A particular mite may play a role in contributing to rosacea flare-ups. Studies have shown that these mites were significantly more numerous in the skin samples of people with rosacea than of people without. Although this mite is not a cause of rosacea, an allergic-like reaction to these mites or to the bacteria they harbor may trigger an inflammatory response that leads to the condition.
Although rosacea research scientists have been speculating about the rosacea causes for more than a century, none of them have been definitively proven. Most experts believe that rosacea can be provoked by several different factors, some of which may work together to cause it. One of these potential causes is a microscopic mite.
This mite goes by the name of Demodex folliculorum. It is a normal resident in human skin, living in hair follicles, where it dines on cast-off skin cells. These mites have been retrieved from almost every area of human skin, but they seem to prefer the skin on the face.
Two recent studies revealed that the mites were significantly more numerous in facial skin samples of people with rosacea than of people without the condition. In addition, the mite population peaked on the skin samples of these people in the spring, when rosacea tends to flare up.
Other studies show that people with steroid-induced rosacea also had a higher mite population on their faces. This population dropped when the rosacea subsided after treatment with an ointment that kills mites (see Steroid Rosacea).
Although these findings do not prove that the skin mite causes rosacea, they do suggest that Demodex folliculorum might play a role in fostering the disorder. The mites may provoke rosacea by clogging skin follicles, which, in turn, might trigger an inflammatory response.
Rosacea may also be triggered by an allergic-like reaction to these skin mites or to the bacteria they harbor. These mites could then multiply excessively or penetrate more deeply into the skin, triggering an inflammatory response in the form of pimples.