(RxWiki News) What makes us rosy in the cheeks isn't always light and merry. This is true particularly among rosacea patients inflamed around their visage.
Researchers may have found the cause of rosacea: bacteria from mites that live in the skin, according to a new literary review of previous studies.
"Don't fear what's in your skin."
The review, led by Kevin Kavanagh, PhD, of the National University of Ireland, examined several studies on rosacea and its causes.
They found that the bacterium Bacillus oleronius produces molecules that cause an immune reaction in rosacea patients.
The bacterium is found in Demodex folliculorum, a harmless mite that usually lives along the hair follicles of the face.
They increase in number as people age and among those with skin damage. And they are more common among rosacea patients compared to normal individuals.
The extent of their population is between 20 and 80 percent of individuals and reaches 100 percent among the elderly.
When the mites breach the skin, their antigens cause the immune system to react. The body then sends cells to attack the mites, causing inflammation in the face.
Rosacea normally affects fair-skinned ladies although the men who are affected tend to develop lesions in the skin.
Researchers say that the human skin may be inhabited by two species of the mites, both worm-like in shape. Their main food source is the skin cells, but their role is not yet known.
Previous studies have shown that patients with varying types of rosacea react to molecules created by this bacterium.
In rosacea's early stages, no visible inflammation is observed, probably because of an unidentified genetic defect among the 3 percent of rosacea patients in the US.
Then in the later, more inflamed stages of rosacea, the immune system is over stimulated, bringing more blood flow to the face and increasing temperature.
This creates a favorable feeding ground for different microorganisms, including the mites.
These mites may block hair follicles, secrete digestive enzymes and damage the skin or trigger the immune system to react.
"The bacteria live in the digestive tracts of Demodex mites found on the face, in a mutually beneficial relationship," Dr. Kavanagh said in a press release.
"When the mites die, the bacteria are released and leak into surrounding skin tissues - triggering tissue degradation and inflammation."
The author is a recipient of a Hume Scholarship from NUI Maynooth. The authors report no conflicts of interest.
The study was published online Aug. 29 in the Journal of Medical Microbiology.