Ringworm is a fungal skin infection that causes a red, circular, itchy rash. Ringworm is officially known as tinea or dermatophytosis. Ringworm is referred to by other names depending on the part of the body that is affected. For example, fungal infection of the feet is athlete's foot or tinea pedia. In the groin area, it is tinea cruris (jock itch). Depending on the location and extent of ringworm infection, topical and/or oral antifungal medications may be prescribed for treatment.