Health care providers are being urged to stay vigilant for new and highly contagious forms of ringworm and jock itch, which are emerging as potential public health threats, according to a recent report from NYU Langone Health and the New York State Department of Health.
NYU Langone Health experts documented the first U.S. case of a sexually transmitted fungal infection that can take months to treat. Additionally, they described the largest group of U.S. patients with a similar therapy-resistant fungal strain.
Both fungal species cause tinea, which easily spreads on the face, limbs, groin, and feet. The tinea in these reports can appear different from the usual circular ringworm lesions, resembling eczema and potentially delaying proper treatment.
The report, published in JAMA Dermatology, detailed a man in his 30s who developed tinea on his penis, buttocks, and limbs after traveling to England, Greece, and California. Genetic tests identified the infection as Trichophyton mentagrophytes type VII (TMVII), a sexually transmitted ringworm increasingly diagnosed in Europe. The patient had multiple male partners during his travels, though none reported similar infections.
“Health care 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,” said study lead author Dr. Avrom Caplan in a statement.
“Since patients are often reluctant to discuss genital problems, physicians need to directly ask about rashes around the groin and buttocks, especially for those who are sexually active, have recently traveled abroad, and report itchy areas elsewhere on the body,” added senior author Dr. John Zampella.
TMVII infections, while difficult to treat, appeared to respond to standard antifungal therapies like terbinafine, though treatment can take months to clear up.
The report also described Trichophyton indotineae (T. indotineae), a strain widespread in India and now found globally. The infection, first confirmed in the U.S. last year, causes similar rashes but often resists terbinafine treatment.
When treated with another antifungal, itraconazole, some patients showed improvement. However, Caplan noted that itraconazole, while effective, can interfere with many medications and cause side effects, making it challenging to use long-term.
“These findings provide new insights into how some of the fungal skin infections spreading from South Asia can evade our standard therapies,” said Caplan. “Beyond learning to recognize their misleading signs, physicians will need to ensure their treatment addresses each patient’s quality-of-life needs.”
Caplan plans to collaborate with fungi experts nationwide and internationally to expand research efforts and track emerging cases.
The researchers advised dermatologists to be alert for signs of TMVII and T. indotineae, noting that U.S. rates remain low.
Full conflict of interest disclosures can be found in the observation.