Ringworm is a fungal infection that causes a ring-shape rash that is often red, itchy, and scaly at the center. Rashes can appear anywhere on the skin, but often occur on the scalp, feet, or groin area. Ringworm is not a worm. It’s caused by a specific type of fungi called dermophytes that are spread through skin-to-skin contact or contact with some objects like clothing or sheets.

Ringworm isn’t usually considered sexually transmitted. Since 2024, however, there’s a new type circulating in the United States caused by Trichophyton mentagrophytes type VII (TMVII).

TMVII causes round rashes on the arms, buttocks, trunk, genitals, and legs. It is spread the same way as other ringworm infections. Unlike other types of ringworm, however, this one is primarily associated with sexual activity. So far most cases have been in men who have sex with men.

The largest cluster of cases has been in Minnesota. Public health experts in that state thanked clinicians for recognizing infections early and calling the health department immediately. TMVII is often mistaken for sexually transmitted infections (STIs) or other skin conditions like eczema.

Guidance on Diagnosis of TMVII

Now, the Centers for Disease Control and Prevention (CDC) is asking clinicians across the to pay close attention to possible infections. In a letter to clinicians, the CDC says that health care providers should consider TMVII as a possible diagnosis when patients have lesions on or near the genitals, groin, buttocks, or perineum (the area between the genitals and the anus). They should also consider it when patients have lesions on their face, beard or in other places with hair.

The letter suggests that clinicians take a detailed history to help them diagnose TMVII including asking questions about sexual exposure, recent travel, and whether they’ve used an over-the-counter creams or ointments. The letter also explains the preferred diagnostic tests and the best treatment regimen. It suggests that if clinician strongly suspect TMVII, they start treatment with an oral antifungal drug right away and continue to follow up. Treatment can take 6–12 weeks or longer before the lesions have fully resolved.

Clinicians should contact their health department for help with testing, reporting, and clinical management if needed. If a health department suspects an outbreak, they should reach out to the CDC directly via email. They can also get help with testing and treatment issues from the CDC via email.

How to Prevent TMVII

These recommendations are for clinicians, but there are things we can all do to stop the spread of TMVII. If you have a rash, consider it very contagious. Seek treatment as soon as possible and avoid skin-to-skin contact, including sex while lesions are present. It also a good idea to avoid personal items such as towels, bedding, clothing, razors, or sex toys.