-85%........estimated percent of Asthmatics where dust mite allergy is the major trigger
  • 3,800,000.......lost work & school days each year due to allergic  disease .

Steps to Control Dust  Mite Allergens

  • Enclose the mattress and box springs in a zippered dust-proof encasing. Dust-proof encasings have a layer of material that keeps the dust mites inside the encasing. Encasings are usually made of plastic or plastic-like materials. If there is more than one mattress in the bedroom all mattresses should be encased. It is recommended that cloth tape be placed over the encasing zipper.
  • Wash all bedding in hot (130° F) water, weekly.
  • Put the pillows in zippered dust proof encasings and/or wash the pillows weekly with the bedding.
  • Avoid lying on upholstered furniture or carpet

Other Helpful Suggestions

  • Remove carpeting from the bedroom.  Instead, use area rugs that can be washed.
  • Use wipeable wood, leather or vinyl furniture instead of upholstered furniture in the bedroom.
  • Vacuum rugs and carpets frequently with a Hepa filter vacuum cleaner. The person with a dust mite allergy should not vacuum or be in a room while it is being vacuumed.
  • Keep the indoor moisture low. The ideal humidity level is 30-40%. Use an air conditioner or dehumidifier in warm climates to decrease the humidity. Clean the dehumidifier regularly. Humidifiers/vaporizers are not recommended because they will increase humidity in the room and create a favorable environment for dust mites. If you must use a humidifier, clean it weekly to prevent mold growth.
  • Chemical solutions may be helpful. Acaricides  (a chemical that kills dust mites) must be applied regularly to carpeting or upholstered furniture. This solution will not remove any preexisting mite waste pellets.  A tannic acid solution, applied as directed, can help neutralize the allergen in mite waste.

Your healthcare provider may recommend additional medications, therapies or other environmental controls. Exposure to dust mites can make allergy, asthma and/or eczema symptoms worse in some people. To avoid these problems follow the above steps to decrease or eliminate exposure.

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