The "largest known outbreak" of sexually transmitted ringworm in the United States is happening in Minnesota, according to local health officials.
In an advisory posted Feb. 11, the Minnesota Department of Health said more than 30 confirmed or suspected cases have been reported in the state's metro area since its first case was confirmed in July 2025 in a patient who sought care for a genital rash.
Sexually transmitted ringworm, known as trichophyton mentagrophytes genotype VII, or TMVII, is not a worm, but a sexually transmitted fungus that infects the skin, the health department and the Centers for Disease Control and Prevention explain.
"TMVII infections might be confused with noninfectious conditions (e.g., psoriasis) and other sexually transmitted infections, and delayed treatment might result in scarring or secondary bacterial infection and continued spread," the CDC added.
To prevent TMVII infection, the health department advises people avoid sexual or skin-to-skin contact while experiencing symptoms or in the presence of a suggestive rash, avoid using shared clothing and personal items and wash and dry clothes on high heat to kill fungal spores.
