Analysis of Causative Factors and Potential Predictors of Onychomycosis: A Retrospective Single-Center Study in Poland.

Onychomycosis is a fungal nail infection which has a considerable impact on the quality of life of patients. The aim of this study was to analyze onychomycosis cases with respect to fungal species, infection sites, and patient demographics such as age and sex. Furthermore, we assessed whether simple clinical and demographic data could predict positive results for mycological culture. A retrospective analysis of 2722 patients who had nail samples investigated with direct microscopy and mycological culture was performed. The fungi most frequently identified were Trichophyton rubrum in the toenails and Candida albicans in the fingernails, with a detailed incidence varying by age and sex. Predictive models, including logistic regression and k-nearest neighbors, did not provide clinically useful accuracy. Therefore, it is necessary to perform confirmatory diagnostics before starting antifungal treatment.