Ringworm of the skin usually causes a very itchy rash. It often makes a
pattern in the shape of a ring, but not always. Sometimes
it is just a red, itchy rash.
If you have a ring-shaped rash, you very likely have ringworm. Your doctor
will be able to tell for sure. He or she will probably look at a scraping from
the rash under a microscope to check for the ringworm fungus.
Read more about the diagnosis and treatment of ringworm.