Dust mites are semi-microscopic insect-like creatures that live on human and animal skin scales or dandruff. They tend to be most concentrated in the bedroom, although they can be found in all parts of the house. They generally live inside places that cannot be cleaned (mattresses, pillows, comforters, wall to wall carpeting, couches, etc.) especially where a food supply accumulates (mainly human and animal dander skin scales and protein from feathers). Dust mites are not found on exterior surfaces in a room, which is why ordinary cleaning procedures are ineffective in reducing levels in the environment.
While mites can be found in houses at all times of year, they grow the fastest in warm humid conditions (i.e. late summer). Particles derived from mites get into the air when is stirred up (i.e. sleeping on a bed or walking across a carpet). There often is an increase in allergy symptoms in the fall and early winter when houses are closed up, the heat goes on and the air becomes dry.
While it is impossible to get rid of mites from the environment entirely, certain measures can greatly reduce their concentration and hopefully get the levels below threshold for allergic symptoms. Environmental measures may take a period of months before they have an effect on your allergy symptoms. If you have other triggers to your symptoms then controlling only the dust mite will have a more variable effect on your symptoms. The principles outlined below are particularly important in the bedroom but they also apply to other rooms of your house. The primary objective is to remove or seal up the places where mites grow.
Ways to reduce dust mite exposure
There are many measures that are advocated to control dust mites but controlling the areas where they grow is the most important.
The bed mattress and pillows should be completely encased in a cover that does not let the tiny dust mite particles through. These and other measures will be discussed with you if you are found to have dust mite allergy.