WHAT DOES A DUST MITE LOOK LIKE?
The house dust mite looks like an arachnid and their relations include ticks and spiders (as well as crab, shrimp and lobster). They can only be viewed under a microscope. They are up to 0.5mm long and live for about 2 to 4 months. Their favourite food is skin scales. Dust mites can’t drink so survive on absorbing moisture from the environment through glands at the base of their front legs. That’s why in dry climates, dust mites are almost nowhere to be found even in dusty spaces and conversely beds and couches form popular breeding locations.
In most climates, mite populations increase as humidity increases. Experts suspect that a correlation exists between asthma rates and dust mite population growth. House dust mite allergy is the most commonly encountered dust-related allergy. It is the leading cause of perennial allergic rhinitis (persistent hay fever), and a primary trigger for asthma exacerbation, affecting up to 85% of asthmatics (Thomas et al., 2010).
The problem with dust mites is that their faecal matter (which is a lot) is a major source of powerful allergens. The tiny pellets are able to become airborne and when inhaled get deep into the lungs and cause an asthma attack.
DUST MITE ALLERGY MANAGEMENT
The most important step in allergy management is correctly identifying the cause.
Once ascertained that a dust mite allergy is the cause of the problem, avoiding exposure to dust mites is the best strategy. While you can't completely eliminate dust mites from your home, you can significantly reduce their number. It need not be as difficult as it sounds.
The first room to tackle is the bedroom and in particular the bedding, where we spend the greatest number of consecutive hours. Use these suggestions which have been sourced from allergy experts across the world including Australia, United Kingdom and United States:
A combination of the following five measures is recommended
- Use allergen-proof bed covers for mattresses, quilts and pillows. Wash according to manufacturers specifications.
- Wash bedding weekly. Wash sheets, blankets, pillowcases and quilt covers in water that is at least 55oC or preferably hotter. Hot tumble dry bed linen for at least 10-20 minutes to kill any remaining dust mites. Dry cleaning is not as effective as it will kill house dust mites but won't remove the allergen they produce.
- Remove sheep skins & woollen underlays from the bed and bedroom.
- Don't make your bed in the morning - Turn covers back to 'air' the bed to allow moisture from your body to dry. Reducing moisture makes it difficult for dust mites to live as they rely on it to survive.
- Soft toys. Remove soft toys from the bed and bedroom. If keeping soft toys buy washable ones. Wash them weekly at minimum 55°C if possible; otherwise place them in a plastic bag in the freezer for 24 hours weekly. The freezer will kill the dust mites, but won’t remove the allergens.
Other measures can apply to bedrooms as well as other rooms in the house:
- Remove dust mite habitats. Carpets and rugs (where practical) should be removed from a bedroom. Hard floors such as wood, tiles, linoleum or vinyl are preferable. Consider replacing soft furnishings in the bedrooms (or other rooms) such as upholstered furniture, non-washable curtains. Leather or vinyl furniture could be used as an alternative to cloth. Venetian blinds or flat blinds are easier to clean than heavy curtains. Other options may include washable curtains or external shutters.
- Dust regularly: Use a damp or electrostatic cloth rather than dry materials to clean up dust.
- Vacuum regularly. Use a vacuum cleaner with a good filter (double-layered microfilter bag or high-efficiency particulate air (HEPA) filter) that removes the mite and prevents small particles coming out through the vacuum exhaust. If your allergies are severe, leave the area being vacuumed while someone else does the work. Stay out of the vacuumed room for about 20 minutes prior to re-entry.
- Ventilate rooms (especially bedrooms and clothes dryer areas) by opening doors and window for around 15 minutes per day if possible.
- Control Indoor Temperature. High temperatures are ideal for dust mites to multiply. Keep a moderate temperature 18-20°C throughout the year, especially Summer. An air conditioner can help keep humidity low, however avoid using evaporative coolers as these increase moisture content in the air. Some air-conditioners have filters to reduce allergens. Be sure to change them regularly in accordance with the manufacturer’s specifications. Drying washing on the heater is not recommended nor are un-flued gas heaters.
- Remove clutter as it collects dust.