LAUSR

Dear Editor, Tinea auricularis is an uncommon and neglected dermatophytosis, which can easily be misdiagnosed as eczema and lead to topical steroid treatment, which can then modify the clinical appearance of the dermatophytosis, mimicking other diseases. Our previous study showed that trichoscopy under standard, polarized and ultraviolet (UV) light can highlight fungal invasion of vellus hair in tinea vellus. We report a case of childhood tinea auricularis, diagnosed rapidly by combination dermoscopy. A 4-year-old boy presented with an 8-month history of persistent erythema with itching on the outer edge of his left ear, which was unresponsive to topical steroids. Physical examination revealed multiple red papules on the left ear (Fig. 1a). Dermoscopy (SKIARY sk-3; Beijing Xiangzhen Technology Co. Ltd, Beijing, China) showed curly and coiled vellus hairs, with bright-white fluorescence under UV dermoscopy indicating invasion of vellus hairs (Fig. 1b). Direct fluorescence microscopy showed ectothrix spores and hyphae of vellus hairs (Fig. 2). Microsporum canis was isolated in culture on Sabouraud agar. Under a diagnosis of pet-related tinea auricularis, we started systemic antifungal treatments with itraconazole for 4 weeks. The patient recovered, and there was no recurrence after follow-up for half a year. Tinea auricularis is uncommon and easily misdiagnosed; however, the notable observation is the sole involvement of the ear. This is because the structure of the ear is full of convexities and concavities, which retain sweat, and as it is frequently subject to friction, this makes it more susceptible to fungus infection. In conclusion, UV dermoscopy is a rapid and noninvasive diagnosis tool for dermatophytosis caused by M. canis, including the uncommon tinea auricularis, facilitating prompt systemic antifungal treatment.