By Deryn Lee Thompson - Eczema and Allergy Nurse; Lecturer, University of South Australia
Dust mites living in household dust can sometimes cause allergies that significantly lower the quality of life. Some methods are more effective than others in getting rid of them.
When we think of "allergies," we often think of
household dust. However, in reality, those with allergies are often allergic to
the dust mites that thrive in it, not the dust itself.
Belonging to the arachnid family, like ticks and spiders, these tiny creatures measure 0.2 to 0.3 mm (0.008–0.012 inches)—around 50 of them could fit on the head of a pin! They
live for 65 to 100 days, with females laying between 60 and 100 eggs during their lifetime.
Dust mites prefer temperate climates and humidity. They feed on skin cells we shed and on molds, which they digest with enzymes. These enzymes are excreted in their feces around
20 times a day. Over their lifetime, they also shed fragments of their exoskeleton. All these protein fragments can trigger allergic reactions in individuals suffering from allergic rhinitis (commonly called hay fever). These fragments are considered allergens.
What are the symptoms?
When people allergic to dust mites inhale the allergens they release, these allergens infiltrate the mucous membranes of the respiratory system and eyes. The body recognizes and perceives them as a threat, releasing various chemicals, including a molecule called histamine.
This leads to symptoms such as itchy eyes and throat, sneezing, coughing, nasal discharge (runny nose), and postnasal drip (a sensation of mucus in the back of the throat).
People suffering from this allergy often breathe through their mouths, snore, and constantly rub their noses (which can lead to the formation of
a transverse nasal crease, hypo- or hyperpigmented, due to repetitive rubbing—a movement sometimes referred to as the "allergic salute").
They may also suffer from fatigue and have dark under-eye circles, as dust mite allergies
can disrupt sleep quality. This results in decreased concentration levels at work or school and lowers their overall quality of life.
Additionally, in individuals with eczema, protein fragments released by dust mites can penetrate damaged skin barriers. This prompts immune cells in the skin to
release chemicals, escalating irritation. As a result, the skin becomes redder and more painful, particularly in children.
Allergy symptoms are often more pronounced after going to bed and upon waking in the morning. Symptoms persist year-round but may worsen in spring for individuals allergic both to mites and pollen.
How is this allergy diagnosed?
Symptoms of dust mite allergies can last for months or even years before individuals seek medical advice. Yet obtaining a diagnosis is essential for accessing the appropriate treatment. Consulting a healthcare professional also provides information on reducing exposure to allergens.
To determine if a person is allergic, healthcare professionals may order a
blood test. Skin tests (also called prick tests) may also be conducted by allergists. These tests involve
placing droplets of various allergens and control substances (positive and negative controls) on the skin, then pricking through each droplet to introduce a small amount into the skin. After 15 minutes, the reaction is observed. If the person is allergic, the skin will be raised, red, and itchy, similar to a mosquito bite.
How is a dust mite allergy treated?
Once diagnosed, healthcare professionals develop a
medical management plan for allergic rhinitis to alleviate symptoms.
Treatment options often include one or more of the following:
- non-sedating antihistamines (taken daily);
- a corticosteroid-based nasal spray (these sprays are commonly misused, so it is vital to follow the
proper usage guidelines);
- anti-allergy eye drops.
If the patient also has
asthma or eczema worsened by dust mites, the treatment plan will be adapted to account for
the one and
the other.
In severe cases,
allergen immunotherapy may be a long-term option. This approach progressively desensitizes the immune system, so it no longer identifies dust mite proteins as threats.
Immunotherapy involves daily sublingual tablet administration or a series of injections. The injections require monthly visits to the allergist over a period of three years, following an initial phase of weekly injections.
These treatments are
effective but costly (and time-consuming). If you are considering this option, it is important to weigh the pros and cons with your healthcare provider.
How to minimize the impact of dust mite allergies daily
To reduce the amount of allergens in your environment,
several measures can be taken. Here's a non-exhaustive list.
Bedding and pajamas should be washed weekly in hot water. Choose duvets, covers, blankets, and sleepwear that can be washed at 60 °C (140 °F), as this temperature eliminates not only dust and allergens but also kills
mites and their eggs.
If washing at this temperature isn't possible, select dust-proof covers that prevent mites from settling in. These covers should be wiped with a damp cloth every time bed linens are changed.
In terms of furnishing, if possible, opt for blinds and wooden floors instead of curtains or carpets. Avoid plant-based flooring (sisal, seagrass, etc.), fabric sofas, wall hangings, stuffed toys, and other items that can harbor dust.
For cleaning, dust blinds and other surfaces weekly with a damp cloth. When vacuuming, allergy sufferers should wear a mask, as mites may become airborne (better yet, let someone else handle the vacuuming).
Beware of misleading marketing promises
When buying a new mattress, it is initially free of mites. However, mites will begin colonizing it once you start using it. This may tempt consumers to pay for expensive products marketed as "hypoallergenic," "anti-allergy," or "allergen-free."
The issue is that the pore size of these products is often not small enough to block mites, their feces, or the skin cells they feed on. Currently, the only commercial fabric with pores small enough to
meet these claims is MicroTight™ fabric.
Additionally, sprays designed to kill mites require such heavy application to penetrate fabrics that they may leave the materials very damp and with a noticeable odor (and if not properly dried, there's a risk of mold growth).
Finally, claims about certain expensive vacuum cleaners being capable of completely extracting mites lack scientific evidence.