Conventional Diagnostic Approaches to Dermatophytosis: Insights from a Three-Year Survey at a Public Dermatology...

Background/Objectives: Dermatophytosis is a widespread superficial fungal infection affecting skin, hair, and nails. Its diagnosis is often based on conventional methods such as microscopy and fungal culture. Laboratory confirmation is essential for guiding appropriate treatment and preventing the misuse of antifungal agents, which can contribute to the emergence of antifungal resistance. We retrospectively assessed the burden and species distribution of dermatophytosis in individuals attending a public dermatology institute in Italy over a 3-year period (2019-2021). Methods: We analyzed 3208 samples from 3037 individuals with clinical suspicion of superficial mycosis. All samples underwent direct microscopic examination and fungal culture. Data were stratified by demographics, body site, and fungal species. Agreement between diagnostic methods was assessed using raw concordance and Cohen's Kappa statistic. Results: Dermatophytes were confirmed in 667 samples (20.8%). Buttocks and genitals showed the highest positivity rates (37.5% and 36.4%, respectively). T. rubrum (56.8%) and T. mentagrophytes (30.7%) were the predominant species among the dermatophyte-positive specimens. Agreement between microscopy and culture was good (raw concordance: 91.6%, Cohen's Kappa: 0.77, 95% CI: 0.74-0.79). Younger age and male gender were significantly associated with dermatophyte positivity. Conclusions: Our data provide updated epidemiological insights into dermatophytosis in Italy and support appropriate antifungal stewardship. Laboratory confirmation remains essential for an accurate diagnosis and species identification, thus avoiding other non-dermatophytic or non-infectious conditions being treated as dermatophytosis.