Epidemiology of dermatophytes isolated from superficial dermatological samples taken during 2020-2023 in Zaragoza...

Dermatophytoses are transmissible infections that affect one billion people worldwide and have a significant impact on public health. Dermatophytes distribution evolves geographically and over time. Consequently, local epidemiology should be periodically assessed to control infection.

To describe the local distribution of dermatophytes and types of dermatophytosis through the analysis of samples from patients with suspected superficial mycoses, and to identify areas of improvement.

A retrospective epidemiological analysis of mycological culture results from skin, hair and nail samples referred to the mycology lab in the Hospital Clínico Universitario Lozano Blesa, Zaragoza (Spain) between 2020 and 2023 was performed, and the results statistically analyzed.

4371 specimens (skin: 41.4%; hair: 5.1%; nails: 53.5%) were cultured using standard procedures. The demand for testing increased by 53% over a 4-year time period and a dermatophyte positivity rate of 16.7% (n=731) was found. The species distribution was the following: Trichophyton rubrum (56%), Trichophyton tonsurans (11.3%), Microsporum canis (11.8%), Trichophyton interdigitale (7%), Trichophyton. mentagrophytes (5.8%), Microsporum audouinii (3.8%) and other species (4.9%), with an anthropophilic to zoophilic ratio of 4:1. The dermatophytoses clinical forms found were tinea unguium (39.6%), associated to population over 45 years, tinea corporis (24.7%) and tinea capitis (10.6%), both associated to people with less than 16 years group, tinea pedis (17.5%), mainly observed in people aged 31-45 years; other forms accounted for 7.6%. Finally, the Emergency department requested 11.9% of the mycological tests.

Local epidemiology of dermatophytoses highlights the predominance of anthropophilic species, whereas 35 years ago zoophilic species represented 80% of the isolates. Interestingly, mild superficial lesions are frequently and inappropriately brought to the Emergency department.