Ringworm in humans is a contagious fungal infection caused by common mold-like parasites that live on the cells in the outer layer of the skin. It is not caused by a worm, despite its name. Certain types of fungi cause ringworm, and they thrive where its warm and humid. Ringworm often spreads by direct skin-to-skin contact with an infected person or animal, but it can also be spread through soil, objects, and surfaces that are infected with the fungus. People who live in warm climates, have close contact with an infected person or animal, or have damp or sweaty skin are at higher risk of getting ringworm. Symptoms of ringworm include an itchy, circular rash with clearer skin in the middle. Mild ringworm often responds to antifungal medications applied to the skin, while more severe infections may require antifungal pills for several weeks. To prevent ringworm, it is recommended to keep the skin clean and dry, wear flip-flops in locker rooms and public showers, change socks and underwear at least once each day, and avoid sharing clothes or towels with someone who has ringworm.