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House Dust Mite

Dust Mite Allergy

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  • Dust Mite Allergy
  • Signs and Symptoms
  • Diagnosis
  • Prevention
  • Treatment

If you have allergic symptoms like a runny nose, itchy eyes or cough, tiny creatures living in your home might be the reason for your problems. Although you cannot see them, you may be feeling their effects only too well.

They are, House Dust Mites and they live in many homes throughout the world.

What is a HDM?

Too small to be seen with the naked eye, a HDM measures only about one-quarter to one-third of a millimeter. HDM are close relatives of ticks and spiders. HDM do not bite people. They represent no danger to people who are not allergic to them (1,2).

Where are they found?

HDM trapped in the fibers of bed linens, furniture cushions and carpets. These materials also hold moisture well. Consequently, bedrooms are ideal habitats for HDM (3).

HDM are attracted to your bed because they live off the skin cells that we all shed each night. They also live in upholstered furniture.

Here is the problem: As you sleep, your skin sloughs off and works its way down into your bedding. An average adult person may shed up to 1.5 grams of skin in a day, this is enough to feed 1 million HDM. If the air in your room is humid, HDM get into your bed and pillow and happily grow into large colonies. Furthe rmore, your own bodycreates humidity as you breathe and perspire. Trying to kill the HDM will only have a limited effect, because the HDM faeces and the dead mite bodies remain and will still cause problems (4).

HDM Image

What is HDM Allergy?

HDM allergy is an allergic reaction to tiny bugs that commonly live in house dust. HDM may be the most common cause of year-round allergy and allergic asthma.

In people allergic to HDM, it is often not only the mite itself but also proteins in their droppings which cause the allergy. Each mite produces about 20 of these waste droppings every day and the droppings continue to cause allergic symptoms even after the mite has died (1,2).

References:

  1. http://www.aafa.org/display.cfm?id=9&sub=18&cont=228
  2. http://www.allergyuk.org/avoidingrespiratory-allergens/house-dust-mite
  3. http://www.mayoclinic.org/diseases-conditions/dust-mites/basics/definition/con-20028330
  4. http://www.mch.com/care-guides/dust-mite-allergy.aspx

What are the signs and symptoms of HDM allergy(1)?.

Mild Cases

  • Sneezing
  • Runny nose
  • 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
  • Frequent upward rubbing of the nose in children

Severe Cases

  • Difficulty breathing
  • Chest tightness or pain
  • An audible whistling or wheezing sound when exhaling
  • Trouble sleeping caused by shortness of breath, coughing or wheezing
  • Bouts of coughing or wheezing that are worsened by a respiratory virus such as a cold or the flu

What are the risk factors?

The following factors increase your risk of developing a HDM allergy (1) :

  • Having a family history of allergies

    You are more likely to develop a sensitivity to HDM if allergies are more common in your family.

  • Exposure to dust mites

    Being exposed to high levels of HDM, especially early in life, increases your risk.

  • Being a child or a young adult

    You are more likely to develop HDM allergy during childhood or early adulthood.

You are more likely to develop HDM allergy during childhood or early adulthood.

House Dust Mite

What are the various tests that can be done?

Your doctor may suspect HDM allergy based on symptoms, an examination of your nose,and your answers to his or her questions.

He or she may use a lighted instrument to look at the condition of the lining of your nose.

Your doctor may suggest an allergy skin test to determine what you are allergic to.

Skin prick test

The skin prick test involves:

  • Placing a small amount of substances that may be causing your symptoms on the skin, most often on the forearm, only in exceptional cases, the skin of the prostrate back can be used as an alternative.
  • The skin is then pricked so the allergen goes under the skin’s surface.
  • The health care provider closely watches the skin for swelling and redness or other signs of a reaction. Results are usually seen within 15 to 20 minutes.
House Dust Mite Diagnosis

Tiny amounts of purified allergen extracts —including an extract for HDM — will be pricked onto your skin’s surface. If you are allergic to dust mites, you will develop a red, itchy bump where the HDM extract was pricked onto your skin.

In some cases your doctor may order a blood test that screens your blood for specific allergy-causing antibodies to various common allergens, including HDM (1).

References

  1. http://www.mayoclinic.org/diseases-conditions/dust-mites/basics/definition/con-20028330

What preventive measures can you take?

There is probably no practical way to completely rid your home of HDM. But you can take action to lessen their effects.

Having HDM does not mean that your house is not clean. In most areas of the world, these creatures are in every house, no matter how clean. But it is true that keeping your home as free of dust as possible can lessen HDM allergy(1).

HDM Prevention

References

  1. http://www.aafa.org/display.cfm?id=9&sub=18&cont=228
  2. http://www.mch.com/care-guides/dust-mite-allergy.aspx

What are the treatment options available(1)?

The first treatment for controlling HDM allergy is avoiding HDM as much as possible. When you minimize your exposure to HDM, you should expect fewer allergic reactions or the reactions should be less severe. However, it is impossible to eliminate HDM from your environment. You may also need medications like antihistamines, corticosteroids etc to control symptoms.

The only causative therapy for HDM allergy is the allergen immunotherapy. You can “train” your immune system not to react exaggerated to an allergen anymore. This is done through a series of allergy shots called immunotherapy. One to two weekly shots expose you to very small doses of the allergen, in this case, modified/processed versions of the mite proteins that causes an allergic reaction. The dose is gradually increased, usually during a three-to six-months period. Maintenance shots are needed every four weeks for three to five years. Immunotherapy is usually used when other treatments like antisymptomatic medication are not satisfactory.

House Dust Mite Treatment

References

  1. http://www.mayoclinic.org/diseases-conditions/dust-mites/basics/definition/con-20028330
IND/04/17/ALGY/022/EXP 04/19