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Dust Mites and Allergies

mite-67638_640By Rajinder S. Hullon, M.D., J.D.

Distantly related to spiders, dust mites are tiny organisms that cannot be seen with the naked eye. They feed on dust containing human skin flakes and primarily live in places that tend to collect dust:  such as carpets  and upholstered furniture —  and even sheets, pillows, blankets, and mattresses. As many as 90% of people who have allergic asthma are allergic to dust mites. Some people are allergic to live dust mites as well as the decayed bodies of dust mites and their fecal material, often found in household dust.

Symptoms of dust mite allergy typically include: repeated and prolonged sneezing, an itchy, stuffed-up nose, a watery nose, and watery eyes. The eyes, throat, mouth, and even the ears may itch.

Reducing household dust and humid environments, where dust mites thrive, can alleviate or eliminate allergic symptoms.

It can be nearly impossible to eliminate dust mites entirely, but here are some ways to decrease dust allergens in your home:

  • Keep humidity as low as possible, preferably less than 50%. Eliminating any water leaks or sources of moisture around the house, particularly in the basement, will also help make your home more inhospitable to mold.
  • Use air-conditioning properly. Air-conditioning can effectively lower the humidity level; filters should be changed and cleaned on a regular basis.
  • Replace surfaces where dust mites can proliferate, such as carpeting as well as upholstered furniture  that has smooth surfaces. In particular, avoid using wall-to-wall carpeting.
  • Remove stacks of paper, blankets, and similar dust catchers. Store blankets in sealed plastic bins or bags in a closet or a room apart from living areas.
  • Use dust-mite impermeable covers for pillows, mattresses, and bed covers.
  • Wash bedding in water hotter than 130˚F at least once a week. This kills mites.
  • Vacuum and dust often, especially in bedrooms.


Because most dust mites are concentrated in surface dust, not airborne dust, air cleaners and filters are not very effective in reducing these allergens. Ion and ozone generators can remove dust particles from the air, but not from surfaces, where dust mites are most apt to be found. Ozone generators, which produce ozone at levels 10 times above what the U.S. Code of Federal Regulations specifies as safe, should be avoided.


Vacuum cleaners stir up dust, so wearing a dust mask when vacuuming can reduce allergen exposure. Newer Higher Efficiency Particle Arresting (HEPA) vacuums may not actually reduce the number of dust mite allergens, but the vacuum cleaners can reduce the amount of small-particle dust that vacuuming generates. This, in turn, reduces the amount of inhaled dust containing dust mites and their droppings.


An allergist-immunologist will ask about your:

  • medical history.
  • eating habits.
  • home and work environments.
  • pets.

A blood test may be ordered to confirm dust mite allergy diagnosed on the basis of a scratch test. The doctor performs this test by painting a small patch of diluted dust mite allergen onto the patient’s back or forearm and then uses a needle to scratch the skin beneath the allergen. Swelling or redness that develops within 15 to 30 minutes indicates that the patient’s immune system has responded to the allergen.

Allergy shots and prescription medicines may provide relief for patients with persistent symptoms.