Key TakeawaysNew York scientists announced the first U.S. case of a rare, sexually transmitted fungal infection last week.A related fungal species is also infecting a small number of people, causing genital and pubic rashes.That infection appears to be mostly resistant to the go-to anti-fungal medication, raising concerns about the increase in anti-fungal resistance worldwide.

Key Takeaways

New York scientists announced the first U.S. case of a rare, sexually transmitted fungal infection last week.A related fungal species is also infecting a small number of people, causing genital and pubic rashes.That infection appears to be mostly resistant to the go-to anti-fungal medication, raising concerns about the increase in anti-fungal resistance worldwide.

Two rare ringworm infections affecting the genital area are cropping up in the United States, according to reports published last month. This infection can potentially spread through sexual contact and may resist standard anti-fungal medications.

Last year, researchers in France published a study of 13 men with TMVII, 12 of whom had sex with men.The authors said the fungus seemed to spread through sex because of where the lesions appeared. In those cases, some patients may have acquired the infection locally, while others were likely exposed to TMVII after traveling to Southeast Asia and having contact with local sex workers.

“Fungal agents such as ringworm occur through any prolonged direct skin-to-skin contact, but also via towels, bed linen, and clothing. Therefore, several factors must be ruled out before a determination can be made that this case was solely a result of sexual activity,” said Cadence Acquaviva, a spokesperson for the New York Department of Health.

Another study examined 11 patients with a related fungal strain, calledTrichophyton indotineae.Both fungi seem to spread primarily through close skin contact, and standard antifungal treatments didn’t work for those patients.

Ringworm often presents as a neat, circular rash. However, in these cases, the infection can resemble lesions from eczema, making it challenging to diagnose, saidAvrom Caplan, MD, study lead author and assistant professor of dermatology at NYU Grossman School of Medicine.

So far, there are few confirmed cases of these fungal infections. The goal of publishing these reports, Caplan told Verywell, “is not to alarm anybody, but to alert primarily clinicians that if someone comes in with these lesions that are scaly or inflamed or itchy or painful around the pubic or genital region, don’t forget to think about [these fungi].”

WhatTrichophytonInfections Look Like

T. indotineaehas mostly been identified in India and Bangladesh but is now spreading globally. The first two confirmed cases in the U.S. were reported in New York state last year, but Caplan said earlier cases have likely flown under the radar.

The lesions from this fungus tend to be widespread across the face, body, and groin. They tend to be itchy and very inflamed.

Many people may be exposed toTrichophytonfungi and not develop an infection. Typically, immunocompromised patients are most at risk for developing ringworm. However, Caplan said most of the patients in his study are immunocompetent, but they have a lot of ringworm.

“It can be mistaken for eczema or psoriasis or other types of skin conditions, so sometimes there is a delay in getting the right diagnosis for patients, too,” he added.

It’s uncommon for a dermatophyte—a fungus that causes infections in the skin and nails—to spread through sexual contact, explainedMahmoud Ghannoum, PhD,a professor and Director of the Center for Medical Mycology at Case Western Reserve University, and one of the authors of another case study of possible sexual transmission ofT. indotineae.Fungal species likeCandida, which often lives in the vagina, can spread through skin-to-skin contact, but it doesn’t usually cause skin infection, he said.

Challenges With Treatment

Scientists in the mycology laboratory at the NY Health Department’s Wadsworth Center analyzed the genetic information of the fungi and tested how they would respond to different treatments.

TMVII,T. indotineae, and other superficial fungal infections can look very similar, and may only be differentiated through advanced testing, like DNA analysis.

The New York and European studies showed that people with TMVII could be treated with terbinafine, the standard oral anti-fungal medication. Those patients had to take the drug for longer than most people with ringworm require, but the infections finally cleared.

T. indotineae,on the other hand, appears to be resistant to terbinafine, even when taken for six weeks. A different oral antifungal treated the infection for most patients. However, that treatment comes with significant downsides, like interference with other drugs and side effects like nausea and diarrhea, which makes it a poor option for some people.

“[Terbinafine] is a drug that had been very good because we did not see much resistance to it. Now, lo and behold, we are seeing resistance,” Ghannoum said. “This is very big because people talk about bacterial resistance, but we do not have a lot of infections that are anti-fungal resistant.”

Testing Is Key to Detect and TreatTrichophytonInfections

When a patient presents with rashes that look like ringworm, a clinician may take a sample of the infection and send it to a lab for analysis.

“If you look at, say, a nail and you think there’s a fungal infection, there are many other diseases, such as cancer or bacterial infections, that look like the fungus. So you don’t know if it’s fungus or not. The only way to know is to do the test,” Ghannoum said.

Diagnosing the pathogen with a lab test is crucial for finding the right treatment. The lab will check how well different medications work to neutralize the fungal species.

TMVII andT. indotineaedon’t respond well to standard antifungal medications, which may be partly due to the rise of antifungal resistance worldwide. This is similar to antibacterial resistance, which occurs when the overuse and misuse of antibiotics allow “super bacteria” to develop that are immune to the existing medications.

“We are seeing some fungi that are what you call ‘pan-resistant,’ which means they’re resistant to all available antifungals. That’s why we need more [antifungals],” he said. “But at the same time, we also need to test against what we have. Of the four different classes we have, one of them may work, but how would you know which one without testing?”

If you are getting tested for aTrichophytoninfection, Ghannoum said you should “insist” that your doctor send a sample for lab analysis to ensure you receive the correct treatment.

The Centers for Disease Control and Prevention (CDC) is conducting a survey to see how many cases ofTrichophytoninfection there are in the U.S. But for now, Caplan said there’s no evidence that the two new fungal infections are widespread.

“There really should be no shame or anxiety about reaching out to a clinician and saying, ‘I’ve got this rash or this lesion that’s really just not getting better. Can someone take a look at it?’” Caplan said.

What This Means For YouVisit a health provider if you find red, scaly, inflamed, and/or painful rashes on your body. If they think you might have ringworm, consider asking for a lab test to verify that the infection is fungal and to identify the species that’s causing it. That could help ensure you get the most effective treatment.

What This Means For You

Visit a health provider if you find red, scaly, inflamed, and/or painful rashes on your body. If they think you might have ringworm, consider asking for a lab test to verify that the infection is fungal and to identify the species that’s causing it. That could help ensure you get the most effective treatment.

5 Sources

Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.

Caplan AS, Sikora M, Strome A, et al.Potential sexual transmission of tinea pubogenitalis from TMVII.JAMA Dermatol. Published online June 5, 2024. doi:10.1001/jamadermatol.2024.1430

Jabet A, Dellière S, Seang S, et al.Sexually transmittedTrichophyton mentagrophytesgenotype VII infection among men who have sex with men.Emerg Infect Dis. 2023;29(7):1411-1414. doi:10.3201/eid2907.230025

Caplan AS, Todd GC, Zhu Y, et al.Clinical course, antifungal susceptibility, and genomic sequencing ofTrichophyton indotineae.JAMA Dermatol. Published online May 15, 2024. doi:10.1001/jamadermatol.2024.1126

Spivack S, Gold JAW, Lockhart SR, et al.Potential sexual transmission of antifungal-resistantTrichophyton indotineae.Emerg Infect Dis. 2024;30(4):807-809. doi:10.3201/eid3004.240115

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