Prolonged treatment of dermatophytosis caused by Trichophyton indotinea with terbinafine or itraconazole impacts better outcomes irrespective of mutation in the squalene epoxidase gene

Background Over the past decades, the increasing incidence of recurrent dermatophytosis associated with terbinafine‐resistant Trichophyton has posed a serious challenge in management of dermatophytosis. Independent reports of failure of treatment and high minimum inhibitory concentrations (MIC) of antifungals are available, but data correlating MIC and clinical outcomes is still sparse. Therefore, the present study was conducted to evaluate the outcomes of systemic treatment of dermatophytosis and its correlation with MIC of the etiological agents isolated from such patients. Methods Retrospective analysis of 587 consecutive patients with dermatophytosis was done from March 2017 to March 2019. Demographic and clinical details of the patients were noted, along with the results of direct microscopy and fungal culture. The isolates were identified by sequencing the internal transcribed spacer region of rDNA. Antifungal susceptibility testing was performed following the CLSI M38 protocol. Mutation in the squalene epoxidase (SE) gene was detected by DNA sequencing and ARMS‐PCR. Based on the culture‐positivity and prescribed systemic antifungal, patients were categorised into Group I culture‐positive cases treated with systemic terbinafine and Group II culture‐positive cases treated with systemic itraconazole, each for a total period of 12 weeks. Results In the present study, 477 (81.39%) were culture‐positive; however, 12 weeks follow‐up was available for 294 patients (Group I‐157 and Group II‐137) who were included for statistical analysis. In both groups [Group I‐37/63 (51.4%) and Group II‐14/54 (58.3%)], a better cure rate was observed if the initiation of therapy was performed within