The correct answer is C. Initiate oral itraconazole. 

Trichophyton indotineae has emerged as a novel dermatophyte species associated with recalcitrant infections. While T. indotineae is most prevalent in South Asia and the UK, it has now spread to many parts of the world and is rapidly becoming a global health concern. This pathogen exhibits a high rate of mutations in the squalene epoxidase (SQLE) gene, leading to reduced susceptibility to terbinafine. Consequently, patients often do not respond to standard terbinafine treatment durations. Similarly, fluconazole has shown limited in vitro and clinical activity against this species. In contrast, T. indotineae remains largely susceptible to itraconazole, although prolonged treatment durations may be required to achieve cure. Therefore, initiating itraconazole therapy is the recommended next step. 

Wrong answers:
Initiate topical corticosteroids
Topical steroids exacerbate tinea infections, masking inflammation while allowing fungal overgrowth. Steroid misuse is a major contributor to widespread dermatophyte resistance

Initiate topical ketoconazole
Topical ketoconazole may help for mild cases but is insufficient for widespread or recalcitrant infections. The patient has failed systemic therapy, making topical treatment inadequate.

Initiate voriconazole
Voriconazole is not a first-line agent for dermatophytosis. It is primarily used for invasive fungal infections (e.g., aspergillosis), not superficial dermatophyte infections. Itraconazole is preferred due to its better activity against dermatophytes, more favorable side effect profile, and lower cost.

Initiate posaconazole
There are currently only 2 reports of successful treatment of tinea corporis with posaconazole.  Itraconazole remains more appropriate treatment option.

Initiate biologic therapy
Biologics are used for psoriasis and autoimmune conditions, not fungal infections.  The photo shown in addition to positive KOH findings supports diagnosis of dermatophytosis.

References:

Ramesh V, Kindo AJ, Ayyanar P, et al. Clinico-mycological and therapeutic updates on cutaneous dermatophytic infections in the era of Trichophyton indotineae. J Am Acad Dermatol. 2024;92(3):511-520. doi:10.1016/j.jaad.2023.09.012.

Brought to you by our brand partner