Terbinafine-resistant Trichophyton mentagrophytes type VII: An emerging sexually transmitted dermatophytosis

Abstract

Sexually transmitted dermatophytosis caused by Trichophyton mentagrophytes genotype VII (TMVII) has recently emerged as a novel clinical entity, particularly within sexual networks. This pathogen is characterized by inflammatory genital lesions, diagnostic challenges, and increasing antifungal resistance. We report a case of genital dermatophytosis caused by terbinafine-resistant TMVII in a heterosexual woman following sexual exposure abroad. A 35-year-old otherwise healthy woman presented with a 3-week history of rapidly progressive, intensely pruritic genital lesions unresponsive to topical antifungal therapy. Clinical examination revealed well-demarcated annular erythematous plaques with central clearing and an active scaly border confined to the pubic and inguinal regions. Direct microscopic examination demonstrated fungal hyphae, and fungal culture identified Trichophyton mentagrophytes. Molecular analysis by PCR sequencing confirmed genotype VII. The patient denied animal contact or fomite exposure but reported unprotected sexual intercourse during recent travel to Turkey. Screening for sexually transmitted infections, including HIV, hepatitis B, and syphilis, was negative. Oral terbinafine therapy (250 mg/day for 4 weeks) was ineffective. Antifungal susceptibility testing confirmed biological resistance to terbinafine. Treatment was switched to oral itraconazole (100 mg/day for 4 weeks), resulting in complete clinical resolution without relapse. This case illustrates an emerging sexually transmitted dermatophytosis due to terbinafine-resistant TMVII. To our knowledge, no previous cases linked to travel to Turkey have been reported. The report highlights the importance of considering TMVII in patients presenting with inflammatory genital dermatophytosis, particularly when lesions are refractory to standard antifungal therapy. Early recognition, molecular confirmation, appropriate treatment, and partner management are essential to prevent further transmission of this emerging pathogen.