Prevalence of Demodex Folliculorum and Demodex Brevis in Patients with Blepharitis and Chalazion

Purpose: Demodex folliculorum and Demodex brevis are common ectoparasites on skin that also can lead to blepharitis and chalazion. The aim of our study is to determine the prevalence of Demodex spp. in eyelashes of patients diagnosed with chronic blepharitis and chalazion. Methods: This study included 330 patients diagnosed with chronic 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 spp. were determined. Results: 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). Conclusion: The results of the study show that Demodex acari infestations should be considered in chronic blepharitis and chalazion.

Demodex folliculorum (Trombidiformes: Demodicidae) and Demodex brevis Prevalence in an Extreme Environment of Chile

The prevalence of mites of the genus Demodex and their associations with host age, gender, workplace, and comorbid skin and ocular conditions were studied in participants in Antofagasta, Chile, which is in a region with an extreme environment. We examined 680 participants aged 18–88 yr using standardized surface skin biopsies. Among them, Demodex had a prevalence of 13.5 % (95% confidence interval, 10.88–16.17). A slightly higher prevalence was observed in males (51.1%; 95% confidence interval, 40.9–61.3; nonsignificant) and participants in the 69–88 yr age group (50.0%; 95% confidence interval, 23.8–76.2; P &lt; 0.05). Regarding the species involved, Demodex folliculorum was found in 89.1% (CI 82.7–95.5) of cases, while D. brevis was found in the remaining 10.9% of cases. A higher prevalence (25.0% CI 16.1–33.91) was observed in participants who worked indoors in generally enclosed and dust-rich environments (such as theaters, libraries, and administrative offices). There was also a strong association between Demodex prevalence and conjunctival hyperemia, with 35.9% (95% confidence interval, 9.1–35; OR 17.9) of the Demodex positive participants having this pathology compared to 10.3% of the noninfested participants. In summary, the prevalence of Demodex in Antofagasta, Chile (13.5%) was toward the lower end of the range reported among other regions around the world. Environmental factors such as exposure to the sun (including ultraviolet rays) or environmental pollution may affect the mites. In addition, Demodex genetics (related to virulence) and the ocular or skin microbiota may positively or negatively influence infestation and pathology.

Scale and Pustule on Dermoscopy of Rosacea: A Diagnostic Clue for Demodex Species

Background: Demodex mites are highly found in the skin of patients with rosacea.The diagnosis of Demodex can be made by standardized skin surface biopsy. Dermoscopy is a tool used in the noninvasive diagnosis of various dermatological diseases. Objectives: To determine whether dermoscopic features of demodicosis are associated with the result of standardized skin surface biopsy in patients with rosacea and to compare dermoscopic features of rosacea in Demodex-positive and negative samples and Demodex type. Methods: A total of 30 patients (7 male, 23 female) were included in the study. Dermoscopic examination was performed on both the clinically most severely affected areas and adjacent healthy skin. The skin surface biopsy sample was taken from the same place from where the dermoscopic image was taken. Results: A total of 83 (lesion n = 60, non-lesion n = 23) areas were evaluated. Demodex was detected in 60.2% (n = 50) of the samples. Half of these samples revealed only Demodex folliculorum, and the remaining half revealed D folliculorum and Demodex brevis. Of theDemodex-positive samples, 88% had Demodex tails (P =0.001) and68% Demodex follicular openings (P = 0.002) on dermoscopy. In D folliculorum+D brevis-positive samples, the rate of scale and pustule was higher than D folliculorum-positive samples (P = 0.017 and P = 0032,respectively). Conclusions: The sensitivity and specificity of Demodex tail are higher than Demodex follicular opening and scale and pustule detection with dermoscopy and may indicate the coexistence of both D folliculorum and D brevis.

Activity of Plant Essential Oils Against Demodex folliculorum and Demodex brevis

Infestation with Demodex spp. is an increasingly common dermatological and ophthalmic problem. Preparations for daily cleaning of eyes and the surrounding area (gels, soaked wipes) contain mainly tea tree oil or terpinen-4-ol. To date, the use of other essential oils supporting the fight against demodicosis is limited due to insufficient number of clinical trials. The aim of this review is to present the most commonly used medicinal plants and their active ingredients used in the treatment of infestation with Demodex folliculorum and Demodex brevis, with particular emphasis on tea tree oil. PubMed, Embase and Google Scholar databases were searched for the selection of scientific literature. (JNNN 2020;9(4):160–165) Key Words: Demodex brevis, Demodex folliculorum, essential oil, parasitic disease, tea tree oil

Demodicosis in humans as a current problem in dermatology and ophthalmology

Introduction. Human Demodex mites (Demodex folliculorum and Demodex brevis) are ectoparasites living inside the sebaceous glands and hair follicles. In most people, their presence is of no consequence. However, several conditions or various external factors might contribute to pathological Demodex infestation resulting in demodicosis. Many different cutaneous diseases can resemble demodicosis leading to misdiagnosis.Aim. This paper aims to present information about demodicosis and provides a clear clinical portrait of demodicosis in order to distinguish it from other mimicking inflammatory dermatoses. Material and Methods. The literature search was conducted in the English and Polish language via the PubMed database and Main Medical Library. The articles regarding Demodex infestation were selected. Results. There is some evidence about the role of Demodex in the development of rosacea, blepharitis and clinical correlation between them.Conclusions. More attention should be drawn to Demodex as it plays a significant role in the development of various clinical entities in both dermatology and ophthalmology.

Nużeniec jako czynnik etiologiczny przewlekłego zapalenia brzegów powiek

Przewlekłe zapalenia brzegów powiek to choroby aparatu ochronnego oka i jego powierzchni, z którymi praktykujący lekarz okulista spotyka się niemal na co dzień. Etiologia tych schorzeń pozostaje wciąż niewyjaśniona, podobnie jak i mechanizmy patogenetyczne prowadzące do wystąpienia objawów tych chorób. Ponieważ liczne doniesienia wskazują na roztocza z rodzaju Demodex jako czynnik etiologiczny niektórych schorzeń oczu oraz skóry, jest wielce prawdopodobne, że infestacja tymi roztoczami może również odgrywać rolę w etiologii i patogenezie przewlekłych zapaleń brzegów powiek. U człowieka pasożytują dwa gatunki roztoczy z rodzaju Demodex: Demodex folliculorum i Demodex brevis. Demodex spp. występują u ludzi na całym świecie. Wraz z wiekiem wzrasta odsetek osób zakażonych, który ok. 60 r. ż wynosi niemal 84%. Nużeniec może przyczyniać się do rozwoju stanu zapalnego brzegów powiek nie tylko w sposób bezpośredni, ale także pośrednio, jako tzw. wektor dla bakterii i grzybów chorobotwórczych. Celem pracy było zbadanie obecności nużeńców w mieszkach włosowych rzęs i ich potencjalnego udziału w etiologii przewlekłych zapaleń brzegów powiek. Przeprowadzone badania w grupie 237 osób (97 osób z PZBP i 145 osób bez PZBP) jednoznacznie wskazują na istnienie zależności pomiędzy infestacją D. folliculorum lub D. brevis a występowaniem przewlekłego zapalenia brzegów powiek. Potwierdzanie dodatniej korelacji nużeniec-PZBP w populacji polskiej dostarcza kolejnego dowodu na patogenną rolę jaką odgrywają te roztocza w rozwoju chorób oczu.

Truncal Demodex Folliculitis

Demodex brevis and Demodex folliculorum are two species of ubiquitous parasites whose role in human disease continues to be fully elucidated. Demodex most commonly causes symptomatic infestations confined to the head and neck. Clinically, symptoms may mimic acne vulgaris, papulopustular rosacea, perioral dermatitis, and seborrheic dermatitis, among others. Practitioners must maintain a high level of suspicion to avoid a misdiagnosis.

A Case Report of Human Demodicosis in a Patient Referred to a Dermatology Clinic in Tabriz, Iran

Background: The genus Demodex belongs to the order Prostigmata and the family Demodecidae that has several species of uncommon mites, some of which cause severe scabies in animals. There are two species of this mite that cause disease in humans, including Demodex folliculorum, which is known as hair follicle mite, and Demodex brevis. This disease is more common in women than in men. Case Presentation: The patient is a 36-year-old woman living in one of the villages of Tabriz city who referred to a dermatologist following severe itching and hyperkeratosis (abundant dandruff) of the cheeks. Then, she was introduced to the laboratory for preparing a slide from a sample taken from the patient’s cheeks. A large number of Demodex mites were observed in the microscopic test of the sample. Conclusion: In patients referred to skin clinics with scaling and itching, especially in the head and face, the complication may be due to Demodex infection. Therefore, it is suggested that demodicosis be considered in differential diagnosis in such patients.