New, Difficult-to-Treat Fungal Skin Infections Are Emerging, Clinicians Warn

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Experts are raising alarms about new and emerging fungal skin infections that are highly contagious and difficult to treat, though current US rates remain low.

Dermatologist and research administrator, Avrom Caplan, MD, and his team of experts at NYU Grossman School of Medicine, urge health care providers to be aware of these 2 new forms of ringworm or jock itch, known as Trichophyton mentagrophytes type VII (TMVII) and Trichophyton indotineae, or T. indotineae.

Their warnings are detailed in 2 of their recent reports.

The latest report, published in JAMA Dermatology, documents the initial US case of the sexually transmitted fungal infection TMVII that has been rising in Europe, particularly among men who have sex with men.¹

The second study, released in May in JAMA Dermatology, is by Caplan’s team and the New York State Department of Health. The study details that US T. indotineae cases are resistant to standard treatments.²

Both TMVII and T. indotineae cause tinea infections such as ringworm, jock itch and athlete’s foot, often misdiagnosed as eczema. Tinea genitalis/pubogenitalis, a rare dermatophytosis of the genital areas, is linked to the rise of T. indotineae; it has increased in India and is influenced by climate, hygiene and misuse of steroids.

European tinea genitalis cases are linked to TMVII, potentially spreading sexually.

In the first report in May, it details a man in his 30s who contracted TMVII after traveling to England, Greece, and California.

Genetic testing confirmed the infection, and the man in the study reported having multiple male sexual partners during his travels, none of which had similar skin issues.

John Zampella, MD, an associate professor in the Ronald O. Perelman Department of Dermatology at NYU and study senior author, said in the release that while infections caused by TMVII are difficult to treat and can take months to clear up, they so far appear to respond to standard antifungal therapies such as terbinafine.

Caplan stressed the importance of doctors asking patients directly about rashes, especially in people who are sexually active.

While TMVII infections generally respond to standard antifungal therapies, Caplan's other report reveals T. indotineae's resistance to terbinafine.

Based on the report, T. indotineae infections resist terbinafine because of genetic changes in specific areas of the fungus. These changes affect how terbinafine binds to the fungus, making it less effective.

However, another antifungal called itraconazole may still work, although it can have side effects.

Caplan plans to work with other experts to better understand these emerging infections.

References

1. Caplan AS, Sikora M, Strome A, et al. Potential sexual transmission of tinea pubogenitalis from TMVII. JAMA Dermatol. Published online June 05, 2024. doi:10.1001/jamadermatol.2024.1430
2. Caplan AS, Todd GC, Zhu Y, et al. Clinical course, antifungal susceptibility, and genomic sequencing of Trichophyton indotineae. JAMA Dermatol. Published online May 15, 2024. doi:10.1001/jamadermatol.2024.1126

[This article was originally published by our sister publication, Managed Healthcare Executive.]