Extra Information

2.2 million people have asthma, including 1 in 6 children and 1 in 10 adults
Australia has the 3rd highest prevalence of childhood asthma in the world
397 died of asthma in 2002 and research has shown that approximately 60% of asthma deaths are preventable
Asthma costs the Australian community over $700 million each year – in terms of medical costs and lost productivity
Asthma is the leading reason children visit hospital
One million school days are lost nationally each year due to Asthma
Affects 14% of people under 20 and 11% of adults
Is more likely to affect boys (15%) than girls (12%)
The cause of asthma is unknown and there is currently no cure. However, a number of factors have been identified which increase the risk of asthma. Research continues into improvements in treatment and management and finding a cure
Regular physical activity is part of good asthma management. However exercise can trigger asthma if not properly managed

This information was provided by Asthma New South Wales

Asthma and allergic reactions TOP OF PAGE

The strongest risk factors for developing asthma and allergies are exposure to indoor allergens such as domestic mites (house dust mites) in bedding, carpets and stuffed furniture - The USA National Institute of Health.

Dust mites and their by-products are a major allergic factor and their control is essential in the management of asthma - Asthma and Allergy Foundation of America

The problem with dust mites TOP OF PAGE

Dust mites are so small that up to 2 million can live in your mattress. They thrive in warm, dark, humid conditions such as in mattresses, doonas, pillows, underlays, blankets, quilts, carpets and rugs, upholstered furniture, curtains, clothes, soft toys, as well as your vacuum cleaner.

Dust mites live on a diet of skin scales, which we shed daily, as well as animal skin and mould. They produce up to 50 faecal droppings a day, the most common cause of asthma and allergies. The only way to get rid of dust mite droppings is to get rid of house dust mites.

The Triggers of Asthma and Allergies TOP OF PAGE

No one is sure what causes asthma and allergies, but we do know there are certain triggers. The world’s authorities, such as Asthma Australia, Asthma United Kingdom and the Asthma and Allergy Foundation of America agree that major triggers of asthma and allergies include airborne pollens and grass seeds, house dust, house dust mites and their faeces and pet dander.

"The strongest risk factors for developing asthma are exposure to indoor allergens such as domestic dust mites in bedding, carpets, and stuffed furniture, cat dander and cockroach allergens." - (The USA National Institute of Health)

"The air we breathe may include particles that some people are allergic to, such as house dust mite, animal dander, pollens and moulds. When people are "allergic" their immune system reacts in an abnormal way to these specific particles when they inhale or touch them." - (Asthma Victoria)

"Particles from 2.5 to 10 microns in diameter tend to collect in the upper portion of the respiratory system affecting the bronchial tubes, nose and throat. Those below 2.5 microns in diameter can infiltrate into deeper portions of the lung and therefore remain in the body longer." - (F.J. Miller "Journal of the Air Pollution Control Association")

"75% to 85% of asthmatics have positive reactions to skin tests of house dust. Common house dust is composed of many asthma and allergy triggers such as animal danders, moulds, spores, pollen, dust mites, cockroach allergens. This confirms the long held idea that most asthmatics have an allergic component to their asthma." - (Asthma and Allergy Foundation of America)

How Can Exposure to These Triggers be Reduced? TOP OF PAGE

"Allergy and asthma triggers should be avoided wherever possible. For example, if house dust brings on asthma, try to keep the house as dust-free as possible."- (USA Department of Health and Human Services)

"Dust mites and their by-products are a major allergic factor and their control is essential in the management of asthma." - (Asthma and Allergy Foundation of America)

"Several studies have shown that if indoor allergen exposure can be reduced sufficiently, then asthma symptoms often improve. Also, reducing the allergen exposure in infancy reduces the risk of becoming allergic later and developing asthma." - (Asthma NSW, Australia)

Asthma NSW, Australia, recommends that exposure can be minimised by using correct furniture fabrics, making housing too dry for mites to breed in, and using effective cleaning methods.

Dust mites - biology under the microscope... TOP OF PAGE

Do you know what lives in your mattress?

The mattress on which you spend your nights, is just like a jungle.

Gigantic plants and moulds thrive quickly in your perspiration, about a litre of body fluid every night, creating a perfect breeding ground in your mattress for bacteria!

Dust mites in bed are almost impossible to observe with the naked eye, but they are certainly there, 2,000 - 15,000 of them per gram of dust.

As an appetiser, they eat the moulds which best helps them digest dead skin cells and those of your pets known as dander. In fact, it is your skin cells, which interests them. Every night you shed up to 1 gram of skin, a real treat for the mites, but not for you. The old adage "what goes in must come out" they defecate the remains of their food, up to 50 waste particles a day, the most common cause of asthma and allergies.

Research found many people are allergic to the protein in mites and faeces which can trigger rhinitis allergica or bronchial asthma attacks.

Deratophogoides Pteronyssinus, Latin translation "skin eating spider" or more commonly known as the house dust mite. Eight legged members of the arachnid family, related to spiders, ticks and lice.

They thrive in warm humid conditions and are less commonly found in dry high altitude areas. Dust mites do not drink water, but absorb water from the environment. They are hardy, surviving and multiplying best when relative humidity is 70-80% and the temperature is 20-21 degrees Celcius. Dust mite numbers increase during spring and reach a peak mid summer. They do not survive well at low relative humidities, especially at higher temperatures. Their population reduces during cooler months when the air becomes much drier due to internal home heating.

Dust mites thrive in mattresses, doonas, pillows, underlays, blankets, quilts, carpets and rugs, upholstered furniture, curtains, clothes, soft toys, as well as your vacuum cleaner. By scheduling mattress and carpet treatment during September and October, allergen can be effectively removed before accumulation becomes an exposure risk.

Adult female mites lay cream coloured eggs coated with a sticky fluid that helps them adhere. Life cycle from egg to adult is about 30 days. The proteins are so light that they float into the air when disturbed. The slightest movements, like simply ruffling bedclothes, are enough to cause large amounts of mite proteins to swirl into the air around us.

Dust mites in bed TOP OF PAGE

"Even when new homes and furniture are dust free, within a month they are polluted with dust mites. They come from other areas in which people spend time, such as their vehicles and other people's homes." - American Academy of Allergy, Asthma and Immunology.

Did you know that your pillow can be ten times heavier, five years after you first bought it? It has acquired living and dead dust mites, their faeces (droppings), mould spores, dead skin cells and moisture.

What is an allergen? TOP OF PAGE

An allergen is a substance that sets off an allergic reaction. For many people with asthma, exposure to a substance to which they are allergic (the allergen) makes their asthma symptoms worse. That is, exposure to this allergen 'triggers' their asthma.

Common allergens that trigger asthma include house dust mite faeces, skin flakes from pets especially cats ('cat allergen') and household moulds.

The asthma and allergy connection TOP OF PAGE

There is a range of scientific theories about the causes of asthma, some of which link exposure to high levels of common asthma allergens in early life with the subsequent development of asthma. However, other experts place less emphasis on the importance that allergens play in determining whether or not a person will develop asthma, as it has been shown that not everyone who develops asthma has had a high level of exposure in early life to common household allergens, such as those mentioned above. Equally, not every person who is surrounded by common asthma allergens early in life will go on to develop asthma.

It is, however, agreed that the causes of asthma are complex and are not completely explained by the presence or absence of common asthma allergens during early life. Nevertheless, many people who have asthma do have a demonstrated allergy (a positive allergy blood test or skin prick test) to one or more of the common asthma allergens, and continued exposure to this allergen may be triggering their asthma symptoms.

Can a low-allergen house make a difference? TOP OF PAGE

People who have asthma or whose children have asthma should consult with their doctor to find out if their asthma is triggered by an allergy (your doctor may want you to have blood tests called RASTs or undergo skin prick testing). Also, discuss with your doctor whether aiming for a low-allergen house is likely to help your asthma or your child’s asthma.

A low-allergen house aims to minimise exposure to common household asthma allergens and is based on the belief that minimising exposure to these allergens may improve asthma control and lessen asthma symptoms.

Some scientists also believe that a low-allergen house is less likely to result in babies in that house going on to develop asthma. This is particularly relevant if the parents have asthma, which indicates a genetic predisposition in that family to developing asthma.

Steps to take towards a low-allergen house TOP OF PAGE

Dust mites live where dust accumulates — in carpets, mattresses, bedding and pillows, soft furnishing and soft toys. They feed on the thousands of skin cells we shed each day and which become part of household dust. Steps you can take to reduce dust and dust mites include mattress and pillows cleaning, choosing vinyl or leather covered furniture rather than fabric covers, and choosing blinds over heavy dust-collecting curtains for windows. Hard flooring is a better option than carpet. Aim to wash pillowcases, sheets and blankets weekly in hot water (> 55°C), and regularly air doonas and other bedding in the sun (and wash in hot water every 6 weeks). Wash children’s soft toys in hot water regularly, or place in the freezer overnight to kill dust mites. Avoid having too many soft toys in the bedroom. House dust mite allergy, reviewed by Dr Paul Klenerman, specialist and Professor Brian Lipworth, professor of allergies and respiratory medicine.

What is house dust mite allergy? TOP OF PAGE

House mite allergy is a hypersensitive reaction to proteins in the excretion of dust mites. The protein attacks the respiratory passages causing hay fever and asthma. It will aggravate atopic dermatitis in people who have a tendency to this problem.

House dust mites are found in all homes. They are microscopic organisms that thrive in warm and humid houses with lots of food - human skin. The mites prefer to live in beds and, because we spend about a third of the day in bed, we inhale large quantities of dust mite allergens.

How do you become allergic to house dust mites? TOP OF PAGE

The excretion of the mites contains a number of protein substances. When these are inhaled or touch the skin, the body produces antibodies. These antibodies cause the release of a chemical called histamine that leads to swelling and irritation of the upper respiratory passages - typical asthma and hay fever symptoms. The predisposition for allergy is often hereditary.

Unlike pollen, dust mites are present all year round causing constant allergy - 'perennial' allergic rhinitis. The excretion from the mites dries out and can be launched into the air when someone walks over a rug, sits down in a chair, or shakes the bed clothes, giving allergic people immediate symptoms.

What are the symptoms of house dust mite allergy? TOP OF PAGE

Hay fever, runny nose, itching, sneezing.
Watering eyes.
Asthma, difficulty in breathing.
Infantile eczema (a skin disease) may get worse.

What makes the symptoms worse? TOP OF PAGE

Air pollution such as tobacco smoke or car fumes.

How does the doctor make the diagnosis? TOP OF PAGE

It is often enough to tell the doctor when, where and how you get the symptoms. Skin tests and various blood tests can be used for confirmation.

Good advice TOP OF PAGE

It is best to do everything possible to avoid hypersensitivity to house dust mites. People who have perennial rhinitis, inflamed mucous membrane of the nose, or are allergic to house dust mites should try to adapt their homes.

Dust mite poo weakens skin (Reuters - Friday, 29 September 2006) TOP OF PAGE

Dust mites and their faeces contain an enzyme that destroys the protective function of the skin, leaving it open to other irritants (Image: USDA)

Dust mites, which infest the cleanest homes and thrive in bedding and carpets, disrupt the protective function of the skin, a study has found.

This leaves it vulnerable to other allergens and irritants in the environment.

House dust mites and their droppings have long been linked to asthma and eczema attacks, and researchers in Japan say they think they know why.

In a paper to be published in the Journal of Investigative Dermatology, the researchers found that mites and their faeces contain an enzyme, which destroys the protective function of the skin, leaving it vulnerable to other irritants.

"People go to hospital only after they develop severe [skin] disease, but little is known as to what happened or what caused it," says Assistant Professor Toshiro Takai of the Atopy Research Centre at the Juntendo University School of Medicine in Tokyo.

"Our study suggests that it may be due to the disruption of the barrier function of the skin [by the dust mite]."

In their experiment, the scientists dabbed hairless mice with a solution containing the mite enzyme and observed that the rodents soon suffered water loss from their skins.

They then dabbed the mice with riboflavin, or vitamin B2, which is accepted in the scientific community as a substitute for allergens and irritants in the environment.

"We observed in the mice transepidermal water loss, which is an indication of disruption of the skin barrier. We also observed the penetration of riboflavin into the skin," Takai says.

Takai says the finding provides an explanation for skin-related allergies in humans and he hopes dermatologists would investigate more closely into the role of the dust mite.

"In a healthy person, the barrier is complete and irritants can't get into the skin. But partial disruption of the barrier facilitates passage of allergens and other irritants," he says.

According to the World Health Organization (WHO), asthma affected 300 million people worldwide in 2005, killing 255,000 of them.

The death figure is expected to increase by 20% in 10 years' time if urgent action if not taken, the WHO says.