Track: Case Reports

Abstract:

A 47-year-old male refugee from Afghanistan presented with a five-month history of a pruritic rash. Physical exam demonstrated scaly papules and plaques with annular borders and central clearing involving the forearms, thighs, buttocks, and groin. He had failed multiple therapies, including topical miconazole, clotrimazole, and terbinafine, as well as oral terbinafine and itraconazole, prescribed empirically for tinea corporis. A punch biopsy of the groin revealed PAS-positive hyphae in the stratum corneum. Fungal culture initially isolated Trichophyton mentagrophytes, however due to high clinical suspicion, the specimen was sent to a reference lab for further evaluation. Trichophyton indotineae was then identified as the true causative pathogen and antifungal susceptibilities demonstrated terbinafine resistance with an MIC of >2 µg/mL and an MIC of 0.5 for voriconazole. The patient was treated with oral voriconazole and topical ciclopirox twice daily for a 12-week course with complete resolution. Trichophyton indotineae represents an emerging dermatophyte species associated with terbinafine-resistant tinea, with highest prevalence in South Asia. Resistance has been linked to sqle gene point mutations impacting terbinafine’s antifungal target, squalene epoxidase. Itraconazole is often considered first-line therapy in refractory cases; however, treatment failure has been reported. This case demonstrates the efficacy of voriconazole as an alternative agent. Here we describe a confirmed case of T. indotineae presenting as diffuse, treatment-resistant tinea corporis with resolution following voriconazole and ciclopirox therapy. This case highlights the need to consider T. indotineae in cases of refractory dermatophytosis and underscores the utility of biopsy, fungal culture, and antifungal susceptibilities to guide therapeutic management.

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Cameron Brown