A Case of Kerion Celsi due to Trichophyton tonsurans.

The patient was a 13-year-old boy who was a member of the judo club at his junior high school. Approximately 1 week prior to his presentation, he developed multiple erythematous pilaris papules on his occipital area and was treated by a local doctor. The erythematous lesions expanded to 10 × 10 cm, showing granulation with drainage and strong spontaneous pain. At this point, he visited our hospital. He was diagnosed with kerion celsi due to Trichophyton tonsurans by fungal examination. The patient was treated with terbinafine (125 mg/day) for 6 weeks, and a brush test at 6 weeks was negative. All 18 members of the judo club, including this patient, were investigated; brush tests were positive in 4 cases, and one was positive for tinea corporis alone. The patient's family members parents were both negative. When an athlete is diagnosed with ringworm, T. tonsurans infection should be considered, and testing and treatment of family members and fellow athletes should be carried out to prevent the spread of infection.