Worms don't cause ringworm. Rather, this superficial skin infection, also
known as tinea, is caused by fungi called dermatophytes. Fungi are microscopic
organisms that can live off the dead tissues of your skin, hair, and nails,
much like a mushroom can grow on the bark of a tree.
Ringworm is characterized by a red ring of small blisters or a red ring of
scaly skin that grows outward as the infection spreads. Though children are
especially susceptible to catching ringworm, it can affect adults as well.
Read more about ringworm.