The most common allergic triggers of asthma are house dust mites, pollen, pets and mould. Reducing exposure to your asthma and allergy triggers may improve your asthma control. It can help reduce the amount of medication you need and how often you need to take it.

• House dust mites
• Pollen 
• Pets 
• Mould 

House dust mites

House dust mites are microscopic creatures that feed off human skin scales. They are a very common cause of allergies in humid parts of Australia.

Reducing exposure to house dust mites involves:

• Killing house dust mites
• Removing the allergen they produce
• Reducing areas where they can live and breed

Steps to reduce exposure should focus on your bedroom, as the greatest exposure to house dust mites is from your bed. Some useful measures are:

• Cover your mattress, quilt and pillow with dust mite-resistant cases
• Wash sheets and pillow cases weekly in water hotter than 55°C
• Remove untreated sheepskin or woollen underlays
• Remove soft toys from the bedroom, or wash them weekly in water hotter than 55°C

Some other measures that may be helpful are:

• Use a damp or electrostatic cloth to dust hard surfaces (including hard floors) weekly
• Ask someone else to do the vacuuming while you leave the room. Vacuuming increases the amount of dust mite allergen in the air for up to 20 minutes. High efficiency particulate air (HEPA) filter vacuum cleaners may remove more allergens than other vacuum cleaners, but they still increase the amount of allergen in the air during use
• Reduce indoor humidity by having a dry, wellventilated home with adequate floor and wall insulation and no evaporative coolers or unflued gas heaters
• Clean window coverings (blinds and curtains) regularly
• Consider house dust mite avoidance measures when building or renovating your home

Pollen

Many Australians are allergic to windborne pollen from grasses, weeds and trees. This pollen can blow into your nose and eyes, triggering asthma and/or hay fever. Completely avoiding pollen can be difficult during the pollen season, but the following steps may help reduce your exposure:

• Avoid going outdoors on days with high pollen counts, on windy days or after thunderstorms • Use re-circulated air in the car when pollen levels are high
• Use your prescribed medications before going outdoors when pollen cannot be avoided, and keep your asthma reliever with you
• Shower or wash your face and hands thoroughly after activities where you have high exposure to pollen
• Wear a facemask in special situations, such as when driving a tractor during harvest
• Consider low-allergen plants pollinated by birds or insects when landscaping your garden 

Pets

Cats, dogs, guinea pigs, rabbits, horses, mice and rats can all cause asthma or allergies in some people. The most effective way to reduce your exposure to pet allergens is to avoid those animals. If you know you are allergic to certain pets, ask friends to keep them outside when you visit.

If you are allergic to your pet, but you want to continue living in the same household, some steps that might be helpful are:

• Always wash your hands after touching your pet
• Keep your pet outside most or all of the time and never let it into the bedroom
• After resettling your pet outside, clean the house thoroughly to remove sticky allergens left behind
• Ask someone else to groom your pet regularly
• Do not wash your pet more than your vet recommends.

Even after taking these steps, it may take months before allergen levels are reduced, particularly if your pet is a cat. Make sure you take your prescribed medications to help you keep your asthma and/or allergy symptoms under control. 

Mould

Living in a home that is damp or has visible mould, mildew or a musty smell can cause problems for people allergic to mould. Mould is commonly found in bathrooms, fridges and in places with little air circulation such as walk-in and built-in wardrobes, and in bedrooms with ensuite bathrooms.

If you are allergic to mould, if may be helpful for you to:

• Remove visible mould by cleaning with bleach or other mould reduction cleaners
• Ensure adequate ventilation, including the use of extractor fans
• Seal leaks in bathrooms and roofs
• Clear overflowing gutters and blocked underfloor vents
• Remove indoor pot plants (which promote mould growth)
• Avoid working with garden compost or mulch, or wear a facemask if you do

This information was adapted in part from Patient Information: Allergen Avoidance, Australasian Society of Clinical Immunology and Allergy. 

Want to know more?

If you would like to view copies of our useful guides, find out more information on managing your conditions or get tips on how to avoid common asthma and allergy triggers, please go to Living with Asthma & Allergy. 

Medical Disclaimer
Although all care has been taken, these publications are a general guide only and are not intended to be a substitute for individual medical advice or treatment. Any questions regarding a medical diagnosis or treatment should be directed to a medical practitioner. The National Asthma Council Australia expressly disclaims all responsibility (including for negligence) for any loss, damage or personal injury resulting from reliance on the information contained herein.

Content Updated 20 December 2009