Demodex folliculorum (DF) is a common skin disease affecting millions of people worldwide. It causes red, itchy lesions that appear on the face, arms, legs and trunk. These lesions may be itchy or painful. They often resemble spider webs or mold growths. They can affect any part of the body but tend to occur most commonly on the palms of hands and soles of feet.
The disease is caused by a single species of bacteria called Demodex folliculorum. There are two types of D.
folliculorum: Fusarium venenatum and Pthirus pubis. Both types cause similar symptoms, which include itchy, scaly patches on the skin. However, one type appears to be more common than the other.
In general, the more active the infection, the larger and denser its patches become. Sometimes they are very large with many small bumps.
Other times they are smaller and less dense. Some patches may even look like little flecks of dirt or dust. Occasionally, some patches will not have any visible bumps at all; these are known as “crypt” spots because there is no obvious source of infection on them.
Both forms of D.folliculorum are species of Demodex.
The most common is D.folliculorum. It is a microscopic mite that lives in the hair follicles of mammals, including humans. While it is normal for everyone to have some D.folliculorum living on their skin, they are mostly harmless unless a person’s immune system is weak.
The disease is contagious but only spreads from an infected person to someone who has direct skin-to-skin contact. It cannot spread through clothing, bed sheets, or other surfaces.
It may also take several days to show symptoms after being exposed to the bacteria.
The disease is most common in children under the age of 10 and older people over the age of 60. However, no age group is safe from infection.
The reason for the higher rate of infection in children and older people is unknown. The disease can appear in people of any age.
There are several schools of thought concerning the cause of demodicosis. Some believe that it is caused by a dysfunction of the immune system, while others believe that there is direct involvement by external factors such as bacteria or mites.
The symptoms are non-specific, which means that they could point to a wide variety of skin disorders. In many cases, the symptoms can also be caused by other factors that do not involve the immune system or skin disorders at all.
For this reason, it is very difficult to diagnose demodicosis before taking a biopsy of the skin.
Demodicosis is typically diagnosed through a physical examination and a series of questions about a person’s medical history. A doctor may also test a small sample of skin, using a microscope to look for mites and their eggs.