What causes Acne rosacea?

Recent research has suggested that the Demodex mite is the cause of Acne rosacea. Monica Wilde reviews the reports and starts to explore herbal extracts that may help.

by Monica Wilde
June 2013

A review published in the Journal of Medical Microbiology 1 examines the link between bacteria and rosacea. This review, carried out by the National University of Ireland, concludes that rosacea is probably triggered by bacteria that inhabit tiny mites that naturally live in our skin.

Acne rosacea is the name of a common skin condition characterised by reddened and inflamed skin especially on the cheeks, nose and chin. In extreme cases, scarring lesions can form. Rosacea affects around 3% of the population – usually fair-skinned women aged 30-50 and particularly those with weak immune systems. Doctors often treat the condition with antibiotics, even though a bacterial cause has never been fully proven. About 1000 species of bacteria live naturally on our skin. This is normal.

Examples of Acne rosacea

Another natural inhabitant of our skin is a mite called Demodex folliculorum. It usually lives harmlessly inside the sebaceous gland and hair follicle shaft around the hair follicles of the face. This is perfectly normal. However, they increase in number as you get older and also if your skin gets damaged e.g. after exposure to sunlight. It is known that people with rosacea have higher numbers of Demodex mites living in their skin than people who don't have rosacea and the researcher believe that the mites may well trigger the onset of rosacea. An increase in mite density in the face is found in perioral dermatitis - a facial rash located mainly around the mouth and prevalent in young women, caused by long-term use of local steroids or other immunomodulating drugs2. Higher numbers of Demodex mites have been noted in patients undergoing immunosuppressive therapy, for example children receiving chemotherapy for leukaemia3, patients with HIV-infection or AIDS4,5 and chronic dialysis patients6.

Recently, a bacterium Bacillus oleronius was isolated from inside a Demodex mite. It was found to produce molecules that trigger an immune reaction in rosacea patients. Other studies have shown patients with varying types of rosacea react to the molecules produced by this bacterium – exposing it as a likely trigger for the condition. What’s more, this bacterium is sensitive to the antibiotics used to treat rosacea.

Researcher Dr Kevin Kavanagh explained, “The bacteria live in the digestive tracts of Demodex mites found on the face, in a mutually beneficial relationship. When the mites die, the bacteria are released and leak into surrounding skin tissues - triggering tissue degradation and inflammation.”

“Once the numbers of mites increase, so does the number of bacteria, making rosacea more likely to occur. Targeting these bacteria may be a useful way of treating and preventing this condition,” said Dr Kavanagh. “Alternatively we could look at controlling the population of Demodex mites in the face. Some pharmaceutical companies are already developing therapies to do this, which represents a novel way of preventing and reversing rosacea, which can be painful and embarrassing for many people."

From a herbalists' perspective, most plants contain natural antibiotics that may well help. In their own interest, they produce complex phytochemicals that help to defend themselves against insects, microbes and bacterium. Using gentle non-chemical, non-irritating skin care products that contain high proportions of herbal extracts is likely to confer these benefits from plants to help keep levels of mites and bacteria under control. As a single plants often has a range of compounds with antibacterial activity, plant extracts are also often still effective as complex 'combination antibiotics' even when bacterium have become antibiotic resistant.

Herbalists also often recommend liver herbs to stimulate a sluggish bowel. This helps to detoxify and restore a better state of well-being, allowing the immune system to function better, so that the patient can return to health. Sensible eating, a good intake of vitamins (especially A and C, and zinc) will support health balance. This should be done while also treating the rosacea topically.

Externally, creams and gels containing calendula flower extract, liquorice extract and lavender oil are often recommended by herbalists for use by people with rosacea. All three of these herbs (and many essential oils) are renowned for antibacterial and antimicrobial activity.

Herbalists also recommend internal remedies such as Echinacea angustifolia. This was originally used by American Indians for blood poisoning (septicaemia) and skin infections from wounds or bites. More recently echinosides, natural compounds found in this root, have been shown to have an antibiotic action with 6mg being equivalent to 1mg of penicillin. Clinical trials have also shown that in the treatment of Candida albicans, that topical treatment works better and is far less likely to reoccur if Echinacea angustifolia is also taken orally during the treatment. A useful compound of E. angustifolia root with antiseptic skin herbs wild indigo and fumitory is the THR licensed Elixir of Echinacea. Please note that the commonly available Echinacea purpurea does not contain echinosides and is only used for treating colds and flu so do make sure if trying Echinacea that you take the right species. 


1. Journal of Medical Microbiology.
2. Fujiwara et al., 2010
3. Ivy et al., 1995
4. Aquilina et al., 2002
5. Dominey et al., 1989
6. Karincaoglu et al., 2005