Rosacea May Have a Bacterial Cause

rosacea bacteria cause demodex miteA paper published last week adds weight to the theory that bacteria may cause rosacea. The review, published in the Journal of Medical Microbiology, identifies mites as the possible culprits behind bacterial disease that could explain the occurrence of this irritating skin disorder.

Rosacea sufferers often note a connection between their symptoms, gastrointestinal health and general immune function, which would tie in with such a theory regarding bacteria and immunosuppression. It could also mean that those with rosacea could restore naturally healthy skin by improving immune system health and becoming free of the bacteria.

What is Rosacea?

Rosacea is a skin condition thought to affect around 3% of the world’s population. The classic signs of rosacea include an angry red or purplish rash across the bridge of the nose and into the cheeks and even the chin. Sufferers of the skin disorder are often self conscious as it may resemble the flush from excessive alcohol ingestion as well as the swelling of the nose that can result from alcohol abuse.

The condition may be papulopustular, meaning that raised red blotches occur. In minor cases it may look like acne, whereas more extreme cases can cause significant disfigurement and lead to scarring.

Treating Rosacea

As the precise cause of rosacea has not been identified it remains a tricky skin condition to treat. However, antibiotic treatments are often effective in reducing symptoms. Tetracycline or metronidazole may form part of rosacea treatment, along with topical antibiotics in some cases. Many sufferers also note that improvements in gastrointestinal health and the use of natural anti-inflammatories and probiotics also alleviate rosacea symptoms.

What Causes Rosacea?

The literature review was carried out by Stanishaw Jarmuda, and colleagues, at the University of Medical Sciences in Poznan, Poland. They note that it is well established that rosacea sufferers tend to have a much higher number of Demodex mites and bacteria on their skin than those free from the skin disease.

The precise relationship between such overproliferation of mites and the skin condition has not been elucidated, however, although many hypotheses abound. Jarmuda, et al, suggest that the evidence points to an etiopathogenesis of rosacea involving the Demodex mites infecting patients with a specific bacterium, Bacillus oleronius.

Bacterial Infection and Rosacea

This microorganism was identified in a Demodex mite taken from a rosacea sufferer and the bacterium was found to induce an immune system response in almost three quarters of patients (73%) with papulopustular rosacea; just 29% of controls had a similar response. What’s more, some 90.2% of patients with papulopustular rosacea had evidence of Demodex folliculorum in their follicle secretions, compared to 11.9% of controls. Such findings support the hypothesis that rosacea is caused by bacterial infection.

Do Mites Cause Rosacea?

The authors suggest that Demodex may become pathogenic when patients have compromised immune systems that allow the mite to grow uncontrollably and spread bacteria. The average density of Demodex in patients with rosacea was found by the reviewers to be 10.8 mites/cm2 compared to 0.7 mites/cm2 in non-sufferers.

Another study found that Staphylococcus epidermidis was present in nine of fifteen patients with papulopustular rosacea but that this same bacterium was not found in unaffected areas of the same patients. This bacterium is killed by antibiotics often used to treat rosacea, which may explain their efficacy.

Fighting Rosacea Infection

The exact role of Demodex mites, Bacillus oleronius, Staphylococcus epidermidis and immunosuppression remains unknown but the evidence is mounting to suggest a relationship between rosacea, lowered immunity, resulting mite infestation and bacterial infection. So far, this growing suspicion supports the use of antibiotic treatment for rosacea but it may also encourage patients to do more to improve the health of their immune systems, where possible.

If rosacea is caused by bacteria then patients may be able to restore naturally healthy skin through natural antibiotic treatments, such as tea tree oil and by improving overall immune health.


Jarmuda, S., et al, The potential role of Demodex folliculorum mites and bacteria in the induction of rosacea. J Med Microbiol. Published online August 29, 2012.

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