RESUMO
INTRODUCTION: Tinea capitis, a common scalp infection primarily affecting children, is caused by keratinophilic dermatophytic fungi, notably Microsporum and Trichophyton species. Microsporum canis, primarily transmitted from cats and dogs to humans, is rarely reported in non-endemic regions like India. We report a cases involving three family members from Delhi, India, diagnosed with tinea capitis caused by Microsporum canis. The index case, a five-year-old boy, contracted the infection through contact with a cat, while his younger brother and sister acquired it through human-to-human transmission within the family. METHODS: Clinical examination, microscopic analysis, and molecular identification techniques confirmed the diagnosis. Antifungal susceptibility testing revealed sensitivity to itraconazole and terbinafine but resistance to griseofulvin. RESULTS: Treatment with oral terbinafine and topical ketoconazole cream led to successful outcomes for all three patients. Molecular typing confirmed clonality of the isolates, indicating human-to-human transmission. CONCLUSION: This case study underscores the significance of considering atypical sources of infection and human-to-human transmission in the diagnosis and management of tinea capitis caused by Microsporum canis in non-endemic regions. It emphasizes the necessity of thorough contact history assessment and appropriate antifungal therapy for effective control of the infection.