Introduction to allergen avoidance


Once you are allergic to a substance, the best way to treat it is to avoid what you are allergic to. This will alleviate symptoms if you are able to avoid the allergen. It is important to first identify what you are allergic to, which is best done by skin-prick tests (or RAST if skin-prick tests cannot be performed). Once you have identified your allergens, you can start to think about allergen avoidance. However, it is not always easy to avoid what you are allergic to. The following is a list of tips from the Australasian Society for Clinical Immunology and Allergy on avoiding allergens in your environment.


Ways to remove or avoid common allergens


House dust mite

House dust mite is a common allergen and there is no easy way of removing it. The following tips may help people with allergic disease (such as asthma, eczema and allergic rhinitis) triggered by house dust mite.

Bedding

  • Wash sheets and pillow cases weekly in water hotter than 55 degrees. Alternatively, hot tumble dry items for 10 minutes after they are dry.
  • Cover mattresses, pillows and quilts with dust mite resistant covers. The covers should be washed in hot water every 2 months.
  • Remove sheepskin or woollen underlays.
  • Remove soft toys from the bed or bedroom. Alternatively, wash soft toys in hot water weekly.


Other measures

  • Replace carpeting with hard floors such as timber, tiles, linoleum.
  • Damp dust or use electrostatic clothes to clean surfaces weekly.
  • Vacuum carpets weekly.
  • Reduce indoor humidity levels, for example, avoid evaporative air conditioning systems and unflued gas heaters.
  • Consider Venetian or flat blinds rather than heavy curtains, or use curtains that are easily washed on a regular basis.
  • Consider using house dust mite avoidance measures when building a new home.


Pets

Pets are a cause of allergic reactions in many people, whether it is your own pets or other people’s pets at home or work. In the home environment, cats and dogs are a major source of allergens. There are no breeds of either cats or dogs that are allergen free, as the allergen comes from sweat glands in cats and salivary glands in dogs, and then adhere to the fur when it sheds. Cat allergen can be particularly difficult to remove from houses, and it can remain airborne for many months after the cat is removed. Cat allergen can also be found in places where cats have never lived, including schools and offices, where it is carried in on clothing by people who have been in contact with cats. Cat allergen has even been found in Antarctica, even though cats have never lived there! The most effective method of allergen avoidance for people who are allergic to pets is removal of the animal.
This can be a difficult decision to make, however a person’s health is very important, especially when it is a child who is allergic to a pet. It is important that discussion about removal of an animal does not take place in front of the child, as they may suffer feelings of guilt. Dogs, guinea pigs, mice and rabbits are not as allergenic as cats and can be more easily kept outside, but removal of the animal may still be required if symptoms are severe. The effectiveness of measures such as keeping pets out of bedrooms and living areas, washing animals frequently and using HEPA filters in vacuum cleaners remains uncertain. Horse allergy is a particularly serious form of allergy, which can cause severe reactions even in small amounts, such as a small amount of animal hair on clothes of a person who lives in the same house as someone allergic to horses.

Mould

Mould is commonly found in bathrooms, refrigerators and places with little air circulation such as walk-in and built-in robes. It can be identified as mould, mildew or a typical musty smell. If tests have shown an allergy to mould, the following steps may be helpful:

  • Remove visible mould by cleaning with bleach or other mould reduction cleaners.
  • Ensure adequate natural ventilation such as the use of extractor fans, especially in bathrooms.
  • Seal leaks in bathrooms and roofs.
  • Clear overflowing gutters and vents under the floor.
  • Remove indoor pot plants (which promote the growth of mould).
  • Dry or remove wet carpets.
  • Avoid garden compost or mulch if possible, or wear a mask.


Pollen

The grass pollen season peaks between September and December in Australia, with the majority of pollen released between 6AM and midday. Thunderstorms can cause bursts of increased pollen counts, when starch granules are released from pollen that are small enough to breathe in, triggering asthma ‘epidemics’. Pollen can be blown for long distances on windy days, however most pollen is deposited within a short distance of the source. The highest pollen counts occur on calm, hot, sunny days in November and December. Sources of pollen are usually grasses or trees that are not flowering. While some people may notice that their hayfever always gets worse when a certain flowering plant is in bloom, these plants are unlikely to be the cause of the symptoms, as there is little airborne pollen produced by flowering plants. Avoiding pollen can be difficult, but the following tips may be useful for patients allergic to pollens:

  • Remain indoors during the pollen season, on windy days or after thunderstorms.
  • Avoid activities that increase exposure to pollen, such as mowing the grass.
  • Shower after activities where there is high exposure to pollen.
  • Use recirculated air in the car when pollen levels are high.
  • Avoid hanging sheets and clothes outside when pollen levels are high, as the pollen will adhere to the sheets and clothes and will be brought inside. Consider using a clothes dryer when pollen levels are high.

 

References

  1. ASCIA Education Resources. Patient Information Brochure: Allergen Avoidance. 2005. Australasian Society for Clinical Immunology and Allergy. Available at: http://www.allergy.org.au/aer/infobulletins/allergen_avoidance.htm.
  2. ASCIA Education Resources. Patient Information Brochure: Aeroallergen Avoidance: is it worthwhile? 2005. Australasian Society for Clinical Immunology and Allergy. Available at: http://www.allergy.org.au/aer/infobulletins/Aeroallergen_Avoidance.htm.