Skin mite: Does demodecosis need to be treated
Who is Demodex and should it live on our skin?
In Russian patients with acne, rosacea and seborrheic dermatitis are often sent to do Demodex mite tests, considering it the cause of rashes. In the Runet there are several dozen scientific articles and even dissertations on demodecosis, a disease that is provoked by these microorganisms. I try to understand how these mites appear and why in Russia people are treated from these parasites, although Western experts consider this impractical.
Who is Demodex
Demodex mites, the Demodex folliculorum and Demodex brevis species, live on the skin of most people, it is part of our microbiota, one of the millions of microorganisms on the epidermis surface. The microbiota composition may vary from person to person. This is influenced by what we eat, where we live, and hundreds of other factors — so not everyone has this mite.
Demodex lives in the hair follicle mouths and in the sebaceous and meibomian gland ducts. The mite size is less than 0.5 mm, and you can only see it under a microscope. Mites eat our sebum. If little sebum is produced, then they live in hungry, they do not multiply too actively and do not clog the ducts in which they live.
In 2014, Daniel J. Fergus and Megan Thommes from the University of North Carolina examined skin samples to see if there was a link between the Demodex mite and the development of skin diseases. The study results show that 100% of the participants had one of two mite types on their skin: Demodex folliculorum or Demodex brevis. Some had both types at once. However, the study participants were not diagnosed to have skin diseases. No external signs, such as redness, rashes, itching were also observed. In 2015, scientists from the Irish national dermatological research Institute confirmed the conclusions of colleagues made a year earlier: Demodex mites live on the skin of most people and this is normal.
When there are too many mites
Scientists refer Demodex to conditionally pathogenic parasites. This means that mites are natural inhabitants of our body, their presence on human skin is normal. The problem occurs when there are too many of them. They actively multiply and cause disease only when the environment in which they live changes. This happens when the microbiota composition changes, the skin barrier functions deteriorate, its pH changes, or the protective function of the immune system sharply decreases. Patients after chemotherapy, with weakened immune systems, skin infections, dermatitis or rosacea, or HIV infected people are most often at risk.
"When the Demodex has a favorable environment, it actively reproduces. There are a lot of them, they block the hair follicle or sebaceous duct, clog it and provoke a rupture of the follicle. Also mites, their waste or the bacteria they carry can cause an inflammatory or allergic reaction. Elmira Gesheva, candidate of medical Sciences, dermatologist at the European medical center explains. As a result, the patient has a rash, itching, and redness. But the root cause of rashes is not a mite. Its activity is the result of some changes in the human body. You need to start treatment by searching for them."
Why demodecosis is treated differently
In Russia, there is a tendency to "heal": patients are treated for colds, remove benign tumors, prescribe useless and expensive dietary supplements or homeopathy. And in the case of Demodex, people are frightened that if they do not drink a course of antibiotics and do not exterminate mites , this will lead to dermatitis, rosacea and other skin diseases. But modern research shows that this is not the cause and other mechanisms lead to the formation of these diseases.
Western experts do not consider it appropriate to fight Demodex "just in case", largely because the role of this microorganism is studied too little. For example, some studies have found a statistically significant connection between Demodex infection and rosacea. Others suggest that rosacea is caused by other causes, while mites are just comfortable to live in a changed environment.
Does it cause skin diseases
The presence of this microorganism in the test results is normal. This does not mean that it is active or affects the skin condition. Doctors often make a mistake: they treat patients from a rampant mite, instead of understanding why it began to actively multiply and contribute to inflammatory reactions. Confusion occurs because the external manifestations of demodecosis (and it still exists, more about it is below) often look like symptoms of other skin diseases: folliculitis, acne, rosacea or seborrheic dermatitis.
"Unfortunately, in Russian practice, it often happens like this: a patient with acne comes to see a dermatologist, the doctor sees pustular rashes on the face and offers to pass tests for a mite. According to the test results, the tick is detected — the patient is diagnosed with "demodecosis" and prescribed antibiotics. The patient undergoes the course of treatment and, of course, feels better as he took medication. However, since it was not the root cause that was treated, for example acne, but demodecosis, the mites' population returns to normal after a while. And the patient again "treats" mites, the dermatologist explains.
How to treat and when to go to the doctor
It is still not clear what role Demodex plays in skin diseases: it strengthens, prevents them from being cured, or does not affect anything at all. Nevertheless, true demodecosis still exists, although it is much less common than it is diagnosed in Russia. The diagnosis in this case sounds like "another acariasis", and typical foci appear on the skin, often without previous acne. It is important that this disease occurs in severe immunodeficiency — for example, after chemotherapy, AIDS, or terminal kidney failure. For diagnostics, the material is studied under a microscope, which is obtained either by scraping or during a biopsy. It is treated with local medications — salicylic acid, antibiotics, retinoids for skin application and sometimes prescribed antibiotics or retinoids for oral intake.