Adult Kerion Caused by Trichophyton tonsurans

Adult tinea capitis, especially kerion, caused by Trichophyton tonsurans is relatively rare in China. Here, we report a case caused by the agent in an old woman with normal immune function. Fungal microscopic examination and culture were positive. The isolate was further identified as Trichophyton tonsurans by internal transcribed spacer (ITS) sequencing. Skin biopsy and histopathological examination suggested diffuse inflammatory cell infiltration in the dermis and subcutaneous tissue. Notably, fungal spores were observed within the dermis by Periodic acid-Schiff (PAS) staining. After eight weeks of treatment with oral griseofulvin and topical luliconazole, the patient's abscess subsided, hair regrowth occurred without scarring, and the mycologic examination returned negative.