Rosacea is a skin condition affecting more than 16 million Americans, giving them the appearance of redder, blotchy skin. The National Rosacea Society states that there is no known cause for the condition, but a new study published in the Journal of Medical Microbiology suggests it could be tiny, eight-legged creatures, living, dying, laying eggs and doing other business that results in bacterial infections in your pores.
According to the research, this is not a definitive cause yet but they did find that rosacea patients had higher densities of demodex mites on their skin, compared to control patients without rosacea. It isn't the mites directly causing the condition, they write in the abstract, but perhaps it is the larger amount that results in a "bacterial disease."
There are two species of these mites, which are in the same class as spiders, known to reside on human skin. Given that their main food source are epidermal cells and sebum components, they are commonly found in areas "particularly rich with sebaceous glands," which would be the nose, cheeks, forehead and chin. The researchers state that some rosacea patients have sebum with an altered fatty acid, which could make them more susceptible as hosts to the mites. It suggests other immunological conditions could act in the mites' favor as well.
Here is more from the study's conclusions:
Developing Demodex mites may be causative agents of rosacea through various mechanisms: they may mechanically block hair follicles, secrete digestive enzymes, destroy the epithelial barrier or trigger reactions of the immune system. So, these mites, which were long believed to exhibit commensalism with humans (a relationship in which the host was not harmed but the other species benefited), could potentially be considered parasites now.
It is believed that B. oleronius forms a symbiotic relationship with Demodex, as it does in the termite (Kuhnigk et al., 1995). On the skin of humans, this bacterium may occur in the endospore form, which enters the digestive tract of Demodex mites when they consume epithelial cells. The dead mites then decompose inside the hair follicles, where they release significant numbers of bacterial antigens, which have the potential to stimulate a strong immune response (O’Reilly et al., 2012). Thus, the intensification of blepharitis and rosacea, especially the papulopustular variant, may not be induced so much by the presence of the mites alone but by the presence of Demodex mites that carry B. oleronius in their digestive tract
Kevin Kavanagh of the National University of Ireland explained this concept more simply to New Scientist: "Their abdomen just gets bigger and bigger, and when they die and decompose they release their feces all at once in the pore." The mites do not excrete feces as they do not have an anus.
Kavanagh is hoping to further the research on this topic to link the bacteria to the disease and develop antibodies against the bacteria to lead to treatment.
This study is one io9 categorizes as one to be "[filed] away under things you desperately wish you could un-know."