Coexistence of Malassezia Species and Microsporum canis in the Lesions of Adult with Tinea Capitis.

Tinea capitis, primarily caused by dermatophytes such as Trichophyton and Microsporum species, is a superficial fungal infection affecting the scalp and hair, commonly observed in prepubertal children but rare in adults. Here we report a unique case of an adult female with tinea capitis presenting as diffused alopecia and erythema inflammation on the scalp's apex, mimicking seborrheic dermatitis. Examination of the hair and scalp using fluorescence microscopy and fungal culture identified the presence of hyphae from Malassezia globosa, Malassezia furfur and Microsporum canis. The patient underwent with oral antifungal treatment for 3 months, resulting in the resolution of the rash and subsequent hair regrowth, with no recurrence during 6-month follow-up. In vitro co-culture experiments of Microsporum canis and Malassezia (both Malassezia globose and Malassezia furfur) revealed that Malassezia appears to facilitate Microsporum canis growth, while the reverse was not observed. This data suggests that Malassezia's use of long-chain fatty acids by might reduce its antibacterial effect, potentially aiding adult tinea capitis development caused by Microsporum canis.