Lea Ann Kraus, age 14, of Shreveport, La., for her question:
WHAT CAUSES RINGWORM?
Ringworm is any of a number of contagious skin diseases caused by certain parasitic fungi and characterized by the formation of ring shaped eruptive patches on the body.
Ringworm is known technically by the name of tinea. Few persons manage to live a normal lifetime without ever becoming infected by one or more types of the many ringworms.
One of the most common types of ringworm is tinea pedis, which is also called athlete's foot. It is not caused by a worm, but by a fungus that is very similar to that which causes bread to mold. The infected areas are covered by itching, cracked skin and in severe cases by discolored, ring shaped patches covered with scales.
Athletes foot may be spread by walking on the moist, infected floors of baths, swimming pools and gymnasiums. To guard against athlete's foot, one should make sure that floors are thoroughly scrubbed. Also, the feet should be kept clean and dry.
Ringworm is caused by dermatophytes, fungi that draw upon the skin for nourishment. Most fungi grow on dead matter and the dermatophytes feed on the dead cells that are constantly shed from the epidermis, or outer skin.
Other common types of ringworm are tinea capitis (ringworm of the scalp), tinea barbae (ringworm of the hair or beard), tinea corporis (ringworm of the body) or tinea unguium (ringworm of the nails).
The normal skin may harbor a number of fungi that remain dormant until the proper conditions present themselves. As an example, fungi on the soles may become active rapidly when socks are soled and the feet are sweaty and warm.
Griseofulvin is a useful antibiotic that doctors often recommend for treating many types of ringworm. It is taken orally in tablet form and passes through the body to the skin, where it apparently interferes with reproduction of the fungi.
Most ringworm also responds well to topical applications keyed to the specific dermatophyte. These may be applied, on doctors orders, in powder or cream form.
Other preparations often used contain sulfur, salicylic acid and benzoic acid. Potassium permanganate is used in minute quantities in cold water soaps for ringworm of the feet. Keeping the skin clean helps, but too much soap or scrubbing may cause irritation.
The term "athlete's foot" is misleading, as it is a disease that is by no means confined to athletes. It is a malady of people who wear shoes. Athletes may be slightly more susceptible simply because they use communal showers.
In tines unguium, the nails may be deformed in a number of ways. They may have thickened areas, long yellow streaks, whitish patches, peeling or crumbling of the skin or combinations of these symptoms. Tinea unguium is usually associated with a fungal infection elsewhere in the body.