Which avoidance methods are used to prevent allergic diseases caused by dust mite aeroallergens?

Updated: Jul 07, 2019
  • Author: Bhumika Patel, MD; Chief Editor: Michael A Kaliner, MD  more...
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Answer

Answer

Several studies show that using impermeable mattress covers is not an effective strategy by itself to reduce the symptoms of allergic rhinitis or asthma in dust mite-sensitized subjects. [10, 12] However, a study by Morgan et al demonstrates significant benefit of impermeable covers when used as part of a comprehensive and individualized allergen avoidance program. [13]

Impermeable covers are composed of either vinyl or tightly woven fabrics and serve as effective dust mite barriers. Because vinyl is impermeable to air, it tends to be hotter and less comfortable than a woven cover, which is more comfortable but, usually, more expensive. In addition, nonwoven mattress encasements accumulate mite allergen, in contrast to woven encasements. [14] In either case, the covers used should encase the pillows, box spring, and mattress. These coverings may be purchased from retail stores, Web sites (eg, www.natlallergy.com), mail-order catalogs, and allergy specialty stores.

Elimination of dust reservoirs

The removal of dust reservoirs remains an important part of the avoidance program, although it can be difficult and expensive. Removal of carpets, draperies, and upholstered furniture decreases mite exposure. Removal of stuffed toys, books, or other items that collect dust, particularly in the bedroom can be helpful.

Vacuuming

Weekly vacuuming is recommended, and vacuum bags should have 2 layers or a HEPA filter to decrease aerosolized allergen exposure because of the air disturbance. Individuals allergic to dust mites should try to avoid vacuuming or being present when the bag is changed. [95] The use of a pollen mask (eg, Nexcare All-Purpose Mask [3M, St Paul, Minn]) can also be helpful for sensitized individuals who are unable to avoid vacuuming.

Dehumidifiers

Because dust mites depend on a humid environment to live, reducing the relative humidity level to less than 50% can be helpful. [98] However, a level of relative humidity low enough to effectively restrict mite population growth is difficult to maintain in most locales. Central dehumidifiers are expensive and are not very effective, particularly in areas that have a high humidity all year. Bedroom dehumidifiers are not effective and are not recommended for routine use.

Washing

Dust mites have 90% to 98% mortality in cold water washing, indicating that most mites die by drowning. [92] Residential hot water should be set below 49º C (120º F) given the effectiveness of kiling dust mites at lower temperatures to prevent scalding of occupants. [98]

Drying

All dust mites were killed when a blanket was dried for 10 minutes, and 99% of dust mites were killed when a duvet (comforter) was dried for 1 hour in a clothes dryer. [93, 94]

Air purifiers

Air purifiers alone are not useful for dust mite allergen control because dust mites do not remain airborne for long periods. Thus, the routine use of air purifiers is not recommended because clinical benefits are not documented.

Freezing

Dust mites die when frozen; therefore, stuffed toys and other such items can be placed in a domestic freezer at -15º C (5º F) for at least 16 hours to decrease dust reservoirs. [91] In climates where the outside temperature drops below freezing, rugs, blankets, mattresses, or other items can be placed outside for 2-3 days to kill dust mites.

Acaricides

Studies investigating the use of acaricides on carpeting to kill dust mites have yielded mixed results. Benzyl benzoate kills 90% of mites in culture within 12 hours, however, these effects are short-lived and the acaricide on the carpet should be reapplied every 2-3 months. [89] Furthermore, a decrease in dust mite allergens in carpeting may not be clinically beneficial. [90]

Duct cleaning

Because dust mites do not typically reside in air ducts, cleaning air ducts does not decrease exposure.

Relocation

Although not very practical, moving to locations that are less favorable for dust mite growth can be beneficial. For example, high altitudes or arid locales are associated with less mite growth.


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