SIBO, or small intestinal bacterial overgrowth, has been named as a potential cause of rosacea. Let's take a look at what it is.
Everybody knows we all have bacteria in our guts. However, there are good bacteria and bad, and there is a balance inside. There is also a difference in what bacteria live in our small intestines versus what is in our large intestines. Just as the name implies, in "small intestinal bacterial overgrowth," the bacteria typically seen in the large intestine show up in the small intestine, and there are more bacteria than normal.
It's not scientific fact that, just because this overgrowth of bacteria exists in a patient with rosacea, it's a cause. It may just be a coincidence. There may be something else about patients with rosacea that make them vulnerable to intestinal overgrowth of bacteria--in other words, it is the cart, not the horse.
A study in 2008 by Parodi et al. (Clin Gastroenterol Hepatol, 2008 Jul;6(7):759-64. Epub 2008 May 5) screened 113 rosacea patients and then treated 52 patients who were positive for small intestinal bacterial overgrowth with rifaximin or placebo. They compared these patients to 60 control patients, 3 of which also tested positive. 26 of 28 patients treated with rifaximin showed complete clearing of lesions or at least were greatly improved.
Other antibiotics are also useful for treatment, according to Puristat.com (http://www.puristat.com/bloating/sibo.aspx). Of course, there are downsides to antibiotic use as well, like diarrhea, microbial resistance, and fungal infections.
What I found interesting is the causes: any disease that causes slow gut motility, like diabetes or neuromuscular disorders; Crohn's disease; or fistulae. The keys here are inflammation and delayed gut motility for whatever reason. The delayed gut motility may be the initial insult, and that then can result in inflammation due to the body's attempt to repair it or fight the cause.
Once again, we are back to inflammation, which I believe is the problem in rosacea, and decreasing that underlying inflammation in your body will result in improvement of your skin.