Background: There are controversial reports about the role of Demodex mites in pathogenesis of acne rosacea. The aim of this study was to examine the relationship between the presence and number of Demodex mites and the pathogenesis of rosacea. Methods: In this case-control study, the prevalence of Demodex mites was studied in facial biopsy of 75 patients with acne rosacea as case group, and in 75 patients with discoid lupus erythematosus and 75 patients with actinic lichen planus as control groups. Results: The prevalence of Demodex mites in patients with acne rosacea (38.6%) was significantly higher than the patients with discoid lupus erythematosus (21.3%) and actinic lichen planus patients (10.6%) (P < 0.001). Conclusion: This study suggests that Demodex mites may play a role in pathogenesis of rosacea but it is not clear whether rosacea merely provides a suitable environment for multiplication of mites, or the mites play a role in the pathological changes.

Background: Rosacea is a common chronic and recurrent skin disease whose etiology is not precisely clear. This study aimed to investigate the relationship between rosacea and Demodex mite infestation in patients referred to the medical centers of Tabriz University of Medical Sciences during 2023. Methods: Patients’ information, including age, gender, and clinical symptoms of rosacea diagnosis, was recorded. 60 out of 71 patients underwent standard superficial skin biopsy with a thickness of 5 μm from their faces, with a drop of immersion oil, and were examined under a light microscope. Results:  The mean Demodex density was 19. 20 mites/cm². Of these 60 rosacea patients, 47 (78. 3%) were female and 13 (21. 7%) were male. The highest Demodex mite infestation was in the 31_40 age group (38%). Out of 50 patients with positive Demodex (83. 3%), 41 (68. 3%) were related to D. folliculorum and 9 (15%) were related to D. brevis. Of the 41 patients infected with Demodex, 31 (out of 47, 66. 0%) were women and 10 (out of 13, 76. 9%) were men. The p-values for the relationships between age, gender, and mite species with mite count were all greater than 0. 05. This indicates no statistically significant evidence of a direct relationship.  Conclusion: Demodex mite density was higher in rosacea than the normal benchmark of <5 mites/ cm². This strong association suggests Demodex overpopulation plays a key role in the disease. Therefore, treatment strategies for rosacea should include acaricidal therapy targeting the mites.

Background: Demodex spp., a cosmopolitan mite, can exist as a commensal or parasitic organism. This study aimed to investigate the prevalence of Demodex spp. infestation in patients with common skin diseases and explore the potential association between demodicosis and these conditions in Urmia, northwest Iran. Methods: A total of 246 patients attending the Skin Polyclinic of Iranian Urmia Taleghani Hospital were enrolled in the study. Samples were taken from the nose wings, cheeks, and forehead regions of the face area of the persons using the standard superficial skin biopsy method. Results: Demodicosis was detected in 43 (16.3%) patients, with 42 cases attributed to D. folliculorum and 1 case to D. brevis infestation. The highest positivity was found in the 31‒50 (21.4%) and 51‒72 (22.2%) age groups. In the rela­tionship between demodicosis and skin diseases, Demodex spp. was found in 13 (32.5%) of 40 patients who had skin disease; 6 of these patients with rosacea (42.9%) and 7 with eczema (29.2%). Mite infestation was found in 6 (37.5%) of 16 patients who had hemodialysis due to renal insufficiency. Furthermore, 46.7% of positive patients reported using common goods. The prevalence of demodicosis was similar among patients residing in villages (17.2%) and cities (17.6%). Conclusion: This study sheds light on the potential association between Demodex infestation and common skin diseas­es such as rosacea and eczema in Urmia, Iran. Therefore, there is a pressing need to augment research endeavors on de­modicosis.

Background: Demodex is a genus of mites living predominantly in mammalian pilosebaceous units. They are commonly detected in the skin of face, with increasing numbers in inflammatory lesions. Causation between Demodex mites and inflammatory diseases, such as rosacea, blepharitis, perioral and seborrhoeic dermatitis or chalazion, is controversially discussed. Clinical observations indicate a primary form of human Demodex infection. The aim of this review was to highlight the biological aspects of Demodex infestation and point out directions for the future research. Methods: We conducted a broad review based on the electronic database sources such as MEDLINE, PubMed and Scopus with regard to the characteristics of the Demodex species, methods of examination and worldwide epidemiology, molecular studies and its role in the complex human ecosystem. Results: Demodex mites are organisms with a worldwide importance as they act in indicating several dermatoses, under certain conditions. However, correlations between Demodex and other parasites or microorganisms occupying one host, as well as interactions between these arachnids and its symbiotic bacteria should be considered. There are few methods of human mites' examination depending on purpose of the study. Nevertheless, paying attention must be needed as polymorphism of Demodex species has been reported. Conclusion: Overall, the present review will focus on different aspects of Demodex mites’ biology and significance of these arachnids in human’ s health.

Background: Demodicosis is one of the most prevalent skin diseases resulting from infestation by Demodex mites. This parasite usually inhabits in follicular infundibulum or sebaceous duct transmitted through close contact with an infested host. Methods: This study was carried from September 2014 to January 2016 at Tehran University of Medical Sciences, Tehran, Iran. DNA extraction and amplification of 16S ribosomal RNA was performed on four isolates, obtained from four patients and identified morphologically through clearing with 10% Potassium hydroxide (KOH) and microscopical examination. Amplified fragments from the isolates were compared with GenBank database and phylogenetic analysis was carried out using MEGA6 software. Results: A 390 bp fragment of 16S rDNA was obtained in all isolates and analysis of generated sequences showed high similarity with those submitted to GenBank, previously. Intra-species similarity and distance also showed 99. 983% and 0. 017, respectively, for the studied isolates. Multiple alignments of the isolates showed Single Nucleotide Polymorphisms (SNPs) in 16S rRNA fragment. Phylogenetic analysis revealed that all 4 isolates clustered with other D. folliculorum, recovered from GenBank database. Our accession numbers KF875587 and KF875589 showed more similarity together in comparison with two other studied isolates. Conclusion: Mitochondrial 16S rDNA is one of the most suitable molecular barcodes for identification D. folliculorum and this fragment can use for intra-species characterization of the most human-infected mites.