Trichophyton soudanense, Trichophyton violaceum, and Trichophyton tonsurans in Munich: Travel- and Migration-Related Cutaneous Fungal Infections.

Introduction: Trichophyton soudanense, Trichophyton violaceum, and Trichophyton tonsurans are considered rare pathogens in Germany. They are presumed to infect people from Germany when they are traveling to tropical and subtropical areas. The incidence and the mode of infection with these three fungal pathogens in Munich were investigated to assess their significance for clinical practice.

Methods: This monocentric study was conducted at a large European academic dermatology department in Munich from January 1, 2011, till August 30, 2020. We performed a retrospective analysis of medical data of all out- and inpatients presenting at our hospital with a suspected cutaneous fungal infection.

Results: A total of 87,229 swabs were collected from 48,916 patients; 11,513 (13.2%) cultures confirmed a fungal infection. One of the three aforementioned dermatophytes was detected in 247 (2.1%) samples. The average patient age was 15.5 years (0-84 years, SD: 15.6) at the time of infection. T. tonsurans was the confirmed pathogen in 137 (55.5%) samples with increasing frequency over time. T. tonsurans spread in 11 cases through close contact with humans (kindergarten, martial arts, accommodation for asylum seekers). T. violaceum was detected in 88 (35.6%) samples with a peak in 2016 and 2017. T. soudanense was detected in 22 (8.9%) samples. A total of 46.7% of all tinea capitis cases were caused by one of these pathogens.

Conclusion: In case of tinea capitis, a travel history should be performed and rare fungal infections should be considered in the differential diagnosis.