Simultaneous dermatophytosis and keratomycosis caused by Trichophyton interdigitale infection: a case report and literature review

BACKGROUND: Dermatophytosis is a fungal infectious disease caused by dermatophytes, which produce protease and keratinase to digest keratin, leading to the colonization, invasion, and infection of the stratum corneum of the skin, hair shafts, and nails. Trichophyton interdigitale belongs to Trichophyton mentagrophytes complex, which is the common pathogen causing dermatophytosis. Fungal keratitis, also called keratomycosis, is an infectious disease of cornea. CASE PRESENTATION: Here, we report a case of simultaneous dermatophytosis and keratomycosis caused by Trichophyton interdigitale. A 67-year-old man presented with extensive erythema all over the body since 4 years ago, fungal infection of left eye for 2 years, and loss of vision in the eye. These symptoms had become aggravated in the last month. Dermatological examinations showed extensive erythematous plaques with clear borders and scales, scattered red papules with ulceration, and scabs throughout the body. Onychomycosis was observed on the nails of left hand, conjunctival infection with secretion and loss of vision were noted in left eye. Hyaline septate hyphae were observed under direct microscopic examination, fungal culture and internal transcribed spacer sequencing revealed T. interdigitale. Histopathological examination suggested infectious granuloma. A diagnosis of dermatophytosis and keratomycosis caused by T. interdigitale with loss of vision in left eye was made. The patient was treated with luliconazole cream (two applications per day) and itraconazole (100 mg, BID, PO). Complete clinical remission was achieved after 1 month. Subsequently, the patient underwent left eye enucleation in the ophthalmology department. CONCLUSIONS: In the present study, we reported a case of simultaneous dermatophytosis and keratomycosis caused by T. interdigitale, and reviewed the literature on corneal infection caused by Trichophyton. A total of 10 articles with 45 patients were published between 1973 and 2018. The pathogen of 27 patient were identified to species level. There were T. schoenleinii (17), T. mentagrophytes (4), T. verrucosum (3), T. rubrum (1), T. erinacei (1), and T. interdigitale (1). Five patients had corneal trauma, one had contact lens use history. Direct microscopic examination, fungal culture, and analysis of physiological characteristics were the main methods of identification. Early diagnosis and prompt treatment may help improve the management and outcomes.