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All that's ringy is not ringworm.

Meaning of the term "ringworm"

The term "ringworm" or "ringworms" refers to fungal infections that are on the surface of the skin. (The early belief was that the infection was due to a worm, which it is not, although the name has stuck.) Some of these fungi produce round spots, but many do not. On the other hand, many round spots are not fungus. 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 gets us back to worms. 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.

Causes of ringworm

Although the world is full of yeasts, molds, and fungi, only a few cause skin problems. These agents are called the dermatophytes, which mean "skin fungi." 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.

Sources of skin fungi

Some fungi live only on human skin, hair, or nails. Others live on animals and only visit humans sometimes. Still others live in the soil. It is often difficult or impossible to identify the source of a particular person's skin fungus.

Heat and moisture help fungi grow and thrive, which makes them more common 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" are neither jocks nor athletes.

Types of ringworm

Among the types of ringworm, or tinea, are the following:

Tinea barbae:

Ringworm of the bearded area of the face and neck, with swellings and marked crusting, often with itching, sometimes causing the hair to break off. In the days when men went to the barber daily for a shave, tinea barbae was called barber's itch.

Tinea capitis:

Ringworm of the scalp commonly affects children, mostly in late childhood or adolescence. This condition may spread in schools. Tinea capitis appears as scalp scaling that is associated with bald spots (in contrast to seborrhea or dandruff, for instance, which do not cause hair loss).

Tinea corporis:

When fungus affects the skin of the body, it often produces the round spots of classic ringworm. Sometimes, these spots have an "active" outer border as they slowly grow and advance. It is important to distinguish this rash from other even more common rashes, such as nummular eczema. This condition, and others, may appear similar to ringworm, but they are not fungal and require different treatment.

Tinea cruris:

Tinea of the groin ("jock itch") tends to have a reddish-brown color and to extend from the folds of the groin down onto one or both thighs. Other conditions that can mimic tinea cruris include yeast infections, psoriasis, and intertrigo, a chafing rash which results from the skin rubbing against the skin.

Tinea faciei:

Ringworm on the face except in the area of the beard. On the face, ringworm is rarely ring-shaped. Characteristically, it causes red, scaly patches with indistinct edges.

Tinea manus:

Ringworm involving the hands, particularly the palms and the spaces between the fingers. It typically causes thickening (hyperkeratosis) of these areas, often on only one hand. Tinea manus is a common companion of tinea pedis (ringworm of the feet). It is also called tinea manuum.

Tinea pedis:

"Athlete's foot" may cause scaling and inflammation in the toe webs, especially the one between the 4th and 5th toes. Another common form of tinea pedis produces a thickening or scaling of the skin on the heels and soles. This is sometimes referred to as the "moccasin distribution." In still other cases, tinea causes blisters between the toes or on the sole.

Diagnosis of ringworm

Sometimes, the diagnosis of ringworm is obvious from its location and appearance. Otherwise, skin scrapings for microscopic examination and a culture of the affected skin can establish the diagnosis of tinea or rule it out.

Treatment of ringworm

Ringworm can be treated topically (with external applications) or systemically (for example, with oral medications):

Topical treatment for ringworm:

When fungus affects the skin of the body or the groin, many antifungal creams can clear the condition in two weeks or so. Examples of such preparations include those that contain clotrimazole (Cruex cream, Desenex cream, Lotromin cream, lotion, and solution, and Lotrisone cream); miconazole (Monistat-Derm cream and Lotrimin cream, powder, and spray); ketoconazole (Nizoral cream and shampoo); and terbinafine (Lamisil cream and solution). These treatments are effective for many cases of foot fungus as well.

Systemic treatment for ringworm:

Some fungus infections do not respond well to external applications. Examples include scalp fungus and fungus of the nails. To penetrate these areas, oral medications are necessary.

For a long time, the only effective antifungal tablet was griseofulvin (Fulvicin, Grifulvin, and Gris-PEG). In recent years, newer agents have been introduced that are both safer and more effective. These include terbinafine (Lamisil), itraconazole (Sporanox), and fluconazole (Diflucan). Reputations die hard, however, and many people continue to fear that even these newer agents are "bad for the liver," when in fact they are quite safe when used properly.

Prevention of ringworm

Conventional wisdom holds that minimizing sweat and moisture can help prevent fungal infections. Common recommendations along these lines are for men to wear boxer shorts, for women to avoid panty hose, and so forth. Whether these measures, some of which are quite difficult to implement, are really worth all of the effort is open to question.

One thing is sure though: white socks (which are often recommended for athlete's foot) are not necessary!


Get the diagnosis of ringworm right!

No practicing dermatologist can get through a week without seeing at least a few patients who are having trouble clearing up "a fungus" that they have diagnosed on their own or had a physician diagnose for them. Nine times out of 10, their frustration follows from the fact that they never had fungus to begin with. When that happens, the diagnosis of ringworm must be reconsidered and a correct diagnosis established.