This is a case report of a 15-year-old girl, who developed kerion Celsi on the vulva after contact with a pet rodent. The skin was extremely painful, highly red, severely inflamed and oozing, mimicking a bacterial abscess. The patient's general condition was barely affected. PCR identified Trichophyton mentagrophytes, successfully treated with terbinafin 250 mg for 12 weeks. The majority of incidents in 11 published cases were caused by T. mentagrophytes, sensitive to terbinafin. Knowledge of this rare inflammatory dermatophytosis may cause the surgeon to abstain from surgery and to "keep calm and kerion".