Tehran University of Medical Sciences Iranian Journal of Microbiology 2008-3289 17 5 2025 10 14 854 860 Mahsa Naeimi Eshkaleti Department of Medical Parasitology and Mycology, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran Seyed Jamal Hashemi Department of Medical Parasitology and Mycology, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran Sadegh Khodavaisy Department of Medical Parasitology and Mycology, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran Roshanak Daie Ghazvini Department of Medical Parasitology and Mycology, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran Kazem Ahmadikia Department of Medical Parasitology and Mycology, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran Abbas Rahimi Foroshani Department of Statistics and Epidemiology, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran Ali Ahmadi Department of Medical Parasitology and Mycology, School of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran Nasibeh Ghasemi Department of Medical Parasitology and Mycology, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran 2025 05 13 2025 08 05 Background and Objectives: Dermatophytosis is a significant worldwide health concern, particularly in tropical and subtropical regions. Tinea unguium (TU) and Tinea capitis (TC) are among the most prevalent clinical manifestations of dermatophytosis caused by several dermatophyte fungi. This study investigated the molecular epidemiology and distribution of dermatophytes causing TU and TC in Tehran, Iran. Materials and Methods: From March 2023 to March 2024, a clinical mycology center in Tehran received 342 suspected cases of TU and TC. The diagnostic methods included the conventional and molecular methods by sequencing the ITS region of ribosomal DNA. Results: Overall prevalence of dermatophytosis was 59/342 (17.2%) among suspected patients by direct examination. TU and TC were diagnosed in 31/59 (53%) and 28/59 (47%), respectively. The final prevalence among suspected patients was 43/342 (12.5%) by PCR-sequencing, and TC accounted for the largest group of them, 25/43 (58%). Females represented the largest group of suspected TU cases (204/303, 67%; mean age: 57 years), while males predominated among TC patients (28/39, 74%; mean age: 10 years). PCR-sequencing revealed Trichophyton tonsurans was the most common agent of TC, 22/25 (88%), and Trichophyton indotineae emerged as a notable cause of TU in 5/18 (28%) of confirmed cases. Conclusion: In our study, T. tonsurans remained the predominant cause of TC, while T. indotineae emerged as a significant cause of TU. Agreement between conventional and molecular methods was substantial (κ=0.73, 95% CI: 0.61–0.85), with 81.8% misidentification of the T. mentagrophytes complex but complete accuracy for T. tonsurans and Microsporum canis. https://ijm.tums.ac.ir/index.php/ijm/article/view/5494 https://ijm.tums.ac.ir/index.php/ijm/article/download/5494/1832