At any given moment, a microscopic world exists on your skin, with countless creatures contributing to the balance of your microbiome — the community of tiny living creatures that inhabit your skin. Among these are Demodex mites, which quietly live, crawl, and reproduce in the pores of your face. While they might look peculiar under a microscope, these mites are a natural part of your skin’s ecosystem, playing a key role in maintaining its health — unless their population grows out of control.

What are Demodex mites?

“Demodex” comes from the Greek words for ‘fat’ and ‘boring worm,’ though these mites are not worms at all — they are microscopic arthropods, relatives of ticks and spiders. They are too small to see with the naked eye and their long, semi-transparent bodies measure about 0.3 millimetres, meaning it would take five adult Demodex to stretch across the head of a pin. With eight legs and scaly bodies, they cling to hair follicles, where they feast on skin cells and oil, comfortably setting up camp. 

There are two main species of Demodex found in every human: Demodex folliculorum (D. folliculorum) and Demodex brevis (D. brevis). The more common of the two, D. folliculorum typically inhabits the facial area, particularly around eyelashes, where it feeds on skin cells and oil. 

In contrast, D. brevis is less common but affects larger body areas. It resides near oil glands in hair follicles, consuming sebum — the oily substance produced by sebaceous glands to keep skin moisturized. These mites are most numerous in the oilier areas of the face, such as the nose, forehead, and chin. 

Demodex mites live for about two weeks, decomposing inside your hair follicles after they die. They spend most of their time within your pores, crawling out only at night to mate and lay eggs in your follicles. Interestingly, you aren’t born with these mites — they are usually passed to you through direct skin-to-skin contact with the people you live with. So, thank your family for sharing them with you!

Why do we need them? 

Although these tiny mites might give you the creepy-crawlies, you won’t be able to evict them with a good scrub. Living deep inside your pores, your Demodex companions are nearly impossible to eliminate.  

Despite their unsettling nature, Demodex mites play an important role in your skin’s microbiome. In small populations, they help maintain a healthy balance by consuming excess oil and dead skin cells. This process supports skin turnover — the natural shedding of old skin cells. As newer cells push to the surface, older ones gradually harden and die off within four weeks. 

While we naturally lose these cells through rubbing or washing, our Demodex companions lend a hand by removing them for us. By breaking down excess oil, they also help prevent clogged pores, which can lead to acne. When kept in check by the immune system, Demodex mites are essentially harmless. Problems arise, however, when their population grows too large, contributing to several skin conditions. 

Can Demodex hurt us?

While a certain amount of Demodex mites are generally harmless, an overpopulation can contribute to various skin disorders. One common condition linked to excess Demodex is rosacea, which causes facial redness and inflammation. Studies have found higher numbers of these mites in the same areas affected by rosacea, but it’s still unclear whether the mites cause the condition or if rosacea creates an environment that encourages mite growth. Often, rosacea is a lifelong condition with no known cure. 

In addition to rosacea, an overpopulation of Demodex mites can lead to demodicosis or Demodex folliculitis — a condition more commonly diagnosed in seniors or immunocompromised individuals, whose weakened immune systems struggle to manage infections. This condition causes symptoms like redness, itching, and sensitivity, particularly on the face. Although rare, it can result in significant discomfort and is often linked to declining immune function. For most people, however, Demodex mites remain harmless and are not a cause for concern.

Protecting our skin during winter

Our skin faces unique challenges as the typical Canadian winter brings colder, drier weather. The drop in humidity and exposure to cold air can compromise the skin’s moisture barrier, causing dryness and irritation. Winter can be especially troublesome for individuals with rosacea or other Demodex-related skin conditions. Cold temperatures often trigger flare-ups, particularly with strenuous activities like skiing or shovelling snow. 

A National Rosacea Society survey suggested that the harsh conditions of winter can worsen rosacea symptoms without proper precautions. Cold air and wind tend to severely dry out rosacea-prone skin, while the added stress of holiday activities can further aggravate skin health.

To address this, winter skincare should focus on maintaining a healthy balance of oils and moisture. For those with rosacea or Demodex-related conditions, avoiding over-cleansing or using harsh products that strip the skin’s natural oils is important. If the Demodex population becomes excessive, a dermatologist may recommend treatments to reduce their numbers.  

Though Demodex mites are often seen as unwelcome guests, they play an essential role in the skin’s ecosystem. By maintaining a healthy balance of oils and moisture, and seeking professional guidance when necessary, you can help ensure that your skin remains in harmony with the microscopic world living on it.