By Martha A. Simpson, D.O., M.B.A.
Associate Professor of Family Medicine
Ohio University College of Osteopathic Medicine

TINEA VERSICOLOR IS A COMMON FUNGAL RASH AFFECTING YOUTH

Question: I had this rash a while back that was called tinea versicolor. I treated it and now it is back. Please tell me more about this rash and how to prevent it. Is it contagious? Is it common? Will the white spots that are left behind when the rash is gone ever go away?

Answer: Tinea versicolor is a common fungal skin disorder that affects up to 8 percent of the population of the United States. Caused by a yeast-type fungus named Pityrosporon orbiculare, it is more common in people between ages 15 and 24. Race and skin color do not seem to be factors in who gets this infection.

The Pityrosporum orbiculare fungus normally lives on the skin and does not cause infections in most people. Except in the cases of people who are known to have conditions that compromise the immune system, we generally don’t understand why some people are more prone to these infections than others.

However, if you have oily, moist and warm skin, it is the perfect environment for the development of small fungal "colonies" on the surface of the skin. These colonies can then begin to grow rapidly, as this happens they leach out an acidic bleach, which produces a rash. The spots, or patches, of this rash are a light reddish brown on very pale skin. Since these areas don’t tan, they look like white spots on darker or tanned skin.

The rash is usually on the upper back and chest, as well as the upper arms and upper thighs. The rash looks like oval, flat patches, that may have a fine scale on them. The patches vary in size. Most people seek medical advice about this condition, in part because the spots can linger for months.

Tinea versicolor is usually easy for an experienced practitioner to recognize, and extensive testing is not generally needed. The treatment is also fairly straightforward, but the rash frequently recurs -- probably because of reinfection rather than treatment failure. Remember that this fungus normally lives on the skin and causes no problems. This natural “fungus reservoir” is felt to be at the root of many cases of reinfection. Reinfection may also occur because these fungi can live for extended periods of time on dry surfaces and in clothing. This may be more of an issue now that many people do all their wash using only cold water, which may not be adequate to kill the fungi.

Initial treatment for tinea versicolor is usually with a topical antifungal agent. Selenium sulfide lotion -- the base compound for many dandruff shampoos -- can be used. This shampoo is spread over the infected skin, left in place for 10 minutes, then rinsed off. This can be done daily for about a week, and is usually quite effective. The light spots usually slowly return to normal color over a period of several months. The rash tends to recur in the summer when it is hot and humid.

There are also topical antifungal medications that are available by prescription. Your physician might prescribe these. Some physicians treat initially with oral antifungal agents. These work well, but there are side effects and risks with these medications that should be weighed and discussed by you and your physician. Recurrence can sometimes be prevented by avoiding overly hot and sweaty environments as well as by using the topical dandruff shampoo weekly.

Family Medicine® is a weekly column. To submit questions, write to Martha A. Simpson, D.O., M.B.A., Ohio University College of Osteopathic Medicine, P.O. Box 110, Athens, Ohio 45701, or via e-mail to readerquestions@familymedicinenews.org. Medical information in this column is provided as an educational service only. It does not replace the judgment of your personal physician, who should be relied on to diagnose and recommend treatment for any medical conditions. Past columns are available online at www.familymedicinenews.org.