Ringworm (also called serpigo) is an infection of the skin, characterized by a reddish to brownish raised or bumpy patch of skin that may be lighter in the center, giving the appearance of a “ring.” Contrary to its name, ringworm is not caused by a worm but by parasitic fungi (Dermatophytosis). It can exist anywhere on the body. Depending on its location, it can also be known as tinea pedis or "athlete's foot" when on the feet, tinea cruris or "jock itch" when on the groin area, tinea corporis when on the body, where it is most commonly referred to as ringworm, or tinea capitis when on the scalp.
Fungi are organisms that survive by eating plant or animal material, those that cause parasitic infection (dermatophytes) feed on keratin, the material found in the outer layer of skin, hair, and nails. These fungi thrive best on skin that is moist, hot, and hidden from the light. Together with the other dermatophytosis, up to twenty percent of the population has one of these infections at any given moment.