Condition Basics

What is ringworm?

Ringworm is an infection caused by a fungus. It causes a rash that can appear on many different parts of the body. It is called ringworm because it sometimes looks like a ring.

What causes it?

Ringworm is caused by a fungus. It's not caused by a worm. The kinds of fungi that cause ringworm live and spread on the top layer of the skin and on the hair. They grow best in warm, moist areas, such as locker rooms and swimming pools, and in skin folds.

Ringworm is contagious. It spreads when you have skin-to-skin contact with a person or animal that has it. It can also spread when you share things like towels, clothing, or sports gear.

What are the symptoms?

Ringworm usually causes an itchy rash. It often makes a pattern in the shape of a ring, but not always. The rash may be peeling, cracking, scaling, and red. It can affect the face, groin, hands, and other parts of the body.

What happens when you have ringworm?

Ringworm of the skin can start as a small patch of itchy, red, or scaling skin. The rash can spread and cover a large area.

Clothing that rubs the skin can irritate the rash. Sweat, heat, or moisture in the air (humidity) can make the itching and infection worse.

As the infection becomes worse, the ring-shaped pattern and red-brown color may become more visible. If not treated, the skin can become irritated and painful. Skin blisters and cracks can become infected with bacteria and require antibiotics.

Ringworm can also spread to other parts of the body, including the feet, nails, scalp, or beard.

After treatment, the rash will go away. But ringworm can return unless you follow steps to prevent it. The tendency to get fungal skin infections or to have them return after treatment seems to run in families.

How is it diagnosed?

Your doctor will ask about your symptoms and examine your skin and the rash. The doctor may diagnose ringworm based on this exam. He or she may look at a scraping from the rash under a microscope to check for the ringworm fungus.

How is ringworm treated?

In most cases, you can treat ringworm of the skin with antifungal creams or ointments. Many are available over-the-counter.

• Wash the rash with soap and water, and dry it well. For large areas of blistered sores, use compresses such as those made with Burow's solution (available over-the-counter) to soothe and dry out the blisters.
• Apply antifungal cream beyond the edge of the rash.
• To avoid spreading it, wash your hands well after treating or touching the rash.
• Follow the directions on the package. Don't stop using the medicine just because your symptoms go away. You most likely will need to keep doing the treatment for 2 to 4 weeks or longer.
• If symptoms do not improve after 2 weeks, call your doctor.

If your rash does not clear after you have tried different topical antifungals, or if the infection is widespread, you may need prescription antifungal pills.

How can you prevent ringworm?

To help prevent ringworm, keep your skin clean and dry, wear slippers or sandals in locker rooms and public bathing areas, and change your socks and underwear at least once a day. And don't share clothing, sports gear, towels, or sheets.