Tehran University of Medical Sciences Journal of Arthropod-Borne Diseases 2322-1984 19 3 2025 12 13 1847 1847 Abozar Nasiri-Jahrodi Department of Pathobiology and Medical Laboratory Sciences, North Khorasan University of Medical Sciences, Bojnurd, Iran Hassan Bakhshi Vector-borne Diseases Research Center, North Khorasan University of Medical Sciences, Bojnurd, Iran Rezvan Rajabzadeh Non-Communicable Diseases Research Center, Sabzevar University of Medical Sciences, Sabzevar, Iran Kamy Hosseinian-Khosroshahy Department of Clinical Pathology, Dr. Khosroshahi’s Pathobiology Laboratory, Tehran, Iran Hassan Reza Rokni Student Research Committee, Gonabad University of Medical Sciences, Gonabad, Iran Mehdi Barati Department of Pathobiology and Medical Laboratory Sciences, North Khorasan University of Medical Sciences, Bojnurd, Iran Mitra Salehi Vector-borne Diseases Research Center, North Khorasan University of Medical Sciences, Bojnurd, Iran 2025 04 28 2025 11 02 Background: Hair follicle mites of the genus Demodex (Prostigmata: Demodicidae) are the most common external obligate parasites in humans, which reside in the eyelids, sebaceous glands, and ear canal, and can cause clinical dis­ease. The purpose of this study was to investigate the possible role of Demodex parasites in causing discomfort in pa­tients referred to Tehran laboratories due to hair loss. Methods: This cross-sectional study was conducted on 520 patients referred to a laboratory in Tehran, Iran, presenting with hair loss. Sampling was performed from the scalp and face, and samples were examined for Demodex mites using light microscopy. Results: The results showed that among the 520 patients referred to the laboratory, 66.15% were infected with Demo­dex. Out of 344 positive cases, 83.43% were women and 16.57% were men. Among the affected patients aged between 7 and 70 years, most patients (59.01%) were in the age group of 25.4 to 39.2 years. A high prevalence of Demodex in­festation (66.15%) was found among patients with hair loss.  Conclusion: Our findings establish a highly significant, direct correlation between the severity of hair loss and the den­sity of Demodex mite infestation (p< 0.001). We propose that high Demodex mite density is a significant contributory factor in the etiology of severe hair loss. https://jad.tums.ac.ir/index.php/jad/article/view/1847 https://jad.tums.ac.ir/index.php/jad/article/download/1847/700