Could you be allergic to dust mites?

For the squeamish among us, dust mites are not a pleasant thought. They’re tiny bugs that feed off discarded human skin scales, house dust, and other microscopic food sources like pollen and fungal spores, and are a common allergen.

Find out what you can do about these small yet powerful mites.

Dust mites are tiny organisms belonging to the same family as spiders that live side-by-side humans, they don’t bite skin on humans but feed off our discarded skin. While most people wont be sensitive in the general population if you have asthma, hay fever and eczema you are more likely to have allergic symptoms trigered by dust mites and what they leave behind. They shed their droppings and skin and are so tiny they can’t be seen without a microscope.

One of a few common environmental allergens, dust mites - along with mould, pollens and animals - love hot and humid areas, so are more common in coastal areas and are often found in soft furnishings like clothes, bed linen, couches, carpets and soft toys.

Associate Professor Janet Rimmer, an allergist, respiratory specialist and researcher at the Woolcock Institute, says dust mite allergies and their effects are under recognised.

“It impacts on quality of life,” she says. “There’s quite a lot of data now saying there’s a reduced ability to work effectively, to do exams effectively, sleep quality is impaired, and there’s also some data showing there’s increased risk of car accidents in people with severe allergic rhinitis. So, it has a lot of flow-on effects in terms of quality of life, not just in the symptoms that people recognise.”

Dust mite allergy symptoms

According to Better Health Victoria, symptoms of dust mite allergy include:

• wheezing or coughing
• breathlessness
• a tight feeling in the chest
• a runny or itchy nose
• itchy eyes or skin
• skin rashes.

Getting rid of dust mites at home

While it’s not possible to get rid of dust mites completely, you can reduce your exposure to dust mites at home by:

• using dust mite mattress, pillow and quilt covers
• regularly washing bedding and soft toys in hot water (more than 55°C) or with laundry products containing eucalyptus or tea tree oils
• avoiding woollen bedding
• keeping humidity at bay with good ventilation and a dehumidifier or air conditioner
• vacuuming with a HEPA filter weekly or, even better, asking someone else to do it so you can be out of the room while the dust mite allergens are airborne
• keeping pets outside the house
• drying clothes and bedding in sunlight
• considering replacing carpets with wood or tiled floors
• cleaning blinds and curtains regularly
• washing clothing that’s been in storage for some time.

However, Assoc Prof Rimmer says minimising techniques aren’t always effective for everybody and may have different results for everyone. “The analysis really doesn’t support dust mite avoidance,” she says. “That’s because we can’t reduce the triggers low enough for some people. It works for some people, but I can’t pick who those people are going to be. In my practice, I give people all the information [on reducing exposure] that I can, but I certainly don’t say to them this is definitely going to be the answer.”

There are companies that claim chemical sprays, air filters and negative ion generators can reduce dust mites, but there’s little evidence to back this up.

Who is affected by dust mite allergy?

Assoc Prof Rimmer says dust mite allergy is common in Australia, and many people are likely to be unaware they’re sensitive to them. And even among those who have been diagnosed, it can be difficult to pinpoint trigger situations.

“The activities associated with dust mite exposure are not clearly understood,” she says. “And I think it’s true to say that scientifically, we don’t really understand how exposure occurs.”

A dust mite allergy can affect anyone, although most have a genetic disposition. Having two parents who are allergic raises your chances of an allergic disease by “up to 80%”, she says.

People sensitive to dust mites are more likely to have a worsening of symptoms in March and April, following the humid summer months which increase dust mite populations, and also when the cold weather sets in.

“The issue in winter is that people either bring out bedding or clothing which has been stored and which may have fairly high dust mite content inside them, so that may trigger them at that time,” explains Assoc Prof Rimmer. “But the rest of the year, the levels are probably fairly constant.”

Our warm, humid climate in Australia makes dust mite levels fairly high, especially along the east coast. “You’ll get a winter kill-off in dust mites in places in Europe and America, but we don't get that here,” she says.

How is dust mite allergy treated?

First, you’ll need to do allergy testing to figure out if dust mites are triggering your symptoms. Your GP can refer you to get tested. Once diagnosed you can then start treatment or medication, depending on your symptoms.

Some people are treated with immunotherapy, which gradually exposes you to dust mite allergens to train your immune system to be less sensitive to them. Symptoms can improve after three months but the recommended course of treatment is three years, Assoc Prof Rimmer says. Many immunotherapies approved by the TGA (Australia’s regulatory body) are covered by HCF so check with your doctor to find out if you’re covered for the immunotherapy they prescribe.

“If you’re in the more severe category, then I think going down the track of desensitisation is a very appropriate way forward,” she explains.

Words by Trudie McConnochie
First published June 2021