Tinea incognito refers to dermatophyte infection with an atypical clinical presentation that have been modified by the previous treatment with steroid. Since tinea incognito has various manifestation rather than typical clinical presentations, the diagnosis of tinea incognito can be delayed or difficult. A 61-year-old man presented with ill-defined erythematous patches with telangiectasia which persisted on his face and neck for several months. The patient was first diagnosed as photosensitivity, and used topical steroid for 3 months. However, the lesion had not been improved. Therefore, potassium hydroxide (KOH) examination was performed on his peripheral neck lesion, and the result was positive. He also had onychomycosis for several years. Trichophyton rubrum was isolated with fungus culture and polymerase chain reaction (PCR). On the skin biopsy, hyphae were observed in the keratin layer. The patient was thus diagnosed with tinea incognito, and was prescribed oral and topical terbinafine. The patient was followed-up every month, and the lesion completely cured 2 months later. Herein, we report a case of tinea incognito mimicking photosensitivity in sun exposed area.