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The first case of a sexually transmitted form of ringworm has been reported in the United States. Bevan Goldswain/Getty Images
  • Trichophyton mentagrophytes is a fungus that causes ringworm in people and in cats, dogs and other pets.
  • A subtype of this fungus can be acquired through sexual contact, according to the CDC.
  • In some parts of the world, this fungus is drug-resistant, but in the US, it still responds well to common antifungals.

A sexually transmitted ringworm caused by a certain fungus has been reported for the first time in the United States.

“Healthcare providers should be aware that Trichophyton mentagrophytes type VII is the latest in a group of severe skin infections to have now reached the United States,” study author Avrom Caplan, MD, a dermatologist and assistant professor in the Ronald O. Perelman Department of Dermatology at NYU Grossman School of Medicine, said in a release.

T. mentagrophytes is a common type of fungus that can cause ringworm in people, as well as in cats, dogs and other pets.

“It is one of the most common causes of ringworm, a contagious fungal infection of the skin, hair and nails,” said Bindu Balani, MD, an infectious disease specialist with Hackensack University Medical Center, who was not involved in the new research.

It can also cause athlete’s foot, jock itch, and barber’s itch, she told Healthline.

T. mentagrophytes genotype VII is a specific type of this fungus that can be sexually transmitted, according to the Centers for Disease Control and Prevention.

Cases of T. mentagrophytes genotype VII have been reported in other parts of the world, including in Southeast Asia and Europe.

In a report released June 5 in JAMA Dermatology, Caplan and his colleagues describe the first documented case in the United States of this sexually transmitted fungus.

The case involved a man in his 30s from New York City who developed an itchy rash on his genitals, buttocks, and limbs after returning from a trip to England, Greece, and California.

The man “reported multiple male sexual partners while traveling, none with a similar infection, and visited a sauna 2 months prior to developing skin lesions,” the researchers write.

Genetic tests confirmed that the fungus causing the rash was T. mentagrophytes genotype VII.

The man was treated for 4 weeks with the antifungal medication fluconazole with no response. He was then treated with the antifungals terbinafine and itraconazole, both of which improved his symptoms.

Dr. Aniruddha Hazra, MD, an infectious diseases physician and associate professor of medicine at UChicago Medicine, who was not involved in the new research, said this type of rash may look like jock itch or ringworm, typically a patch or patches of dry, scaly skin.

The researchers said this type of infection may also cause a rash that looks more like an eczema flare than a ringworm infection with the characteristic circular pattern on the skin.

While the infection is not fatal, it can cause permanent scarring, they added.

Balani said fungal infections of the skin are generally treated with topical antifungal creams, lotions or gels, although oral antifungal medications may be needed for more severe infections or for infections that affect the hair or nails.

However, she pointed out that “in some cases, Trichophyton mentagrophytes type VII can be resistant to standard antifungal treatments.”

Even though T. mentagrophytes genotype VII can be difficult to treat and the infection may take months to clear up, Hazra said in the United States, this fungus still responds well to treatment.

“People who are concerned about STIs should be aware of this, especially when thinking about a rash that may not be improving,” he said, “but our usual antifungals are readily effective against it.”

Balani agrees that people shouldn’t be overly concerned about this infection: “With just one known case [in the United States], there’s no evidence this is widespread, or that this is something the public needs to worry about,” she said.

However, “if people are having itchy eruptions in areas like the groin, and it’s not improving or is resistant to the usual fungal treatments, they may want to see a healthcare professional,” she said.

People may also want to see a healthcare professional if the rash appears in the weeks following sexual activity, or after travel to Southeast Asia or Europe, where this fungus has been increasingly diagnosed, she said.

The only way to diagnose T. mentagrophytes genotype VII is through fungal sampling/scraping, she said.

“If diagnosed with this particular fungus, I also recommend getting screened for other sexually transmitted infections,” she said.

In addition, you should seek medical care if “you have a rash accompanied by symptoms affecting the entire body, rather than just the skin, such as a fever, muscle aches, nausea & vomiting, etc.,” Balani said.

Balani offered the following general tips for dealing with fungal infections of the skin:

  • Keep the affected area clean and dry to prevent the fungus from growing.
  • Wash your hands often, especially after touching animals or soil.
  • Avoid sharing personal items, including towels, combs, and brushes.
  • Wear shoes in public places. This will help protect your feet from infection.

In a recent case study, researchers describe the first reported case of a sexually transmitted ringworm caused by a certain fungus, Trichophyton mentagrophytes type VII.

The case occurred in a man from New York City who traveled to England, Greece and California. After he returned home, he developed a rash on his genitals, buttocks, and limbs.

Cases of this fungus have occurred in Southeast Asia and Europe, with some reports of drug resistance. However, in the United States, this fungus still responds well to frontline antifungal medications.