Emerging sexually transmitted infections outbreak: Dermatophytosis among men who have sex with men in Milan, Italy

Background: Dermatophytosis is an infection of the skin or adnexa, which is extremely widespread in the environment. Sexually transmitted infections (STIs) are an increasing global public health threat, especially among men who have sex with men (MSM). This study aims to describe an outbreak of sexually transmitted dermatophytosis among MSM in our cohort between April 2022 and October 2023. Methods: This is a retrospective monocentric study including outpatients who were diagnosed with at least one episode of dermatophytosis between March 2010 and October 2023 at the Infectious Diseases Unit of San Raffaele Scientific Institute, Milan, Italy. Mycosis diagnosis was mainly clinical following the medical visit and physical examination. Results: Overall, 107 people were diagnosed with dermatophytosis between March 2010 and October 2023. All 56 cases observed since April 2022 included 55 MSM and 1 female; compared to before 2022 there was a total diagnosis of 51 cases. Conclusions: These results highlight the evident increase in the incidence of mycotic infections among MSM, followed in our center. We are dealing with a new entity of sexually transmissible infections, in addition to the existing diseases that are being studied.