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- Presentation
Tackling Trichophyton indotineae: Emerging Global Dermatophyte Infection and Antifungal Resistance
Description
The session reviews Trichophyton indotineae, a recently described dermatophyte that has become a major global concern because of its rapid spread, frequent misidentification, and antifungal resistance. Dermatophytosis is a common superficial infection, but T. indotineae causes extensive, often recalcitrant plaques, usually in the groin or on the extremities, and commonly fails standard topical therapy and normal-dose terbinafine due to squalene epoxidase mutations. Itraconazole is often recommended after terbinafine failure, but it may require prolonged, high-dose treatment and relapses can occur. Accurate diagnosis usually requires molecular methods such as ITS sequencing, which are not widely available and have historically been confounded by poor databases and similarity to related species. The organism likely originated in South Asia, especially India, where it has become dominant in some studies, and it has now been reported in more than 40 countries, including the United States. It spreads mainly through close person-to-person contact, with family clusters common, though contaminated surfaces, shared clothing, and possibly animals may contribute. Risk factors include travel to endemic regions, close contact with infected individuals, hot humid environments, overcrowding, poor hygiene, and topical steroid or inappropriate antifungal use. The talk emphasizes that rising resistance, driven in part by misuse of over-the-counter combination creams and prior antifungal exposure, makes surveillance, stewardship, and increased clinical awareness essential for early recognition and containment.
View moreConclusions
- Trichophyton indotineae is an emerging dermatophyte that has rapidly spread from South Asia to many countries worldwide, including the United States.
- The organism is now a major cause of recalcitrant dermatophytosis and has displaced more traditional species such as T. rubrum in some settings.
- Routine clinical and morphological methods often misidentify T. indotineae, so molecular sequencing is usually needed for accurate diagnosis.
- Persistent or treatment-resistant tinea, especially with travel to endemic regions or close household contact, should raise suspicion for T. indotineae infection.
- Transmission appears to be mainly person-to-person, with family clusters common and environmental contamination and occasional animal reservoirs also possible.
- T. indotineae infections are often difficult to clear and may require prolonged treatment with itraconazole after terbinafine failure.
- Rising antifungal resistance, particularly terbinafine resistance, is the most important clinical challenge posed by this pathogen.
- Misuse of over-the-counter antifungals and steroid-containing combination creams likely contributes substantially to the emergence of resistance.
- Better surveillance, awareness, and antifungal stewardship are needed to limit further spread and improve early recognition and management.
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- References slide with ten academic citations on Trichophyton indotineae, dermatophytosis, terbinafine resistance, and related clinical studies.