Dermatologists and infectious disease specialists have warned that a drug-resistant ringworm fungus, Trichophyton indotineae, has been detected in 29 countries following a study documenting its rapid international spread. The pathogen resists terbinafine, the standard oral treatment for skin fungal infections.

The fungus causes widespread, intensely itchy skin lesions that often cover large areas of the body and fail to clear with conventional creams and pills. Researchers traced much of the spread to South Asia, where overuse of combination topical steroid-antifungal products has driven resistance, before cases appeared across Europe, North America and the Middle East.

The Centers for Disease Control and Prevention has confirmed cases in the United States, while the European Centre for Disease Prevention and Control has flagged rising diagnoses in Germany and other member states. Specialists said many infections are misdiagnosed as eczema, delaying appropriate care and allowing further transmission within households.

Researchers at the CDC's mycotic diseases branch called for laboratory confirmation of stubborn ringworm cases and restraint in prescribing broad topical steroid mixtures. They warned that itraconazole, an alternative antifungal, requires longer courses and closer monitoring, complicating treatment in low-resource settings.

The International League of Dermatological Societies has urged clinicians to report suspected resistant cases to national surveillance systems. The World Health Organization, which lists antifungal resistance among priority health threats, said the spread underscored gaps in global fungal disease monitoring.