The prevalence of demodex folliculorum and demodex brevis in patients diagnosed with blepharitis and chalazion and the effects of some essential oils on in vitro lifespan

Demodex folliculorum and Demodex brevis are common ectoparasites on skin that also can lead to blepharitis and chalazion. Natural products such as tea tree oil are used for ocular demodicosis, which can take a long time to treat. The aim of our study is to determine the prevalence of Demodex spp. in eyelashes of patients diagnosed with blepharitis and chalazion and to investigate the effects of some essential oils on in vitro mite lifespan. This study included 330 patients diagnosed with blepharitis, 70 patients diagnosed with chalazion and 130 volunteers without any ocular problems. Patient eyelashes were examined under a light microscope at magnifications of × 40, × 100 and × 400. Demodex species were determined and the killing times of mineral oil, tea tree oil, black seed oil, St. John's Wort oil, sage oil and thyme oil were recorded. The active ingredients of thyme, tea tree and sage oils with the most successful results were determined by GC / MS method. Parasite prevalence was significantly higher in blepharitis (75.5%) and chalazion groups (70%) compared to the control group (16.2%) (p <0.001). The prevalence of D. folliculorum in the blepharitis group and D. brevis in the chalazion group was found to be significantly higher compared to other groups (p <0.05). The average number of mites per eyelash was found to be significantly higher in patients with Demodex positive blepharitis (p = 0.001) and in chalazion patients (p = 0.047) than in the control group. It has been determined that mite positivity increases with age in blepharitis and control groups (p <0.05). In the group with blepharitis, it was found that mite positivity was significant in the presence of symptoms (p = 0.0001) and Demodex positivity decreased as the education level of individuals increased (p = 0.039). It was determined that thyme oil is the most effective oil in killing mites. It was determined that 1% concentration of thyme oil has more effective killing time than 5% concentrations of tea tree oil and sage oil (p <0.0001). The most important active ingredients were carvacrol in thyme oil, terpinen-4-ol in tea tree oil, and 1.8-cineol in sage oil. According to the literature research this study is the first one which was conducted in Turkey about the prevalence of Demodex spp., in patients with chalazion and and the effects of some essential oils on in vitro lifespan. In addition, the first steps were taken that thyme oil and its products can be used in therapy.Key words: Demodex spp., blepharitis, chalazion, essential oil, thym oil.