5 Things to Know About the New and Highly Contagious Fungal STI

The first US case was reported in June.

July 26, 2024

Illustration of red dots on a blue background to portray an STI

You probably don’t need one more thing to worry about, but a rare, ringworm-like fungus that can be sexually transmitted has been spotted in the US. A 30-something New York City man who’d recently traveled to England, Greece, and California went to the doctor with uncomfortable, circular rashes on his penis, butt, limbs, and back. After running a few tests earlier this year, researchers figured out it was caused by Trichophyton mentagrophytes ITS genotype VII, or TMVII for short, according to a case report published in June in JAMA Dermatology.

Dermatologists have had this super contagious fungus on their radar for some time now. There have been reports of TMVII in Southeast Asia and Europe, with 13 known cases in France in 2023. Like ringworm and jock itch, TMVII can cause a scaly red rash. While those more common fungal infections can be transmitted through skin-to-skin contact or from touching infected objects like used towels or sheets, experts say TMVII behaves a little differently.

“It’s problematic because of how it seems to spread, which appears to be through sexual contact,” Avrom Caplan, MD, lead author of the report and assistant professor of dermatology at NYU Grossman School of Medicine, tells SELF. Twelve of the 13 infections in France last year were among men who have sex with men, and the patient in the JAMA Dermatology report said he’d also had male sexual partners during his trip.

This is a relatively new STI, and experts still have a lot to learn when it comes to TMVII and the best ways to manage it. But here are a few things that are important to know about this very contagious (though luckily still rare) fungus right now.

1. It’s in the same family as ringworm.

Ringworm, jock itch, and athlete’s foot are all caused by fungi called dermatophytes that live on your skin, hair, or nails (lovely, right?). A “tinea” rash—it’s red, scaly, itchy, and can be ring-shaped—is a textbook sign of dermatophyte infection. These rashes typically crop up in moist areas on a person’s limbs or body (when it’s considered ringworm), scalp, groin (a.k.a. jock itch), feet (better known as athlete’s foot), or nails. For the record, ringworm has nothing to do with actual worms and gets its name from the rash’s shape. These germs can be picked up from casual contact with other people; pets, like a dog or cat; or public locker rooms or pool areas. Up until recently, these types of infections weren’t thought to be sexually transmitted.

Enter TMVII: Unlike other members of the tinea family tree, “the lesions appear on genital skin, which isn’t typical,” Dr. Caplan says. Of course, it’s worrying enough that this fungus can now spread via sex. But an additional concern, according to Dr. Caplan, is that because TMVII is sexually transmitted, people might feel anxious and stressed about stigma—so they may wait longer to bring up their symptoms with a doctor as a result. “That can lead to impaired quality of life and potential for further spread.”

2. TMVII can be mistaken for eczema or something else.

What experts have seen so far in people with TMVII suggests intense itching is a main symptom here. But doctors are not used to seeing these types of infections on your butt or genitals, so they might mistake it for eczema or even psoriasis.

Some people with TMVII also develop really painful, inflamed sores that can become “superinfected,” as Dr. Caplan puts it, with pockets of pus that may lead to scarring. “This doesn't happen for all patients, but it can happen.” In the 2023 report, some of the men’s lesions were so inflamed, doctors thought they were bacterial infections at first. Making the right diagnosis even harder, it’s also possible to have TMVII on your genitals while still developing tinea rashes in other spots, Dr. Caplan says.

3. TMVII is still rare, but it can be hard to treat.

In general, tinea infections like ringworm, jock itch, and athlete’s foot “are not concerning,” says Dr. Caplan. Topical antifungals usually nip these infections in the bud, and since OTC treatments are available, you usually don’t need a prescription to clear them up.

TMVII is proving a little trickier. While the infection eventually seems to respond to treatment, “it can take many weeks,” according to Dr. Caplan. The man in the JAMA Dermatology case report was given antifungals that are commonly prescribed for tinea, and it still took more than four months and multiple rounds of meds to rid the infection from his body. And some of the men mentioned in the 2023 report needed prolonged antifungal treatment before they felt better, and a few required hospitalization.

Experts don’t yet know whether TMVII is truly a hard-to-treat fungus or if it’s stubbornly persistent because it took doctors so long to figure out what was causing the rashes in these early cases.

4. We don’t yet know exactly how TMVII is spreading.

Right now, experts believe the primary way TMVII is transmitted is through sexual skin-to-skin contact. But it’s definitely possible that this fungus is circulating in other ways, too. “Tinea in general spreads through skin-to-skin contact, animals, or environmental exposure,” says Dr. Caplan, “and that may also be true of TMVII.”

The cases of TMVII we’ve seen so far don’t suggest you need to be too concerned about catching it from animals, he says. (Only a few men in the French report had any contact with pets, though nearly all mentioned having sex before their symptoms developed.) But because we know other forms of ringworm can spread through infected objects, it’s a good idea to avoid sharing personal items like towels or sports equipment, and not walking barefoot in public bathrooms or spas. (Also, because, yuck.) If you’re around someone with confirmed TMVII, you’ll want to take extra precautions—avoiding sex until their doctor gives the all-clear and washing your bedding and clothes with high heat, for example.

As for condoms? They help protect against pregnancy and STIs in general, and it’s never a bad idea to use one. But as with other diseases that spread skin-to-skin (think genital herpes, syphilis), they aren’t 100% effective—a condom would need to fully cover the tinea rash to offer real protection, Dr. Caplan says, so it’s still very possible to get TMVII if you have sex with someone who has an active infection, even if a condom is involved.

5. It’s not something to panic about.

No question about it: A painful, sexually transmitted genital rash that takes months to get rid of sounds scary. But Dr. Caplan stresses that this condition is still rare, and, ultimately, treatable. “I don’t think we should be overly concerned,” he says.

The report, he tells us, was published to raise awareness about TMVII with the hope that if someone were to notice a strange new rash on their genitals, both they and their doctor might think to rule out a fungal infection. Because TMVII can resemble so many other conditions—eczema, psoriasis, a bacterial infection, another STI—it’s been frustratingly slow for some patients to get a diagnosis, and it’s possible that those delays allowed the condition to become more severe and harder to treat.

“We still have a lot to learn about TMVII,” says Dr. Caplan, adding that his team is working with leading experts like the American Academy of Dermatology to help derms better understand this condition in the future. And all this is a good reminder that any new skin irritation or rash is worth getting checked out by your doctor—no matter what it looks like or where it appears.