House dust mites are microscope bugs that primarily live on dead skin cells regularly shed from humans and their animal pets.
Dust mites are harmless to most people.
They don't carry diseases, but they can cause allergic reactions in asthmatics and others who are allergic to their feces.
Skin cells and scales, commonly called dander, are often concentrated in lounging areas, mattresses, frequently used furniture and associated carpeted areas, often harbor large numbers of these microscopic mites.
Since the average human sloughs off 1/3 ounce (10 grams) of dead skin a week. That gives dust mites a lot to eat. Cats and dogs create far more dander for dust mites to eat.
A typical mattress can contain tens of thousands of dust mites. Sick yet? Nearly 100,000 mites can live in one square yard of carpet.
Ready to convince your spouse to start bathing regularly? Did you know a single dust mite produces about 20 waste droppings each day, each containing a protein to which many people are allergic. Yuck!
The proteins in that combination of feces and shed skin are what cause allergic reactions in humans. Depending on the person and exposure, reactions can range from itchy eyes to asthma attacks.
And finally, unlike other types of mites, house dust mites are not parasites, since they only eat dead tissue. Gross, but true.
Where do they live?
Beds are a prime habitat (where 1/3 of life occurs). A typical used mattress may have anywhere from 100,000 to 10 million mites inside. (Ten percent of the weight of a two year old pillow can be composed of dead mites and their droppings.)
Mites prefer warm, moist surroundings such as the inside of a mattress when someone is on it. A favorite food is dander (both human and animal skin flakes).
Humans shed about 1/5 ounce of dander (dead skin) each week. About 80 percent of the material seen floating in a sunbeam is actually skin flakes.
Also, bedroom carpeting and household upholstery support high mite populations.
Symptoms of Allergies to Dust Mites
The protein substances in the dust mite feces produces antibodies in humans who are allergic when these are inhaled or touch the skin.
These antibodies cause the release of histamines which causes to nasal congestion, swelling and irritation of the upper respiratory passages.
The Mayo Clinic, WebMD and NIH collectively provide this list of typical symptoms of an allergy to dust mites;
You may experience all or just some of them:
Hay fever, Watering eyes, Runny nose, Sneezing,
Asthma, difficulty in breathing, Itchy, red or watery eyes,
Nasal congestion, Itchy nose, roof of mouth or throat,
Postnasal drip, Cough, Facial pressure and pain,
Swollen, blue-colored skin under your eyes,
In a child, frequent upward rubbing of the nose
Detection
A doctor can use skin tests and blood tests to confirm a suspected dust mite allergy.
Since dust mites are present all year round, the symptoms of the allergy can be present at any time of the year, but are worst in months and seasons when the house is closed and the indoor humidity and temperatures are high (which, depending upon the household's use of heating and air conditioning, can be any time of the year).
The dried dust mite feces becomes airborne when someone walks over a rug, sits down in a chair, or shakes the bed clothes, making allergic person's symptoms worse.
House dust mite presence is often suspected before they are actually seen and accurately identified.
Requests for control often come from individuals who have been diagnosed by medical personnel as allergic to the house dust mite or the allergens produced.
The presence of house dust mites can be confirmed microscopically which requires collecting samples from mattresses, couches or carpets.
Also, it requires the use of a microscope with sufficient magnification and the technical ability to recognize house dust mites under the microscope.
In general practice, testing is unnecessary as dust mites are extremely common in household environments.
They virtually always show up in a test, so testing just adds expense.
A better question than "are dust mites present?" is "How can I control or remove them?"
