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Understanding Ringworm -- the Basics

What Is Ringworm?

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.

What Causes Ringworm?

Ringworm is caused by a fungus that grows on the skin. Once the fungus is established, it spreads out in rings. The center of the ring may clear up, while a new ring of infection develops at the edge of the old ring.

Children are most likely to get ringworm. Ringworm of the scalp can spread from child to child when children share hats, combs, or brushes. Ringworm of the body can be spread on towels, clothing, or sports equipment. Personal hygiene is important in preventing the spread of ringworm. Dogs and cats can be infected with ringworm, too, and they can pass it to people through direct contact.


WebMD Medical Reference Reviewed by Melinda Ratini, DO, MS on April 14, 2015



American Academy of Family Physicians: "Tinea Infections."

Merk Manuals: "Ringworm (Tinea)."

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