These infections are commonly called 'ringworm', but are not caused by worms. They are superficial infections of the skin, hair or nails caused by a variety of fungi which otherwise live in the soil, on animals, or sometimes only on people.
Infections are spread by direct skin contact (with humans or animals), or indirectly from contaminated articles on floors or in the soil. Shared changing rooms and showers are often a source of tinea, while some infections are spread by sharing of items such as towels. People shed tiny pieces of skin all the time and if these contain a small amount of the fungus, it is able to survive in the environment and cause infection in someone else.
