Ask the Expert: Tinea Versicolor

Q. What is tinea versicolor?
A. Many microorganisms normally live on our skin, including a group of yeast species.  The yeast lives in our pores.  Under certain conditions, it can shift its form from a round or oval yeast shape to a string-like, branching shape.  These branching yeasts are named hyphae.  They can migrate under the skin and they produce an acid that can change the amount of pigment (color) in new skin cells.  In its hyphae form, the yeast causes a rash called tinea versicolor, also called pityriasis versicolor.

Tinea versicolor is common year-round in the tropics and subtropics and is seen in the summer months in more temperate climates.  Sun exposure, use of oils on the skin, naturally oily skin and sweating are all suspected to be triggers that can cause the round or oval yeast to convert to its hyphae form, beginning the infection and rash.  The rash can spread between people who have skin contact.

The rash occurs more often in teenagers and young adults and appears on the back, neck, upper chest, shoulders, armpits and upper arms.  Most people who get this rash are in good health.  However, tinea versicolor is more likely to occur if you have a suppressed immune system, for instance, if you are taking a corticosteroid medication such as prednisone for another health problem.  It is also more common in women who are taking birth control pills and in pregnant women.

Q. What are the symptoms?
A. The skin rash is made up of scattered pink, tan, brown or white marks on the skin.  Each person will get only one of the colors.  These marks are usually flat, without texture.  They may be small round spots or areas that start smaller then get larger and combine with other areas.  The skin may flak at the edge of the rash spots.  The rash may be itchy, especially when a person is hot or sweaty.

The skin spots may be more obvious after skin has been exposed to the sun, because these areas do not tan evenly.

Q. How is it diagnosed?
A. Your doctor may shine a black light on the rash.  Yeast types causing this rash may glow yellow-green under the light, which would confirm the diagnosis.  Your health care provider also can examine skin scrapings under the microscope to see if the yeast is present.

Q. How long does it last?
A. It responds well to treatment in most people, but the changes in skin color may remain for several months, especially if you have spent time in the sun.  Wearing a strong sunscreen and taking other precautions against sun exposure can minimize the difference in skin color between normal skin and skin affected by tinea versicolor.

Q. How can it be prevented?
A. Because the rash occurs mostly in hot, humid conditions, keep your skin as dry and cool as possible when you are in this climate.  This rash can be spread through skin-to-skin contact or by coming in contact with contaminated things such as towels, clothing or bedding.

The rash continues to return in 40% to 60% of people.  If you have had more than one episode of tinea versicolor, skin treatment every two weeks with a shampoo that destroys yeast (such as anti-dandruff shampoos that contain selenium sulfide) can usually prevent the rash from recurring.  This may be especially helpful prior to travel to a tropical climate or during months with warm weather.  Another option is to take antifungal medicines by mouth to prevent the rash from returning.

Q. What is the treatment?
A. Topical treatments including anti-dandruff shampoos such as Selsun, Nizoral, Lamisil and antifungal creams and oral medications such as Nizoral, Sporanox, Diflucan are available for treatment.  Topical treatments usually are used one or two times each day.  Treatment can last days or weeks, depending on how the rash responds.  For 6 months after your original treatment, you may be advised to apply topical treatments occasionally or take one or more doses per month of oral antifungal medicine to help prevent the rash from returning.

Health care providers commonly suggest you wash bed linens and pajamas daily during treatment to avoid reinfection.  Some experts recommend boiling or discarding contaminated clothing if the rash is persistent, believing this is a more certain way to eliminate the yeast.

Q. When should I call my health care provider?
A. If you have a skin rash that you think may be tinea versicolor, you should make an appointment with your doctor to have the rash evaluated.

Q. What is the prognosis?
A. There are no serious complications from tinea versicolor.  In most people, the rash goes away with treatment.  However, it takes several months for the skin to return to its normal appearance.  The rash returns after treatment within 6 months in 40% to 60% of people who don’t use antifungal treatments from time to time to suppress the rash.

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