Supplementary Material for: Kerion Celsi in elderly female, caused by Trichophyton rubrum - Case Report

Kerion celsi is a form of deep inflammatory tinea capitis, presenting with suppurative, tender plaque, often with pustules and purulent drainage. Tinea capitis is believed to be increasing in incidence worldwide. It mostly affects children and is most commonly caused by zoophilic dermatophytes. Globally, the most common transmission route is anthropophilic. Here we present a case of a 92-year-old female without associated chronic diseases, who lived alone in urban apartment and developed kerion in addition to having chronic untreated toenail onychomycosis and tinea pedis. Using PCR, we confirmed Trichophyton rubrum as the causative pathogen of toenail onychomycosis and kerion, suspecting autoinoculation pattern of transmission of dermatophytes from feet to the scalp. With the literature review, we discovered sporadic case reports, linking toenail onychomycosis caused by Trichophyton rubrum to development of kerion and kerion-like lesions in adult patients. Our case report: 1) adds another interesting case to series of rare cases of Trichophyton rubrum causing kerion in elderly, suspecting it is in fact more common than thought, 2) highlights PCR as a useful diagnostic tool for fast diagnosis and implementation of appropriate antifungal therapy, 3) recognizes a pattern of autoinoculation transmission of Trichophyton rubrum from toenail onychomycosis to the scalp, causing kerion celsi in elderly.