A 13-year-old Japanese boy presented with acute skin inflammation on the extremities. He belonged to a judo club of a junior high school in which club tinea capitis and tinea corporis seemed to be prevalent. Vesicles and pustules appeared on his right forearm and right leg. They increased in numbers and formed annular lesions. Pruritic erythema appeared surrounding these lesions. Direct microscopic examination of the lesions detected hyphae, and culture for the fungi yielded yellowish colonies. The result of culture from pustules revealed Staphylococcus aureus. At first, a topical antifungal drug and systemic antibiotics seemed to cure annular lesions, but pustules arose again. A large surrounding erythema was cured by topical treatment with a steroid agent. A biopsy specimen from a pustule showed hyphae of fungi within a hair shaft and in the bulb. The restriction fragment length polymorphism in the internal transcribed spacer regions of the ribosomal gene (polymerase chain reaction restriction fragment length polymorphism) revealed a banding pattern compatible with Trichophyton tonsurans. Treatment with systemic itraconazole was begun and lesions disappeared immediately. Systemic antifungal therapy was needed in our case. Tinea corporis with inflammation necessitates systemic antifungal therapy.