Ringworm is a skin infection caused by a fungus, not a worm. Ringworm can occur anywhere on the body; the ringworm of the groin area (tinea cruris) is jock itch while ringworm on the feet (tinea pedis) is athlete’s foot. It is very contagious and can be passed to another person through contact with infected clothing, combs, and surfaces in pools, showers, or bath floors.