House dust mite (HDM) allergy is a hypersensitive reaction to proteins (allergens) in the excretion of dust mites. The concentration of the main allergen protein can outlast the dust mite itself as it is found in high concentrations in their faeces. Allergens derived from HDM faeces play a major role in allergic disease in many parts of the world, especially in childhood asthma. The rate of sensitisation to mite allergens is directly related to its exposure.In order to manage dust mite allergy it is necessary to reduce the amount of dust in your home and to try to reduce the dust mite population. This is best achieved using a combination of different measures.

Dust Mite Allergy

As an efficient scavenger there is no doubt that the dust mite has become one of the most prevalent domestic problems leading to many allergic reactions. As much as one tenth of weight of a two year old pillow is made up of dead mites and their droppings. Since the average human sheds between 5 to 10 grams of dead skin every week, there is a lot of food available for these scavengers. Dust mites are the second most common allergen after pollen so their impact upon our health is significant.

What is a dust mite?

A Dust Mite is a tiny, translucent, eyeless, eight-legged creature, measuring just 0.2 to 0.3mm in length. Dust mites consume several things but the main component of their diet is shed animal skin cells. Since the average human sheds around 1.5 grams of dead skin every week, the mites thrive in your bedding. A typical mattress may have anywhere from 100000 to 10 million dead mites. Dust Mites can leave up to 20 droppings a day (which they can also consume) and can produce up to 60-100 eggs. There are 2 common types of dust mites, the American dust mite D. farinae and the European dust mite D. pteronyssinus.

What is a dust mite?

Habits and Habitats

Dust mites contaminate their habitat with droppings and their shed skins, which are potent allergens for many people, as well as being a trigger for asthma. So it is of particular importance to reduce the dust-mite population in the home, particularly the bed. Dust mites don't live in every area of the home, as they need warmth and moisture to survive. As such they cannot actually live on hard floors or in the air, but their droppings and skins can be present there.

Mites, unlike cockroaches, are not capable of ingesting water; therefore in order to obtain water, they must absorb it from the air by secreting a salt solution from the upper part of their front legs and as such they thrive in humid environments, ranging from 55% to 75% relative humidity. As this solution makes its way to the mouth, it takes up water from the air. If the room gets too dry- below 50% relative humidity, the salt solution crystallizes, the mechanism shuts down, and the mites dehydrate. The growth of dust mites can vary on a seasonal basis, or from room to room within a house, depending largely on variations in relative humidity, availability of food sources, and temperature. A single adult female dust mite may lay up to 100 eggs. Mites take about one month to develop from an egg into an adult and have an adult life span of about two to four months.

The surface of a mattress is a favorite place for dust mites as it is warm, humid and has a plentiful supply of food- your skin! Clothing can be used by dust mites as a means of getting from one place to another around the house.

What is dust mite allergy?

House dust mite (HDM) allergy is a hypersensitive reaction to proteins (allergens) in the excretion of dust mites. The concentration of the main allergen protein can outlast the dust mite itself as it is found in high concentrations in their faeces. Allergens derived from HDM faeces play a major role in allergic disease in many parts of the world, especially in childhood asthma. The rate of sensitisation to mite allergens is directly related to its exposure.

HDM's feed on human skin scale in locations where it collects. We shed dead skin at a daily rate of 0.5 to 1.0g per person; this is more than enough for several thousand dust mites as they can survive for months on just 0.25g. HDM populations tend to flourish in the presence of moulds and it is thought that mould helps to break down and soften the skin scale. Another explanation is that mites feed on mould and gain nutritional benefit.

HDM's have been medically proven to trigger a whole host of allergic reactions, from Asthma, Allergic Rhinitis, Eczema and Bronchitis, to Itchy Eyes and Sneezing.

How do dust mites cause allergies?

When people with a family history of allergy are repeatedly exposed to house dust mite droppings, they can develop an allergy to dust mite. Unfortunately, exposure to dust mite allergens cannot be avoided, as they are present all year round. The microscopic droppings can be inhaled when they are airborne, causing respiratory symptoms. The powerful enzymes in dust mite droppings, designed to break down scraps of food, may also break down the protective lining of the lungs, nasal passages or lining of the eyes. Continued exposure to mite allergens can then become a trigger for chronic symptoms. As such, over exposure to the mites in beds and bedding is a major cause of allergy misery for millions of sufferers.

Dust mite mechanisms and physiology

A typical dust mite has a lifespan of approximately 90-120 days. Although the house dust mite lives for a maximum of three months, as a species it has been on earth for over 23 million years. As a scavenger the dust mite has evolved to survive on a wide range of food stuffs, and even considers its droppings as a source of nourishment. Its droppings, which consist of discarded or hard to digest food are put into parcels in their gut and encased in a dropping. Once outside the body of the mite, active enzymes go to work and breakdown the stubborn organic matter for future mite food. A healthy mite can produce between 20 to 30 droppings a day. On a moist surface these droppings dissolve and spill out their contents, which include active enzymes, fungi, bacteria, plant fibres, yeast and scales from insects and animals. Unidentified bacteria have also been noted growing prolifically on the wall of the mid gut of the house dust mite. Cells from this area are shed regularly into the debris that makes up the mite's droppings.

Though these mites live in many homes, only people who are allergic to them know they are there. When dust mites grow, they shed their skin. The shed skin and faeces are what cause allergic reactions in people. Allergic reactions range from itchy noses and eyes to severe asthma attacks.

Triggers

Household dust from mattresses, pillows, bedcovers, carpets, upholstered furniture, stuffed toys, clothes, or other fabric items in the home.

Symptoms

Dust mites cause symptoms similar to several other allergies such as Hay Fever, Asthma and Eczema, and are usually respiratory in nature. Therefore the most common respiratory symptoms usually include runny nose, blocked nose, sneezing and coughing which could also lead to an itchy throat and postnasal drip. The allergens can also cause itchy and watery eyes usually caused by a hypersensitive reaction to the dust mite allergens, and could lead to crusting of the eyelids.

Prevention

Important steps for Prevention and Control of Dust mites

In the bedroom

Considering we spend over a third of our lifetime in the bedroom, the first measure of prevention is to combat and reduce the dust levels here, since dust mites are known to thrive in mattresses, pillows and bedding. Here are some ways to reduce dust mites around the bedroom:

¢ Something as simple as leaving the bed unmade during the day releases moisture from the mattress, helping prevent dust mite growth.

¢ Anti allergy bedding prevents a new mattress or pillow from becoming infested. It can also be used on old mattresses to prevent the allergens from being released. This will effectively trap the dust mites within the mattress, deprive them of their food source- your skin- and consequently cause them to die.

¢ Make sure your duvet either has a built in allergy barrier or cover it with a dust mite proof cover. Top quality Feather Duvets, such as the Ringsted Dunn range have been tested and proven to be an effective dust mite barrier, as the cotton covers are so tightly woven and have a very small pore size.

¢ Wash bedding materials, including pillow cases, sheets, blankets and mattress pads every other week in hot water (130 °F), if possible, or use a specialized allergy detergent to neutralize allergens, such as the Allergymatters Laundry Detergent.

¢ Clean regularly using a HEPA filtered vacuum cleaner.

¢ Wash or steam and vacuum soft furnishings, such as curtains, or treat with the Allergymatters Anti Allergy Spray.

¢ Remove carpets where possible, or consider replacing with specially treated carpets that prohibit the growth of dust mites.

¢ Remove unnecessary toys, books, and stuffed animals, or keep stored in closed cupboards. Freeze soft toys that cannot be washed, at least once a month, to kill all dust mites.

¢ Hang all clothes inside wardrobes, including dressing gowns, instead of hanging them on the back of the door.

In the Home

Dust mite allergens can be spread in the air, and settle onto various surfaces, such as soft furnishings, carpets and clothing. The higher the concentration of dust mite allergen in your home, the more susceptible you are to develop this disease. Here are a few measures you can take to prevent your home from becoming a hot spot for dust mites:

¢ It is important to reduce humidity in your home because dust mites love high humidity.

¢ Try to get rid of steam after bathing or while cooking by opening windows and letting dry air into the house.

¢ Never re-use vacuum cleaner bags, and if possible use a vacuum cleaner with high filtration features. If you have a bag less model, make sure that a non dust mite allergic person empties it outside for you.

¢ Dust mites hate sunlight so air out your home and hang out rugs and blankets outside. Read our article on Heat and Dust Mites.

¢ Remove carpeting from rooms in the house and replace it with tiled or wooden floors. If you want to stick with carpeting, make sure you vacuum regularly with a good quality vacuum cleaner with HEPA filtration, or treat using a steam cleaner.

¢ Consider replacing old sofas with leather upholstered ones, as dust mites cannot live in them.

¢ Eliminate or reduce fabric wall hangings such as tapestries or pennants in the home.

¢ Damp dust the house regularly, not forgetting Venetian blinds, shelves, skirting boards and picture rails.

Treatment

In order to manage dust mite allergy it is necessary to reduce the amount of dust in your home and to try to reduce the dust mite population. This is best achieved using a combination of the following measures.

Dust mite management

Decreasing humidity - Dust mites love to be in high humidity environments therefore it is important to have humidity levels less than 50% in your home, especially in the bedroom. This can be achieved by using efficient Dehumidifiers to bring down the humidity.

Bedding - since the first point of defence in the home is in the bedroom, allergy free bedding has become one of the most effective ways to prevent contact with dust mite allergens and reducing symptoms. Research has shown that due to the small pore size of the covers for top quality feather filled pillows, dust mite allergens are prevented from entering or escaping the pillow and affecting sufferers. Allergymatters carries a wide range of Duck down pillows and duvets that allows you to get a good night rest. Click here for our wide selection of bedding suitable for you.

Heat Treatments - Using heat treatments such as steam cleaning and washing clothing at high temperatures neutralizes dust mite allergens. Efficient steam cleaners such as Allergymatters SteamBee Steam 'n' Vac neutralize allergens from carpets, floors and furnishing. Washing bedding weekly in hot water has been proven to be very effective at allergen removal.

Pets and Furnishings - Many people overlook the fact that pets with fur or feathers contribute to the dander in the dust and increase the food source for mites. If you are a pet lover, they can be kept clean using Anti Allergy shampoos. Ensure your pets bed is easy to clean, and located as far away from you as possible, such as a utility room or kitchen. When choosing replacement sofas, consider buying leather, as dust mites cannot survive within these. Carpets should be removed where possible, or treated regularly by vacuuming, steam cleaning and treating with anti allergy solutions.

Kids Toys - Put kids toys in the freezer once a month to kill dust mites if they can't be washed.

Dust management

Vacuuming - Possibly one of the most important tools for managing house dust mites is the vacuum cleaner. Regular vacuuming of carpets, furniture, textiles and other home furnishings such as curtains will help keep dust mite populations low. When buying a vacuum cleaner it is important to think not only about its filtration, whether it has a HEPA filter, and the level of suction power, but also the method of dust entrapment. Vacuum cleaners should have bags that have dense walls and secure seals, to prevent any dust from escaping, and should be easy to remove and dispose of so you don't get exposed to allergens when changing the bag.

Clean Indoor Air - The air you breathe in your home can be filled with millions of microscopic dust mite allergens which float in the air, particularly when settled dust is disturbed when cleaning. Air conditioners and Air coolers that have high efficiency filters are very useful; as they can clear airborne particles, reduce humidity and lower ambient temperature. Studies have shown air conditioned homes have ten times fewer dust mite allergens than non-conditioned homes, read our article discussing House Cleaning and Dust Mites. Air Purifiers play an important role in filtering out dust particles from the circulating air as well. But be careful in your choice of air purifier- HEPA air filters are known to be much more effective at removing dust than ion- generating air purifiers.

Management in the body

Several of the symptoms of dust mites are similar to common allergies such as Hay Fever, Asthma and Eczema, this is mainly because the mechanism of allergens such as pollen, dander or other particles seems to affect the body in a similar way, hence some of the treatments within the body can be tackled with same remedies.

Anti histamines help to block the action of histamine, a substance that is produced by IgE an antibody that causes many of the symptoms in these allergies.

Topical remedies can be applied directly to the skin and can help tackle eczema, which seems to be related to dust mites. Read our article on The relationship between Dust Mites and Eczema.

Decongestants give relief from several of the respiratory symptoms in the nose, eyes and throat and help to suppress the production of histamine.

Herbal remedies, which can include some herbs that have natural anti histamine properties and several other plant extracts, can help to reduce the overall symptoms of dust mite allergy.