In the last few years, infections caused by dermatophytes along with a concomitant increase in the number of difficult to treat cases have increasingly been recognised, indicating that dermatophytosis remains a challenging public health problem. The majority of infections are caused by Trichophyton rubrum and Trichophyton mentagrophytes complex. Terbinafine, an allylamine antifungal used orally and topically is considered to be a first-line drug in the therapy of dermatophyte infections. Terbinafine resistance has been predominately attributed to point mutations in the squalene epoxidase (SQLE) target gene a key enzyme in the ergosterol biosynthetic pathway leading to single amino acid substitutions. Here, we report the largest series of 20 terbinafine-resistant Trichophyton interdigitale isolates obtained predominately from cases of tinea corporis/cruris in three hospitals in Delhi, India exhibiting elevated MICs (4 to ≥32 μg/mL) to terbinafine and all harbouring single-point mutations Leu393Phe or Phe397Leu in the SQLE gene. In 12 (60%) T. interdigitale isolates, the Phe397Leu substitution was observed, whereas in the remaining 8 (40%) isolates the substitution Leu393Phe was reported for the first time in T. interdigitale. Furthermore, 10 susceptible T. interdigitale isolates (0.125-2 μg/mL) had a wild-type genotype. Remarkably, considerably high terbinafine resistance rate of 32% was observed among 63 T. interdigitale isolates identified by sequencing of the internal transcribed spacer region. This high level of terbinafine resistance of Indian dermatophyte isolates is worrisome warranting antifungal susceptibility testing and mutation analysis for monitoring this emerging resistance.

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Telogen effluvium (TE) is one of the most common causes of diffuse nonscarring hair loss. In its acute form, it generates a lot of anxiety in the patient, which can be significantly allayed with a confident diagnosis. In its more chronic form, however, the hair loss may go unnoticed for long periods of time. Here in, the dermatologist's role in differentiating it from the more common patterned hair loss is significant. Differentiating TE from other causes of diffuse nonscarring hair loss can indeed be a daunting task and TE is often used as a waste basket diagnosis. A number of factors have been implicated in the causation of TE, however, clear evidence in their support is lacking. The role of stress as a causative factor as well as the result of hair loss needs to be adequately understood. This review aims at summarizing our current level of knowledge with respect to this very common cause of hair loss. An attempt is made to help the readers reliably differentiate TE from other causes of diffuse nonscarring hair loss. The possible causative factors, pathogenetic mechanisms, clinical presentation, and possible treatment options are discussed.

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