Clinico-etiological Study of Tinea Corporis: Emergence of Trichophyton mentagrophytes

Background: Tinea corporis is a superficial fungal infection of the glabrous skin of the trunk and extremities caused by closely related organisms of the three genera – Trichophyton, Microsporum, and Epidermophyton, collectively known as dermatophytes. The prevalence of the different species varies according to geographic and climatic regions. Trichophyton rubrum has been reported from various worldwide (up to 80%) and Indian studies (up to 88%) as the most common causative organism of tinea corporis. Aim: The aim of the study was to study the clinico-etiological profile of tinea corporis in a tertiary care center. Materials and Methods: A total of 74 patients clinically diagnosed with tinea corporis fulfilling the inclusion criteria were recruited into the study. A detailed clinical history was obtained, and clinical examination was done and documented. Scrapings from the active margins of the skin lesions were taken for potassium hydroxide (KOH) mount and fungal culture on Saboraud’s dextrose agar. Results: KOH microscopy was positive in 91.9% of patients. The sensitivity of KOH microscopy in the study was 94.2% and specificity was 40% with a positive predictive value of 95.6% and a negative predictive value of 33.3%. Fungal growth was observed in 74.3% of the samples cultured. Trichophyton mentagrophytes was the most common dermatophyte isolated (64%) followed by Trichophyton tonsurans (20%) and T. rubrum (12%). Conclusion: T. rubrum only accounted for 12% of cases in this study. T. mentagrophytes was the most common pathogen isolated which has not been previously reported from our geographical location, and only very few reports from other parts of the world. The emergence of this organism warrants a renewed look into the antifungal susceptibility patterns for combating this common superficial fungal infection efficiently.