Reducing house-dust mites is key to managing your allergies over the colder months. Allergy New Zealand’s allergy advisor Penny Jorgensen provides tips to decrease them in your home.
The most common allergy symptom is allergic rhinitis and the most common trigger year round is house-dust mites.
These pesky, microscopic arachnids live all over our homes, and leave lots of ‘droppings’. This is the dust we see, and is what causes our allergy symptoms.
House-dust mites thrive in warm (not hot or cold), damp environments. They are difficult to get rid of, particularly in New Zealand’s temperate, humid climate, but it is possible to reduce their numbers, particularly around and on the bed where we are most exposed to them.
Hot wash bedding weekly
ASCIA recommends washing sheets, pillowcases and other bedding weekly in hot water – at or over 60°C. This will both kill house-dust mites and wash away the dust they produce.
Alternatively, if it is not possible to wash in hot water, use a commercial product containing tea tree or eucalyptus oil, formulated to kill dust mites in cold water. Once washing is dry, 10 minutes of hot tumble drying will also kill dust mites.
Use dust-mite covers
It is also recommended to cover the mattress, pillow and duvet with dust-mite-resistant covers. The mattress and duvet covers must be washed every two to three months, and pillow covers at least every six weeks. Follow the manufacturer’s instructions for washing.
If dust-mite covers are not available, wash blankets and non-encased washable duvets every three months in hot water. It is not recommended that you use sheepskins or woollen underlays as they collect dust and are difficult to wash.
Wash soft toys regularly
Soft toys can collect dust and should also be washed regularly in hot water or with eucalyptus oil – or they can be placed in the freezer overnight (although this will not remove the dust itself, just kill the dust mites).
Vacuum carpets weekly
For the house as a whole, including the bedrooms, it helps to replace carpets with hard flooring. If this is not possible, vacuum carpets weekly. Look for a cleaner with a high efficiency particulate air (HEPA) filter and carpet or underlay that has been treated to inhibit mould and dust mites.
Just note that vacuuming actually stirs up dust and increases the amount in the air for up to 20 minutes. If you are the one with the allergy, ask someone else to clean for you.
Dust hard surfaces weekly around the home with a damp or electrostatic cloth. When buying new furniture, choose items made of material that is easy to clean, such as wood, leather, vinyl or rattan, rather than cloth.
Reducing the level of humidity in your home can also discourage house-dust mites. Use a ventilation system, or open windows on dry days to ventilate your house and use fans or vents to remove steam when cooking, showering or using a drier.
A dehumidifier can help, but you need to get the humidity level below 50 per cent to have a significant effect. Good insulation in your home also helps. Avoid using water-cooled air conditioners or unflued gas heaters, as these both release water into the air and can increase indoor dust-mite and mould levels.
Keep using allergy treatments
It is important to maintain your allergy treatment in winter, including intranasal corticosteroid sprays if you are using these as preventers for allergic rhinitis.
Plan to prevent asthma and flu
Allergic rhinitis can also inflame asthma so it is a good idea to prepare for winter by making sure your Asthma Management Plan is up to date, and by getting the flu vaccination from your GP or nurse.
Allergen minimisation Australasian Society of Clinical Immunology and Allergy (ASCIA), 2019
Allergy New Zealand allergy advisor Penny Jorgensen