Ringworm is a fungus infection of the skin; it is not caused by a worm. Ringworm of the skin causes a round rash that may itch and crack.
Ringworm grows well in warm, moist areas, such as locker rooms and swimming pools, and in skin folds. A person can get ringworm by touching someone who has it or by sharing towels, clothing, and sports equipment.
The infection is treated with cream that kills the fungus. If the rash is widespread, a person may need to take pills to kill the fungus.
WebMD Medical Reference from Healthwise