Do you need to be concerned about house dust mites?


by Linda Alvarez-Thull, M.D.

Do you need to be concerned about house dust mites? Are these mites making your asthma or allergies worse? If so, how can you get rid of these creatures?

House dust mites (scientifically called Dermatophagoides pteronyssinus and D. Farinae) are microscopic mites that live in beds, carpets, sheets, sofas, and other furnishings or material that hold moisture. These scavengers feast on dead skin which is found in house dust. Dust mites are one of the most important allergic substances found in house dust. The essential ingredient for the livelihood of the mite is humidity. Generally, those environments in which humidity reaches 50% or more are the best habitats for these mites. If humidity is lacking, these creatures dry up, die, and eventually may become non-existent in a dry environment. In areas of the country where humidity is relatively high such as the southeast and east coast, house dust mites are ever-present, and very difficult to eradicate.

Exposure to this year-round allergen is responsible for much exacerbation of asthma and hay fever problems. In a person with asthma or an allergic predisposition, significant improvements may occur with dust mite control in the home. Extreme (but possible) measures must be taken to eradicate this allergenic hazard from the home. Measures include encasing mattresses, pillows, and bedding with impermeable covers, washing sheets in hot (130 degrees) water, selecting furniture with impermeable coverings such as leather, and choosing tile or wood floors as opposed to carpet. Chemicals that break down the allergic particles of the dust mite, or cause their demise, are available for the home. The most important measure is to maintain low humidity in the home.

So, do inhabitants of Arizona need to worry about house dust mites, since we supposedly live in a dry environment? Perhaps. Let’s take an example from a study done in Denver, Colorado, which is reportedly a low-humidity environment. Homes that used evaporative coolers were sampled for dust mites. These homes surprisingly had a measurable level of dust mites that was within the range for causing allergic problems. No formal study has been done in Arizona. However, it is likely that homes that use evaporative coolers on a consistent basis may support dust mite growth. In addition, humidity in some areas of Arizona is increasing due to increased moisture released into the air through irrigation and by air conditioners. Keep in mind also that dust mites may live as long as six months in furnishings brought in from humid environments.

What recommendations can be offered? If someone in your family has asthma or an allergic problem, taking measures to dust mite proof your home may not only eradicate a potential problem, but give you peace of mind that these pesky creatures are not hampering your health. Speak to your allergy specialist about your particular situation.

Posted in: Home Environment

Allergy and the Environment