The human skin microbiome has been established as being one of the master controls of dermal health. Most people are aware of the presence of ‘good’ and ‘bad’ bacteria, but there are other types of organisms present on healthy skin. The biome consists of bacteria, viruses, yeasts and mites.
The main form of mites on the skin are Demodex mites. They reside in the pores of the skin devouring sebum and other dead skin material. There are numerous strains of Demodex mites which vary according to the location they are found. In healthy skin at normal levels, demodex mites appear to release various substances known as immune reactive lipases, which may protect against S.Aureus and S.Pyogenes. Generally, demodex mites are innocuous and inconspicuous - even when their population is excessive. However, in the presence of increased lipid or sebum production or in instances of dermal immunosuppression, demodex mites flourish and start to release inflammatory chemicals. This is believed to be the basis for the inflammation and secondary bacterial infections associated with rosacea and perioral dermatitis.
The population of demodex mites may be reduced in a number of ways. Reduction of the sebum secretion of the skin via modulation of hormones or topical agents such as nicotinamide can be of use. Excess oils should be cleansed regularly from the skin without exfoliation. Oily makeup should also be avoided as this tends to provide an optimal environment for the bacteria to grow. Finally, a topical agent to reduce the excess demodex mites can be used. This can include permethrin or crotamiton.
Permethrin has been shown to be effective and safe in the treatment of rosacea. At the end of 12 weeks one study found that topically applied permethrin gave a significantly positive outcome in the severity of rosacea symptoms.
Crotamiton is a drug often used as an anti-itch medication, but it can also kill demodex mites.
Whilst there are agents more effective at killing demodex mites such as ivermectin, it is important to remember that these mites play an important role in the healthy skin. Thus, by using milder agents and reducing the number of demodex mites rather than eradicating them all together, the microbiome can be returned to normal and the skin will return to its optimal state.
Since the microbiome is so complex and demodex mites interact with other bacterial and fungal cells, it is also important in treating to ensure that the cream base nurtures the entire microbiome. Thus, it must be free from harsh antimicrobial and antifungal preservatives, is of the correct pH and contains natural oils.
If you would like more information or a product to treat your rosacea, the pharmacists at BCP will be able to give you advice.
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