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The main focus of mite control procedures should be the bedroom - this is where we spend approximately 1/3 of our time and is where dust mites thrive. Modifying bedrooms is cost effective and of proven clinical benefit.
Mattresses, comforters and pillows should be covered with mite proof covers or "encasings". These used to be made of rather uncomfortable semi-permeable vinyl fabrics. Nowadays, covers made from comfortable, microfine cotton or breathable synthetic fabrics are available that prevent mites or their allergens from passing through. The important feature of these fabrics is that they have a pore size of 6 microns, which is too small for mites to get through. New mattresses should also be covered with encasings (it takes 3-9 months for mites to colonize a new mattress).
Feather pillows have lower mite allergen levels than synthetic pillows because they are made of more tightly woven fabric. Synthetic pillows should be covered with microfine encasings or washed regularly.
Washing bedding weekly in hot water (130°F) kills mites and gets rid of mite allergens. It is important to wash bedding, even if the mattress is covered. This is especially true for patients with eczema because they shed more skin scales (mite food) into the bed. Ideally, stuffed animals should be removed from the bedroom, but any remaining soft toys, animals or mascots should be washable and washed weekly. Heavy curtains should be replaced with blinds or light cotton drapes and soft furnishings should be replaced with wooden, plastic or vinyl furniture.
Where possible, carpets should be removed from bedrooms, as described above. If the carpet has to stay, it should be treated with acaricide (containing 3-5% benzyl benzoate). These chemicals are nontoxic but need to be applied to carpets once a month to be effective. Vacuum cleaning removes surface dust, but does not dramatically reduce mite numbers. Mites burrow into carpet pile and are difficult to remove.
Mite allergic patients should wear a disposable face mask while vacuum cleaning. Preferably a cleaner with 2-layer microfiltration bags should be used to prevent allergens being dispersed from the vacuum cleaner into the air.
The underlying theme of mite control in bedrooms should be to make the room similar to a "comfortable" hospital room. The same principles should be applied to other parts of the house. Carpets control and use of wooden, vinyl or plastic furnishings should be introduced if practicable.
Other options to consider are the effect of temperature on dust mites. Freezing kills dust mites and it has been shown that applying liquid nitrogen to beds or carpets is effective at killing mites. For most people using liquid nitrogen is impracticable. If you live in Northern states, leaving the mattress out overnight on a cold winters night to freeze it, will kill all the mites. Putting soft toys overnight in the freezer is also effective (wash them afterwards to remove allergen).
Alternatively, dry heat will kill mites. In dry climates, leaving carpets out in the hot sun for a day will kill mites. Another approach is to steam clean carpets, although this procedure has not been widely tested. Steam cleaning could be useful in removing mites and destroying heat sensitive allergens. On the other hand, if the process left the carpets damp, it would favor mite growth. Steam cleaning processes vary from one company to another. At present, we know that "dry" steam-cleaning using a Vaporjet 2400 causes significant (>5 fold) reductions in mite allergen over several weeks. However, "wet" steam-cleaning usually has only short term effects (one to two weeks) before allergen levels recover.
What does not work for mites: Air purifiers, room air cleaners, air ionizers, or air duct cleaning are not effective mite control procedures. Mite allergens are only transiently present in the air and are not found in most air duct systems. Acaricides or chemical sprays are not useful for treating furnishings because they do not penetrate far enough into the upholstery.
The approach here is to reduce animal allergen that accumulates around the home and especially to reduce the airborne allergen. Having a cat or dog in the home means that there will almost always be allergen present in the air, especially if there is more than one pet in the house. Patients who are highly allergic to cats or dogs should seriously consider getting rid of the animals and choosing alternative pets. Such patients include those who experience persistent nasal symptoms, breathlessness, wheezing or asthma, or who have had to visit hospital emergency rooms, following contact with cats or dogs.
Discuss your symptoms with your allergist to see if removing the pet is the best option for you. If you decide to get rid of the pet, it may take several weeks or months to completely get rid of the animal allergen. This is best achieved by vacuuming regularly using a vacuum cleaner, with a high efficiency particulate air (HEPA) filter or a cleaner with 2-layer microfiltration bags. All bedding, carpets and soft furnishings should be washed or cleaned. Walls, floors and other surfaces should be washed with detergents to remove the allergen. Use of a HEPA filter room air cleaner is advisable for 1-2 months after removing the pets.
If you decide to keep the pet, there are several things you can do to reduce allergen exposure (see checklist). Keep the pet outdoors if practicable, remove wall to wall carpets, and use HEPA filter room air cleaners. Washing the cat or dog twice a week with a regular pet shampoo or water will reduce allergen on the pet, and in the air, but this must be done regularly. If washing the animal is not practicable (cats!), wiping the fur daily with a damp cloth may help. Bedding should be washed weekly along with any blankets used by the animals.
What does not work:
Replacing cats with other small furry pets such as rats, mice, rabbits, guinea pigs, hamsters, etc. may work for a short while, but eventually allergies to these pets may develop. Small animals produce allergen in their urine and if you are allergic to these pets it is best to change the bedding and litter in their cages regularly (preferably have someone else do this).
Chinchillas may be an exception to this rule. These animals naturally produce very little urine (their thick coats are designed to prevent water loss). Although chinchillas have been farmed extensively for their fur, there are only one or two reports of chinchilla allergy. So, these animals may be worth a try. Otherwise, the choice of "allergen free" pets is down to rather cold creatures - fish, amphibians, lizards, snakes and reptiles such as iguana. That is, unless you would like to consider pot bellied pigs!
The main approaches to controlling cockroaches are physical methods to reduce cockroach access to the home and the use of insecticides. Food should not be left around the kitchen and all foods scraps and waste should be properly disposed of. Water leaks from faucets, sinks and bath tubs should be repaired. Cracks and crevices that harbor roaches should be filled and caulked.
The most effective insecticides contain hydramethylnon, fipronil or abamectin. These are available in supermarkets and drug stores as bait traps and can be applied as gels by pest control companies. The chemicals are effective at killing roaches, but need to be followed up by thorough cleaning using disinfectants, and cleaners to remove dirt and grease, in order to get rid of the cockroach allergen. Consult your local pest control company or agricultural extension service on how best to control roaches in your own home.
If roaches infest your entire apartment building, it may be difficult to stop them getting into your apartment. Such cases should be referred to the local public health department.
The University of Florida Cooperative Extension Service has an excellent web site which gives detailed instructions on cockroach control. The site features least toxic methods of roach control and how to manage cockroaches in low income housing http://edis.ifas.ufl.edu/IG105.
The Safer Pest Control Project also has great information on integrated pest management.
The main strategy to control indoor mold growth is to reduce the humidity. This is achieved by home repairs to prevent water access into the home and repairing leaking roofs, windows, gutters, drains and water system leaks. Damp or wet carpets should be dried and cleaned. Dehumidifiers can be used in basements and air exhaust fans should be installed in kitchens and bathrooms. Showers, bath tubs, tiles should be cleaned with bleach or other bathroom cleaning agents available in supermarkets. Check any indoor plants for signs of mold and limit the number of house plants.
Reducing allergen levels in the home is an important part of allergy and asthma treatment. It helps to reduce inflammation of the nose and lungs and can reduce the amount of allergy and asthma medications needed to control allergy symptoms. You can create "allergen free" conditions in your home and still live comfortably. This may involve changes to your lifestyle to better accommodate your health care needs and those of your family.
It is important to realize that it may take several weeks or 1-2 months before you notice clinical improvement after beginning an allergen control program. That is the time it takes for the inflammatory processes to return to normal. The amount of time to recover will depend on your level of sensitivity to the allergen and how effectively home allergen levels are reduced.
Be wary about claims made by manufacturers of allergen control products, devices and services, concerning their effectiveness against allergens. Often these products and services have not been extensively tested for their effects on allergens. Mattress covers, vacuum cleaner bags and acaricides have been tested and shown to be effective for controlling for mite and cat allergens. For many other products, this is not the case. Ask the manufacturers, sales people or service providers what their claims are based on. Discuss the best approach to allergen control in your home with your doctor.
Some studies suggest that avoiding allergens in the first few years of life prevents the development of allergies and asthma. Large clinical trials are now being carried out to see if this is correct. If you are allergic and are planning to have children, it is prudent to seek counseling from your doctor, pediatrician or allergist on avoiding indoor allergens and allergenic foods early in life.
Over the next few years, we can expect that more consumer friendly methods of assessing home allergens will be developed. We can also anticipate that knowledge of allergenic proteins will lead to improvements in allergy shots and immunotherapy. While lab based tests for allergens are ideal for researchers, they cannot be used by the consumer.
Indoor Biotechnologies has developed a new type of test that is designed similar to a pregnancy test and measures mite allergen in the home. This rapid test detects mite allergen in 10 minutes - it gives a red line if allergen is present, and the color can be compared with High, Medium and Low indicator lines printed on the test. The test comes together with a simple plastic dust collector to make the dust solution that is applied to the test.
Rapid tests are designed to enable consumers to screen several sites in their homes for allergen levels. The tests should help consumers make rational decisions about whether they have allergens present and whether they need to consider avoidance procedures.
Allergen proteins are now being produced using genetic engineering techniques. While still at the research stage, allergens produced by biotechnology will be used for more precise allergy diagnostic tests (especially blood tests) and for improving allergy shots. Allergens can now be engineered so that they have greatly reduced binding to allergic antibodies. Allergens can also be coupled to other chemicals that shift the immune response from one that causes allergic antibody production to one that does not.
Using either engineered allergens or chemically modified allergens, scientists hope to improve existing allergy vaccines and develop new vaccines that may even prevent the development of allergy. Allergy and asthma are significant public health problems. The economic costs of asthma alone are estimated to be $12 billion per year. Improved environmental control and the prospects of new allergy vaccines could profoundly improve the health of our children and our quality of life.