A skin infection caused by a fungus, not a worm. Fungus infections also can affect skin on the scalp (tinea capitis), groin area (tinea cruris, also called jock itch), or feet (tinea pedis, also called athlete's foot). There can be several patches of ringworm on the skin at once. The name comes from the characteristic rash: a red ring surrounding an area of normal appearing skin. The infection can be acquired through contact with infected humans, infected animals, or from contact with objects containing the fungus such as bedding, clothes, or hair brushes.