Spread of Antifungal-Resistant Trichophyton indotineae, United Kingdom, 2017–2024

Author: mycolabadmin
1/1/2025
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Summary

A highly resistant fungal infection called Trichophyton indotineae is rapidly spreading throughout the United Kingdom. Originally from southern Asia, this fungus causes difficult-to-treat skin infections, particularly in the groin area, and resists standard antifungal medications in about three-quarters of cases. Since 2023, cases have spread from London to other parts of the UK and Ireland, and experts predict it will soon become the leading cause of ringworm in the country.

Background

Trichophyton indotineae is an emergent dermatophyte causing superficial skin infections that started in southern Asia in 2014. The fungus exhibits high rates of terbinafine resistance and spreads easily from person to person. Cases have been reported worldwide including Europe, Canada, and the United States, with evidence of acquisition and transmission outside endemic areas.

Objective

To describe all cases of T. indotineae identified at the UK National Mycology Reference Laboratory during a 7-year period from August 2017 to July 2024 and characterize their clinical, epidemiologic, and antifungal susceptibility profiles.

Results

157 cases of T. indotineae were identified, with 84.7% of patients linked to endemic areas. The groin and buttocks were affected in 42.7% of cases, and 74.2% of isolates showed in vitro terbinafine resistance. T. indotineae prevalence increased from 2% in 2018 to 38% of all dermatophyte isolates in 2024, with cases spreading from London to 27 additional cities.

Conclusion

T. indotineae was introduced into the United Kingdom from endemic areas and is spreading substantially. Current trends suggest it will rapidly become the predominant cause of tinea corporis in the United Kingdom, and clinicians should recognize this fungus accordingly.

Published in:Emerging Infectious Diseases,
Study Type:Descriptive Epidemiological Study,
Source: 10.3201/eid3101.240923