Resistant Trichophyton indotineae Dermatophytosis—An Emerging Pandemic, Now in the US

Abstract

Fungus is finding 15 minutes of fame.A variant Ophiocordyceps unilateralis, a real-life fungus, took a fictional star turn in 2023 as the culprit behind a civilization-threatening zombie pandemic in HBO's blockbuster series, The Last of Us. Increasing infections with Candida auris-a fungus resistant to many antifungal medicines, often acquired in health care settings, and frequently fatal-have prompted the US Centers for Disease Control and Prevention (CDC) to label that fungus a "serious global health threat." 1 Psilocybin, the psychoactive substance found in magic mushrooms, is gaining attention for its potential to treat depression and other psychiatric conditions. 2 And now: Trichophyton indotineae. This dermatophyte is, almost literally, on steroids; experts have linked its emergence to inappropriate use of combination topical products containing antifungals and high-potenc y corticosteroids. [3][4][5] First described as a unique species in the past decade, 6 T indotineae (previously called Trichophyton mentagrophytes genotype VIII) has caused outbreaks of tinea-often extensive, pruritic, and frequently resistant to first-line antifungalsprimarily in South Asia but also in Europe, Canada, Australia, and Asia. 4,5 The first 3 cases of T indotineae dermatophytosis in the US were reported in 2023, 7,8 and a fourth casepossibly sexually transmitted-was reported in 2024. 9 A case series in this issue of JAMA Dermatology describes 11 more T indotineae infections in New York City from May 2022 to May 2023. 10 The case series included 5 female and 6 male patients, with a median (range) age of 39 (8-64) years. Only 1 was immunocompromised and had untreated lymphoma. Nine had traveled to Bangladesh within 2 years prior to rash onset; 4 of those patients also had contact with a family member or partner with T indotineae infection. One patient had neither traveled internationally nor had contact with an infected person, to their knowledge. Epidemiologic exposures were not available for 1 patient.All patients experienced widespread rash, most commonly involving the trunk, extremities, groin, and buttocks; 2 patients had facial involvement. Nine patients reported pruritus.Delays in diagnosis were substantial, with a median (range) of 10 (3-42) months. Prior to diagnosis, 6 patients were treated with topical corticosteroids, including 2 with combination antifungal-corticosteroid topicals. All patients unsuccessfully tried treatment with at least 1 topical antifungal medicine. Except for 1 patient who was initially treated with itraconazole, all patients were unsuccessfully treated with at least