Dust & Dust Mites – Causes, Signs and symptoms

Dust Mites

Also called: Dust Allergies, Dust Mite Allergies


Dust allergies are among the most common allergic disorders. Dust is made up of tiny particles that include pollen, mold, fabric fibers and dander. A person who is allergic to any of these allergens may experience symptoms, such as sneezing, runny nose and itchy, watery eyes, when exposed to dust. Dust can also trigger symptoms in people with asthma.

Tiny organisms called dust mites are the source of many dust allergies. These eight-legged, microscopic creatures live in dust, and their feces are a powerful allergen for many people. Dust mites feed off the dead skin shed by people and can be major household irritants, particularly in bedrooms.

There are several steps that individuals can take to reduce their household exposure to dust and dust mites. However, those with moderate to severe allergies may need medications or allergy shots (immunotherapy) to keep symptoms at bay.

About dust & dust mites

Dust is an unavoidable part of life. Practically every activity in life generates dust. A human sitting at rest generates 100,000 dust particles per cubic foot of air every minute. The act of walking generates another 10 million particles per cubic foot of air every minute.

Household dust contains tiny particles of pollen, mold, fabric fibers, dander and dust mites. Dust can produce symptoms in individuals who are allergic to any of these allergens. However, dust mites are the source of most dust allergies.

Relatives of the spider, dust mites are microscopic arachnids one-third of a millimeter long that live indoors in household dust. Between 100 and 500 dust mites typically inhabit a single gram of dust, though in some cases the number can soar to 19,000.

Dust mites do not bite, spread disease or actually live on humans. However, dust mite feces contain a protein that is a powerful allergy trigger for many people. Each mite produces waste that is up to 200 times its body weight. Over time, the waste dries up and turns to powder, allowing it to become airborne. When an allergic person inhales the powder, an allergic reaction or asthma attack often follows. According to the Asthma and Allergy Foundation of America, about 20 million Americans are allergic to dust mites. The allergen is one of the most common causes of year-round allergy and asthma symptoms.

Dust mites are tough to eliminate because they have pads at the ends of their legs that allow them to firmly attach to the fibers in carpeting, upholstery and mattresses. They are found in great quantities in the bedroom, where they feed off the dead skin cells that people constantly shed. The average adult sheds enough skin each day to feed one million dust mites.

House dust mite populations tend to be smaller in areas at higher elevations (e.g., Rocky Mountain states), mostly due to the lack of moisture in these regions. Exposure to low humidity levels or extreme temperatures will kill most dust mites.

Potential causes of dust allergies

Dust springs from almost every corner of life. Matter that disintegrates eventually reduces to the particles that end up in dust, which can then become airborne. Many common allergens find their way into household dust, including:

  • Molds
  • Cockroach debris
  • Dead dust mite debris
  • Tobacco smoke and its toxic byproducts
  • Fibers
  • Food particles
  • Pollens
  • Plant and insect parts
  • Hair, animal fur and feathers
  • Dried pet saliva or urine
  • Flakes of human skin and animal dander

Dust mites are microorganisms that thrive in settings where moisture and dust are abundant. In the United States, dust mite populations tend to peak in the warm, humid weather months. However, their fecal allergens remain present at high levels for months afterward, into early winter and beyond. Dust mites tend to congregate in the following areas:

  • Mattresses and box springs
  • Drapes and curtains
  • Bed sheets, comforters, canopies and ruffles
  • Clothing
  • Upholstered furniture

Related allergies and conditions

Dust is a common allergen that affects many people year-round. It can produce symptoms in people with allergies, asthma or both. Conditions closely linked to dust allergies include:

  • Allergic rhinitis. Commonly called hay fever, allergic rhinitis is an inflammation of the inner lining of the nose that occurs when an allergic individual encounters an airborne allergen such as pollen, mold, dust mites or animal dander. Usually inhaled, these triggers generate allergy symptoms such as sneezing, coughing, runny nose, sore throat, and itchy and runny eyes.
  • Asthma. A chronic inflammation of the body’s bronchial (airway) tissues that afflicts millions of people in the United States. Dust mite allergies can trigger asthma attacks in some individuals. People with asthma experience shortness of breath, chest tightness, coughing and wheezing.
  • Allergic conjunctivitis. An allergic reaction of the eye to an allergen such as pollen, mold or dander. It involves an inflammation of the clear membrane that covers the white of the eye (conjunctiva) and can result in itching, burning, and redness in the eye. Swollen eyelids, watery eyes and eye discharge are also symptoms of allergic conjunctivitis.
  • Allergic bronchitis. An allergic inflammation in the lower airway of the respiratory system. It is a type of asthma, an inflammatory condition of the airways. Allergic bronchitis is also linked with allergic rhinitis. This occurs through the nature of the respiratory system, which is a continuum from the nose to the lungs.
  • Sinusitis. An inflammation of the sinus cavities in the face caused by infection, allergies or irritants. Symptoms include runny nose, headache, sensitivity in the teeth, nasal congestion and facial swelling.

Signs and symptoms of dust allergies

Symptoms of allergies to dust and dust mites are the same as those for allergic rhinitis. Though rarely life-threatening, untreated dust allergies can affect people on a daily basis throughout the year. Symptoms of dust allergies include:

  • Itchy, stuffy nose
  • Runny nose
  • Itchy, watery, red eyes
  • Sneezing
  • Breathing difficulties
  • Scratchy or swollen throat

Dust and dust mite allergies can also trigger asthma symptoms. Signs and symptoms of an asthma attack include:

  • Rapid breathing
  • Chest pain or tightness
  • Chronic coughing
  • Breathing difficulty (e.g., wheezing)
  • Shortness of breath
  • Fever
  • Headache
  • Stuffy head
  • Sneezing
  • Scratchy or sore throat
  • Itchy, watery eyes
  • Runny nose
  • Restlessness
  • Listlessness

Diagnosis and treatment for dust allergies

A physician will compile a medical history and a list of symptoms in trying to diagnose dust allergies. In addition, an allergy skin test may be performed. This test for allergies involves introducing a small amount of an allergen to the patient’s skin to determine if the person is allergic to that allergen. If a rash or small bump develops, the patient is most likely allergic to that substance.

Alternatively, a physician may order a blood allergy test. These tests look for the presence of allergy-specific immunoglobulin E (IgE) in the bloodstream. Blood tests are often used for patients who are not good candidates for skin testing, such as infants or individuals with skin disorders such as eczema. The most commonly used blood tests for allergy related conditions include the radioallergosorbent test (RAST).

The best way to reduce or eliminate allergic reactions is to avoid the allergen that triggers symptoms. There are many steps that can be taken to reduce exposure to dust inside the home. However, complete avoidance is very difficult, since dust is everywhere in the environment. Other treatments may be necessary for those with moderate to severe dust allergies.  

There are many over-the-counter and prescription medications that can treat the symptoms associated with dust allergies (e.g., runny nose, sneezing, watery eyes, skin rashes, difficulty breathing) including:

  • Antihistamines (prevent the release of symptom-causing chemicals into the body)

  • Decongestants (reduce nasal and chest congestion)

  • Corticosteroids and NSAIDs (reduce inflammation)

  • Bronchodilators (open breathing passages)

  • Mast cell stabilizers (prevent the release of symptom-causing chemicals into the body)

If medication treatment is unsuccessful, a physician may recommend allergy shots (immunotherapy). Allergy shots are a form of allergy and asthma treatment in which low doses of an allergen are injected into a patient over a period of time. The goal is to increase the patient’s tolerance to the allergen while reducing symptoms brought on by an allergic reaction.

Tips for controlling dust & dust mites

Dust and dust mites are a fact of life. There is no way to completely eliminate exposure to either. However, there are many ways to limit the amount of dust and dust mites that accumulate in a household. These include:

  • Keep indoor relative humidity below 50 percent. Because dust mites have no means of drinking, they depend on the atmosphere for moisture and thrive only in warm, humid conditions. Using air conditioning and dehumidifiers can help reduce humidity.

  • Use HEPA filters and other air filters that can be attached to a furnace or placed in a room to capture allergens and keep them from circulating in the air. It should be noted, though, that some experts question whether the relatively modest effectiveness of these filters justifies their expense.

  • Frequently wash and/or replace air filters for heating and air conditioning systems to prevent the spread of dust and other allergens throughout the home.

  • Thoroughly dust and vacuum the home at least once a week. It is especially important to clean bedrooms frequently because they are a haven for dust mites.

  • Wear a filtering mask when dusting or vacuuming. Better yet, have a nonallergic individual clean the home.

  • Use special filters on vacuums (such as HEPA filters or multi-ply exhaust bags) that reduce the amount of mite waste that is recirculated in the air. After vacuuming an area, stay out of the room for 20 minutes. This allows dust and other allergens to settle.

  • When dusting, use damp mops and cloths to pick up all excess dust. Dry cloths should not be used to dust because they stir up allergens. 

  • Talk to your physician about the potential benefits and risks of specialty cleaning solutions containing benzyl benzoate or tannic acid. Benzyl benzoate kills dust mites and helps remove their waste from carpets, usually for at least six months. It comes in a moist powder than is sprinkled onto carpets and allowed to dry for eight to 12 hours. Then, it is vacuumed up. Tannic acid kills dust mite allergens when sprayed on carpets and upholstered furniture, but does not kill the dust mites themselves. It must therefore be used much more frequently. There are risks associated with use of these chemicals, including the chance of irritation that may mimic allergy symptoms. Therefore they should only be used as directed, with caution and after discussing the matter with a physician.

  • Wash bedding (including pillows) at least once a week in water that is at least 130 degrees Fahrenheit (54 degrees Celsius). This will kill most dust mites that are present. Bedding that is not washable can be dry cleaned or left overnight in the freezer to kill dust mites. Also, use synthetic bedding materials, as dust mites prefer wool, feathers and cotton.

  • Use allergen-impermeable covers on mattresses, pillows and box springs. These completely encase the mattresses and pillows and prevent mites and their waste particles from getting into the air. Tape over zippers.

  • Keep pets out of the bedroom at all times. Dogs and cats attract dust mites like magnets.

  • Use washable materials such as role-type shades for window coverings. Those who use curtains should choose lightweight materials, which hold less dust. Vacuum window treatments often and wash them every six weeks.  

  • Dry laundered sheets, blankets and rugs in the sun. Sunlight destroys dust mites. However, this is not a good idea for people who also have allergies to outdoor allergens such as pollen.

  • Frequently wash pets’ sleeping cushions and encase them in allergen-proof covers.

  • Avoid clutter. Do not keep large stores of books and newspapers, which collect dust. Also, avoid storing items under the bed.

  • Use plastic bags to cover clothes in closets, reducing dust accumulation. Closet doors should also be kept closed.

  • Try to limit the use of carpets and rugs, especially in the bedroom. Hardwood floors, tile and linoleum are easier to clean and keep dust-free. Low-pile carpets are preferable to deep-pile carpets. Frequently steam-clean carpets. Better yet, use throw rugs, which can be easily washed in hot water.

  • Consider leather upholstery, which is less attractive to dust mites than upholstered furniture.

  • Keep toys out of a child’s bedroom, as they are likely to accumulate dust. Avoid stuffed toys and store all toys in closed containers, such as a toy box.

  • Eliminate sources of other allergens that may end up in dust, such as molds (which can be reduced by fixing any leaks or other ongoing sources of water) and cockroaches (which need both food and moisture to survive).

Questions for your doctor

Preparing questions in advance can help patients to have more meaningful discussions with their physicians. Patients may wish to ask their doctors the following questions related to dust and dust mites:

  1. Do my symptoms indicate a dust allergy?

  2. What methods will you use to determine if I am allergic to dust?

  3. Do dust allergies pose a danger to my overall health?

  4. What are my treatment options? How effective are they?

  5. Am I a candidate for allergy shots?

  6. Are there any ways to limit the amount of dust and dust mites in my home? Can I ever completely get rid of dust and dust mites?

  7. Will the severity of my symptoms vary throughout the year? Are some weather conditions better for dust allergies than others?

  8. Would I benefit from using a HEPA filter?

  9. Are my children likely to develop dust allergies as well?
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