Azelaic acid has been demonstrated to be effective for the treatment of rosacea. It is available as a 20% cream or a 15% hydrogel. It reduces inflammatory lesions and erythema in rosacea patients and also inhibits neutrophilic ROS (Reactive Oxygen Species). In the neutrophil system azelaic acid inhibits the ROS formation in a dose-dependent manner, markedly decreasing the number of free radicals. In the xanthine-xanthine oxidase system, none of the ROS generated was decreased by any dose of azelaic acid, indicating that azelaic acid does not scavenge generated ROS, but rather inhibits cell metabolism, possibly by decreasing enzymatic activity within the cell membrane.
Azelaic acid is probably the only non-pharmaceutical ingredient that has been demonstrated to exhibit good activity for the treatment of rosacea, without side effects.
This pharmaceutical product is not allowed to be used in personal care & cosmetic products as well as in medical devices. Brimonidine, applied as a gel or as a stick, is reasonably effective for redness reduction in mild cases of rosacea. It functions by vasoconstriction of the small blood vessels. Brimonidine binds to the cellular α-2-adrenergic receptors of the small veins, leading to vasoconstriction. Consequently the transport of blood through these small blood vessels is reduced resulting in a reduced facial redness. The effects become visible after 6-12 hours and are fully reversible. Brimonidine is not a cure for rosacea, and that is also the case metronidazole. Brimonidine is also used to lower the intraocular pressure.
Metronidazole is considered to an antibiotic, which also used for the treatment of bacterial infections. It is ineffective for yeast infections such as vaginal yeast infections caused by e.g. Candida albicans.
The application of antibiotics, mostly tetrecyclines, for the treatment of rosacea is exclusively reserved for medical professionals. Antibiotics are not allowed in personal care & cosmetic products and medical devices. Antibiotics for the treatment of rosacea are mostly taken orally. Orally taken antibiotics are doxycycline & minocycline (tetracyclines).
The side effects of these antibiotics are numerous: skin rash, upset of the stomach and intestine and fungal infections. Sometimes the side effects can quite serious indeed, such as severe allergic reactions (difficult breathing, facial swelling), destruction of the intestinal flora (bloody diarrhoea), vaginal candidiasis and mouth sores. Combined with potential antibiotic resistance the use of antibiotics for the treatment of rosacea should only be considered if there are no other options left, having said that the efficacy of antibiotics for the treatment of rosacea are not well proven.
Virtually all antibiotics have cytotoxic properties and have distinct CMR and hormone disrupting properties. Antibiotics should not be used during pregnancy, unless unavoidable. In actual fact, the use of antibiotics for the treatment of rosacea is sincerely discouraged.
In case of severe rosacea that does not respond to antibiotics isotretinoin may be helpful. Isotretinoin is also a powerful oral acne drug that also helps to clear up acne-like lesions of rosacea. Isotretinoin has severe side effects and should not be used during pregnancy or planned pregnancy as it causes serious birth defects (teratogenic activity).
Isotretinoin is not compatible with oral antibiotics, oral contraceptives and particular botanicals such as St.John’s Wort. This botanical product has been reported to deactivate oral contraceptives.
A number of alternative therapies have been proposed for the treatment of rosacea. Examples are colloidal silver, emu oil and oregano oil. No conclusive evidence supports the idea that any of these substances are effective.
Chrysanthellum indicum contains phenylpropenoic acids and flavonoids, and has a well-documented effect on vascular wall permeability and increase of the mechanical resistance of capillaries. Particular flavonoids such as apigenin, rutin, silymarin and naringenin have been reported to strengthen the capillaries. The combination of flavonoids with azelaic acid is considered challenging because of the absence of side reactions, but much more information must be gathered on the functionality of flavonoids.