From the Guidelines
Demodex mites are indeed associated with rosacea, as evidenced by the relationship between Demodex folliculorum density and markers of inflammation in the skin of rosacea patients. These microscopic mites, particularly Demodex folliculorum, are found in significantly higher numbers on the skin of rosacea patients compared to those without the condition 1. The connection between these mites and rosacea involves several mechanisms: the mites can trigger inflammatory responses, their waste products may irritate the skin, and they can disrupt the skin barrier.
Treatment Options
Treatment options targeting these mites include topical medications like ivermectin 1% cream, which has been shown to reduce demodex mite density and improve cutaneous inflammatory markers in rosacea patients 1. A 12-week pilot study demonstrated clinical improvement with in vivo reduction of demodex mite density and improved cutaneous inflammatory markers with once-daily ivermectin cream 1% 1.
Key Findings
Key findings from the study include:
- Diminished mite density occurred in conjunction with downregulation of inflammatory markers at treatment weeks 6 and 12 1
- All subjects improved, with 16 of the 20 attaining an IGA score ≤ 1 (clear or almost clear) 1
- Treatment success, defined by IGA as “clear” (0) or “almost clear” (1) at 12 weeks, was higher in the treated subjects, with 38.4% (study 1) and 40.1% (study 2) of subjects achieving treatment success compared with 11.6% and 18.8% in the vehicle groups 1
Clinical Implications
The association between Demodex mites and rosacea has significant clinical implications, as treatments that reduce mite populations can be effective for many patients with this chronic inflammatory skin condition. Therefore, ivermectin 1% cream is a recommended treatment option for rosacea patients, particularly those with high demodex mite density.
From the Research
Demodex Mites and Rosacea
- Demodex mites have been found to be associated with rosacea, with higher densities of mites in the skin of rosacea patients compared to controls 2, 3, 4.
- The presence of Demodex mites is thought to play a role in the induction and persistence of rosacea, potentially through the over-proliferation of mites in damaged skin or the production of sebum with an altered fatty acid content 2.
- Demodex-associated bacteria, such as Bacillus oleronius and Staphylococcus epidermidis, may also contribute to the pathogenesis of rosacea 2, 3.
Treatment and Management
- Topical antiparasitic agents, such as ivermectin and praziquantel, have been shown to be effective in decreasing the severity of papulopustular rosacea, providing additional evidence for the role of Demodex mites in the disease 5.
- Treatment with oral metronidazole and ivermectin cream has also been successful in managing granulomatous rosacea in immunosuppressed patients 6.
- Reducing Demodex mite density through treatment may help to decrease the severity of rosacea and slow its progressive nature 4.
Demodex Mite Density
- Studies have used reflectance confocal microscopy (RCM) to determine Demodex mite density in rosacea patients, finding significantly higher densities in patients with papulopustular rosacea (PPR) and erythematotelangiectatic rosacea (ETR) compared to controls 4.
- The mean number of mites per follicle was also found to be higher in PPR and ETR patients, with a cut-off value of 0.17 and above indicating mite infestation 4.