Doctors are warning of a new strain of “ringworm” called Trichophyton mentagrophytes genotype VII, a sexually transmitted fungal infection that can be spread on skin contact.

Trichophyton mentagrophytes are a form of dermatophytes (fungi that thrive on keratin that cause common skin infections) spread through direct contact with an infected host (human or animal) or from a contaminated environment.

The primary symptom, a round rash, can appear anywhere on the body but mainly on the penis, vagina, buttocks, and limbs.

The first case was reported in the United States on June 5. According to reports, the man had recently visited England, Greece and California. He reported having sexual encounters with men during his travels, none of whom disclosed having the infection.

“Healthcare providers should be aware that Trichophyton mentagrophytes type VII (TMVII) is the latest in a group of severe skin infections to have now reached the United States,” said NYU Grossman School of Medicine’s Dr Avrom Caplan in a New York Post article.

Dr John Zampella, senior author of the TMVII study, found TMVII infections respond to standard antifungal therapies like Lamisil but can take months to clear and may be confused with eczema-related lesions, posing a greater challenge for dermatologists.

According to the Centers for Disease Control and Prevention (CDC), “For most patients [in their testing] sexually transmitted dermatophytosis was likely. This hypothesis is supported by the sites of the infection (external genitalia, buttocks, face), the high-risk STI profile of the patients.”