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Ringworm
(Tinea)

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Medical Author:

Melissa Conrad Stöppler, MD

Melissa Conrad Stöppler, MD

Melissa Conrad Stöppler, MD, is a U.S. board-certified Anatomic Pathologist with subspecialty training in the fields of Experimental and Molecular Pathology. Dr. Stöppler's educational background includes a BA with Highest Distinction from the University of Virginia and an MD from the University of North Carolina. She completed residency training in Anatomic Pathology at Georgetown University followed by subspecialty fellowship training in molecular diagnostics and experimental pathology.

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Medical Editor:

William C. Shiel Jr., MD, FACP, FACR

William C. Shiel Jr., MD, FACP, FACR

Dr. Shiel received a Bachelor of Science degree with honors from the University of Notre Dame. There he was involved in research in radiation biology and received the Huisking Scholarship. After graduating from St. Louis University School of Medicine, he completed his Internal Medicine residency and Rheumatology fellowship at the University of California, Irvine. He is board-certified in Internal Medicine and Rheumatology.

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What does the term ringworm mean?

The term ringworm or ringworms refers to fungal infections that are on the surface of the skin. The name is derived from the early belief that the infection was due to a worm, which it is not. Ringworm is a fungal infection in the skin. Nevertheless, the name ringworm remains. Some of these fungi produce round spots on the skin, but many do not. On the other hand, many round, red spots on the skin are not due to a fungal infection. A physical examination of the affected skin, evaluation of skin scrapings under the microscope, and culture tests can help doctors make the appropriate distinctions. A proper diagnosis is essential to successful treatment.

The medical term for ringworm is tinea. (Tinea is the Latin name for a growing worm.) Doctors add another word to indicate where the fungus is located. Tinea capitis, for instance, refers to scalp ringworm, tinea corporis to fungus of the body, tinea pedis to fungus of the feet, and so on.

Ringworm occurs in people of all ages, but it is particularly common in children. Ringworm is contagious and can be passed from person to person by contact with infected skin areas or by sharing combs and brushes, other personal care items, or clothing. It is also possible become infected with ringworm after coming in contact with locker room or pool surfaces. The infection can also affect dogs and cats, who may transmit the infection to humans. It is common to have several areas of ringworm at once in different body areas.

What causes ringworm?

Although the world is full of yeasts, molds, and fungi, only a few cause skin problems. These agents are called the dermatophytes, which means "skin fungi." An infection with these fungi is sometimes known as dermatophytosis. Skin fungi can only live on the dead layer of keratin protein on top of the skin. They rarely invade deeper into the body and cannot live on mucous membranes, such as those in the mouth or vagina.

Scientific names for the most common of the dermatophyte fungi that cause ringworm include Trichophyton rubrum, Trichophyton tonsurans, Trichophyton interdigitale, and/or Trichophyton mentagrophytes, Microsporum canis, and Epidermophyton floccosum.

What are the sources of skin fungi?

Some fungi live only on human skin, hair, or nails. Others live on animals and only sometimes are found on human skin. Still others live in the soil. It is often difficult or impossible to identify the source of a particular person's skin fungus. The fungi may spread from person to person (anthropophilic), from animal to person (zoophilic), or from the soil to a person (geophilic).

Heat and moisture help fungi grow and thrive, which makes them more commonly found in skin folds such as those in the groin or between the toes. This also accounts for their reputation as being caught from showers, locker rooms, and swimming pools. This reputation is exaggerated, though, since many people with "jock itch" or "athlete's foot" have not contracted the infection from locker rooms or athletic facilities.

What does ringworm look like?