Tinea versicolor (pityriasis versicolor) is a fungal infection of the topmost layer of the skin causing scaly, discolored patches.
The infection, caused by the yeast Malassezia furfur, is quite common, especially in young adults.
Tinea versicolor rarely causes pain or itching, but it prevents areas of the skin from tanning, producing patches that are lighter in color than surrounding skin. People with naturally dark skin may notice lighter patches. People with naturally fair skin may get darker or lighter patches. The patches are often on the chest or back and may scale slightly. Over time, small areas can join to form large patches.
Doctors can diagnose tinea versicolor by its appearance. Doctors may use an ultraviolet light to show the infection more clearly or may examine scrapings from the infected area under a microscope to confirm the diagnosis.
Topical antifungal cream such as ketoconazole may be used, as well as terbinafine solution spray. Prescription selenium sulfide shampoo is effective if applied full-strength to the affected areas (including the scalp) at bedtime, left on overnight, and washed off in the morning. Treatment is usually continued for 3 or 4 nights. Alternatively, the shampoo can be applied for 10 minutes a day for 10 days. Prescription ketoconazole shampoo is also effective. It is applied and washed off in 5 minutes. It is used as a single application or daily for 3 days.
Antifungal drugs taken by mouth, such as itraconazole, ketoconazole, or fluconazole, are sometimes used to treat widespread, resistant infection (see Fungal Infections: Drugs for Serious Fungal Infections). However, because these drugs may cause unwanted side effects, topical drugs are usually preferred.
The skin may not regain its normal pigmentation for many months after the infection is gone. Tinea versicolor commonly comes back after successful treatment because the fungus that causes it normally lives on the skin. Therefore, many doctors recommend use of 2.5% selenium sulfide shampoo or ketoconazole shampoo monthly or every other month to prevent recurrences. Pyrithione zinc soap may also be used regularly to prevent recurrence.
Last full review/revision August 2008 by A. Damian Dhar, MD, JD