Two new and highly contagious fungal infections that cause difficult-to-treat skin rashes are prompting experts to alert healthcare providers. The infections, known as Trichophyton mentagrophytes type VII (TMVII) and Trichophyton indotineae, can be mistaken for eczema, potentially leading to months without receiving the proper treatment.
In a study published in JAMA Dermatology on June 5, researchers at NYU Langone Health documented the first U.S. case of the sexually transmitted TMVII, a form of ringworm increasingly diagnosed in Europe, particularly among men who have sex with men. The patient, a man in his 30s, developed rashes on his genitals and limbs after travelling abroad and having multiple male sexual partners.
"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," said the study's lead author, Dr. Avrom S. Caplan, a dermatologist at NYU Grossman School of Medicine in a news release.
In a separate study in May, NYU Langone physicians and the New York State Department of Health described the largest U.S. group of patients with T. indotineae, a fungal strain resistant to standard antifungal therapies such as terbinafine. Genetic analysis revealed mutations that prevent terbinafine from effectively targeting the fungus.
While TMVII infections appear responsive to terbinafine, T. indotineae often requires alternative treatments such as itraconazole, which can cause side effects. According to the report, three of seven patients treated with itraconazole recovered fully, and two improved.
"These findings offer new insight into how some of the fungal skin infections spreading from South Asia can evade our go-to therapies," Dr. Caplan said. "Physicians will need to ensure their treatment addresses each patient's quality of life needs."
Both fungi cause highly contagious tinea infections such as ringworm, jock itch, and athlete's foot, which can spread on the face, limbs, groin, and feet. However, the rashes may not resemble the typical ringworm pattern, increasing the risk of misdiagnosis. The researchers caution that dermatologists should watch for signs of TMVII and T. indotineae among patients.