Copyright 2010 by Brady Barrows
If you were around in August 2007, there were headlines such as, Scientists unmask the cause of rosacea,  and UCSD Researchers Discover Cause of Rosacea  not to mention all the other headlines which created quite a stir in all the online rosacea groups and brought a lot of hope for rosacea sufferers. These articles seemed to conclude that rosacea’s mystery is resolved and within time a treatment would be found to eradicate rosacea. These startling headlines were the result of a paper published by researchers at UCSD associated with Richard L Gallo, et.al, in a study published by Nature Medicine . This paper concluded:
“These findings confirm the role of cathelicidin in skin inflammatory responses and suggest an explanation for the pathogenesis of rosacea by demonstrating that an exacerbated innate immune response can reproduce elements of this disease.” More info on cathelicidins.
If you will notice in the above statement that the findings suggest an explanation for the pathogenesis of rosacea. Gallo, et.al, never said they found the cause of rosacea. The newspapers came to the conclusion that now all the mystery of rosacea is over and we now have the cause nailed down. All we have to do is wait for the treatment. This is not exactly the truth. While the research of Gallo, et.al, at UCSD is remarkable and insightful, the jury is still out on what causes rosacea. And while the jury is still out, there is more news worth mentioning that may be related to cathelicidin, peptides or antigenic proteins.
According to The Irish Times, Irish Scientists blame bacteria as the cause of rosacea according to a different study. This study is the result of researcher Dr Kevin Kavanagh, a senior lecturer in biology at NUI Maynooth. According to The Irish Times, “Working with the Mater hospital, the researchers previously identified a Bacillus bacterium inside Demodex mites. The bacteria release two proteins that trigger an inflammation in patients with facial rosacea.” 
At least one type of bacteria is associated with demodex mites and rosacea. This bacteria is Bacillus oleronius according to an NRS press release  which quotes Dr. Kavanagh as saying, “This indicates that the Bacillus bacteria found in the Demodex mite produce an antigen that could be responsible for the tissue inflammation associated with papulopustular rosacea.” A study released in September 2007 by Dr. Frank Powell, et.al, also concluded, “Antigenic proteins related to a bacterium (B. oleronius), isolated from a D. folliculorum mite, have the potential to stimulate an inflammatory response in patients with papulopustular rosacea.”  Another study released in January 2010 also said, “The strong correlation provides a better understanding of comorbidity between Demodex mites and their symbiotic B oleronius in facial rosacea and blepharitis.” 
In the recent past, a couple of noted rosacea online gurus have dismissed the role of demodex in rosacea. One such rosacea guru said, “Rosacea experts all agree that this mite plays no real role in the development of progression of rosacea (except for the odd pustule).”  The other rosacea guru says, “I have always pushed the line that demodex mites have thus far only been proven to be innocent bystanders in rosacea symptoms.”  However, the NRS continues to sponsor research into demodex and the RRDi just released a paper by Dr. Kosta Y. Mumcuoglu and Dr. Oleg E. Akilov on demodex’s role in rosacea.  In fact, there is probably not many other type research with as many papers on the subject of demodex except for a scarce few. 
Another theory on the cause of rosacea is that irritable bowel syndrome is related to rosacea. “Rosacea may be a symptom of an unhealthy gastrointestinal system and healing the entire gastrointestinal system may be the basis for eliminating rosacea. Many people with rosacea also have been diagnosed with Irritable Bowel Syndrome (IBS), Crohn’s Disease or some for of Colitis.” 
This theory also is related to bacteria in the gut and that using antibiotics clears rosacea. An article in the St. Louis Dispatch  says that one doctor has been prescribing Xifaxan, an antibiotic for gastric problems and reports clearing of rosacea. Previously to this report a study in Italy published that eradicating the bacteria in the gut had improved rosacea. 
Another theory that has come up is that SIBO is related to rosacea. The previously mentioned rosacea online guru had this to say about SIBO and rosacea:
“This sort of abstract just make me shake my head. If you read quickly you will think that this abstract suggests that Small Intestinal Bacterial Overgrowth (SIBO) causes rosacea. What this abstract is saying that is that rosacea sufferers seem to have a higher incidence of SIBO than non rosacea sufferers.”  “The link between SIBO and the papules and pustules of rosacea is still a mystery.”  For more information on rosacea and SIBO click here.
There is also a continuing controversy as to whether H Pylori is a factor in rosacea and I have written an article on this subject for your interest.
So in conclusion, the jury is still out on what causes rosacea but it appears that the jury hasn’t ruled out demodex quite yet, despite what the rosacea gurus tell you. The headlines may one day come to another ’cause’ of rosacea or highlight the ones discussed above. Whatever happens, keep an open mind, since we still don’t know what causes rosacea. We may be surprised one day to actually read a headline that says truthfully what the cause of rosacea is.
For more information on the cause of rosacea and other theories on this subject click here.
 Scientists unmask the cause of rosacea
August 06, 2007|Alison Williams, Los Angeles Times Staff Writer
 UCSD Researchers Discover Cause of Rosacea
UCSD News Center
 Increased serine protease activity and cathelicidin promotes skin inflammation in rosacea
Kenshi Yamasaki1, Anna Di Nardo1, Antonella Bardan1, Masamoto Murakami2, Takaaki Ohtake3, Alvin Coda1, Robert A Dorschner1, Chrystelle Bonnart4,5, Pascal Descargues4,5, Alain Hovnanian4,5,6, Vera B Morhenn1 & Richard L Gallo1
Nature Medicine 13, 975 – 980 (2007)
Published online: 5 August 2007 | doi:10.1038/nm1616
 Study finds cause of rosacea
The Irish Times – Tuesday, July 14, 2009
 New Study Shows Role for Bacteria in Development of Rosacea Symptoms
NRS Press Release, May 3, 2004, Suzanne Corr / Barbara Palombo
 Mite-related bacterial antigens stimulate inflammatory cells in rosacea.
Lacey N, Delaney S, Kavanagh K, Powell FC.
Department of Biology, National University of Ireland, Maynooth, Co. Kildare, Ireland
Br J Dermatol. 2007 Sep;157(3):474-81
 Correlation between Ocular Demodex Infestation and Serum Immunoreactivity to Bacillus Proteins in Patients with Facial Rosacea,
Li J, O’Reilly N, Sheha H, Katz R, Raju VK, Kavanagh K, Tseng SC.
Ophthalmology. 2010 Jan 14,
 page 110 quote
Beating Rosacea Vascular, Ocular & Acne Forms
Geoffrey Nase, Ph.D.
Nase Publications 2001
 The Role of Demodex Mites in the Pathogenesis of Rosacea and Blepharitis and Their Control
Kosta Y. Mumcuoglu, Ph.D., Oleg E. Akilov, M.D., Ph.D.
Journal of the Rosacea Research & Development Institure, Vol.1, No.1
 For a partial list of Demodex in rosacea and acne click here.
 New way to treat skin disorder
By Cynthia Billhartz Gregorian, St. Louis Post Dispatch, 04/29/2010
 Small intestinal bacterial overgrowth in rosacea: clinical effectiveness of its eradication.
Parodi A, Paolino S, Greco A, Drago F, Mansi C, Rebora A, Parodi A, Savarino V.
Department of Internal Medicine, Gastroenterology Unit, University of Genoa, Genoa, Italy.
Clin Gastroenterol Hepatol. 2008 Jul;6(7):759-64
 SIBO eradication clears rosacea: are you serious ?
May 7th, 2008, by David Pascoe
 Gut Bacteria and Xifaxan get some press coverage
April 30th, 2010, by David Pascoe