The Tiny Invaders in Your Home: Dust Mites

By Jane Yang 楊靜悠

When it comes to allergies, many people think of pollen or pet dander. But did you know that one of the most common culprits might be lurking in the dust? Meet the dust mite, a tiny creature that can wreak havoc on your immune system. In this article, we will answer some common questions about dust mites, why they are so problematic, and how you can reduce their presence in your home.

What Are Dust Mites?

Dust mites are microscopic creatures with a body size as small as a quarter of a millimeter that you can hardly see them without a microscope [1, 2].

Unlike insects, which have six legs, adult dust mites are close relatives to spiders and ticks, so they have eight legs [2]. Another key difference between insects and arachnids also lies in their anatomy. Insects have three main body segments – head, thorax and abdomen, whereas arachnids only have two – cephalothorax and abdomen (footnote 1) [3].

While dust mites don’t spin webs like spiders or suck blood like ticks, they are just as persistent. These tiny creatures thrive in warm, humid environments. A relative humidity of 75% is ideal for their proliferation, at which they can absorb sufficient water vapor with their specialized glands, the supracoxal glands, above the first pair of legs [2, 4]. The hypertonic sodium and potassium chloride solution secreted by the glands facilitates water absorption through osmosis. This body feature enables dust mites to survive for 65–100 days and lay 30–80 eggs during their lifetime at room temperature. At a higher temperature of 30°C, dust mites mature into adult and start reproducing much faster (from 35 to 17.5 days for Dermatophagoides farinae) [2, 5], making them a tough opponent in the battle for a clean home.

Dust mites feed on dead skin cells shed by humans and pets. This means they love to settle into places like bedding, mattresses, carpets, curtains, and upholstered furniture [1, 2]. If you’ve been sneezing or itching at home, dust mites might be the hidden cause.

How Can Dust Mites Cause Allergies?

Despite their tiny size, dust mites can cause massive problems for allergy sufferers. The trouble comes from certain proteins found in their feces, urine and dead bodies [6]. Inhaling these proteins, known as allergens, may trigger an overreaction of the immune system in some people. In these cases, your immune system mistakenly identifies them as invaders and sets off an allergic reaction, inducing the following typical allergy symptoms [1, 6]: sneezing, runny or stuffy nose, watery eyes, itchy skin or rashes, and coughing. In severe cases, it can trigger asthma attacks.

The allergens are microscopic, so they can easily become airborne when you vacuum, sit on furniture, or make your bed, which makes them hard to avoid. However, there are still methods to reduce the threat of dust mites.

How Can You Reduce the Level of Dust Mites?

1) Keep humidity low

Dust mites thrive in warm, humid environments. Using a dehumidifier or air conditioner to keep indoor humidity below 50% makes them harder to survive and reproduce [6] because the water balance can’t be maintained at the supracoxal glands, so adult dust mites will dehydrate and eventually die [2].

2) Wash bedding frequently

Since dust mites love to live in your bedding, make it a habit to wash your sheets, pillowcases, and blankets in hot water every week. A water temperature higher than 60°C can effectively kill dust mites and their eggs [1, 2].

3) Dust regularly

Dust hard surfaces regularly with a damp cloth to avoid stirring allergens into the air [6].

4) Minimize dust-collecting surfaces

Reduce clutter and avoid heavy fabrics like curtains or upholstered furniture [1, 6]. Opt for washable shades and hard flooring, such as wood or tile instead of carpets. If this is not possible, vacuum your carpets and rugs by using a vacuum cleaner with a HEPA (high efficiency particulate air) filter, which can trap dust mites and their allergens [6].

Remember, while you can’t see dust mites, you can certainly feel their effects — and now, you know how to fight back!

1. Cephalothorax: The prefix “cephalo-” means head in Latin, so “cephalothorax” refers to the fused head and thorax of arachnids.

References

[1] Asthma and Allergy Foundation of America. (2015, October). Dust Mite Allergy. https://aafa.org/allergies/types-of-allergies/insect-allergy/dust-mite-allergy/

[2] Miller, J. D. (2019). The Role of Dust Mites in Allergy. Clinical Reviews in Allergy & Immunology, 57, 312–329. https://doi.org/10.1007/s12016-018-8693-0

[3] National Park Service, U.S. Department of the Interior. (2021, May 9). Insects and Arachnids. https://www.nps.gov/ocmu/learn/nature/insects.htm

[4] Arlian, L. G., & Platts-Mills, T. A. E. (2001). The biology of dust mites and the remediation of mite allergens in allergic disease. Journal of allergy and clinical immunology, 107(3 Suppl), S406–S413. https://doi.org/10.1067/mai.2001.113670

[5] Denmark, H. A., & Cromroy, H. L. (2020, June). house dust mites - Dermatophagoides spp. Institute of Food and Agricultural Sciences, University of Florida. https://entnemdept.ufl.edu/creatures/urban/house_dust_mite.htm

[6] American Lung Association. (2024, November 5). Dust mites. https://www.lung.org/clean-air/indoor-air/indoor-air-pollutants/dust-mites