You are covered in mites – and most of the time that’s completely normal
You are not alone in your own skin. Millions of microscopic creatures live there too.
Our skin is home to entire ecosystems of microscopic life. Bacteria and fungi get most of the attention, but mites are there too. Among the most common are demodex mites, tiny eight-legged relatives of spiders that live inside hair follicles and pores, especially on the face. Almost all adults carry them.
Despite their reputation, they are not invaders. Scientists often describe them as symbionts, organisms that live alongside us as part of a shared biological system. They feed on skin oils and dead cells, spend most of their lives tucked inside pores and come out at night to move across the skin and mate before laying eggs.
Most people never notice them at all.
In the latest episode of the Strange Health podcast, we explore what these microscopic housemates are actually doing on our bodies and why the idea of them can feel so unsettling. If mites are normal, when do they become a problem?
To find out, we spoke to Alejandra Perotti, professor of invertebrate biology at the University of Reading, who studies the relationship between mites and humans.
As Perotti explains, the presence of mites is not a sign that something has gone wrong. Human skin is not a sterile barrier. It is a habitat. That balance can shift, though. In some people, demodex populations increase dramatically, particularly if the immune system is compromised or the skin barrier is disrupted. This has been linked to conditions such as rosacea and blepharitis, which can cause redness, irritation and inflamed eyelids. Even then, the mites themselves may not be the main driver. The immune response to them, or to the microbes associated with them, may be what produces symptoms.
Other mites live alongside us in different ways. Dust mites, for example, inhabit bedding, clothing and carpets, feeding on fungi that grow on shed skin. They do not bite, but their waste products can trigger allergic reactions in some people, contributing to asthma, eczema and hay fever symptoms.
Then there are mites that cause disease. Scabies is caused by a species that burrows into the skin to lay eggs, triggering intense itching and inflammation. Cases have been rising in parts of the UK and Europe, particularly in places where people live in close contact such as care homes, schools and student accommodation.
Despite its reputation, scabies has nothing to do with cleanliness. It spreads through prolonged skin-to-skin contact and is treatable with prescribed creams and coordinated treatment of close contacts. The stigma attached to it often causes more distress than the condition itself.
Head lice are often grouped into the same conversation, but they are not mites at all. They are insects that spread through head-to-head contact and are common among children, regardless of hygiene.
So why does the idea of mites provoke such a visceral reaction? Partly because they trigger our disgust response, which evolved to help us avoid disease. But that instinct can blur the line between normal biology and genuine medical problems.
The reality is less dramatic. Humans are not solitary organisms but ecosystems. Most of the microscopic life on our skin is either harmless or beneficial. Only a small number of species cause disease, and when they do, the issue is medical rather than moral.
Listen to Strange Health to find out which mites are simply part of everyday biology, which ones cause real problems – and why understanding them matters more than fearing them.
Strange Health is hosted by Katie Edwards and Dan Baumgardt. The executive producer is Gemma Ware, with video and sound editing for this episode by Sikander Khan. Artwork by Alice Mason.
In this episode, Dan and Katie talk about a social media clip via TikTok from prettyspatricia.
Listen to Strange Health via any of the apps listed above, download it directly via our RSS feed or find out how else to listen here. A transcript is available via the Apple Podcasts or Spotify apps.
Katie Edwards is commissioning editor of health and medicine at The Conversation in the UK. Alejandra Perotti has received funding from BBSRC.
Dan Baumgardt does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.