Tinea versicolor is a common skin condition caused by an overgrowth of yeast on the skin’s surface. The yeast normally live in the pores of the skin and thrive in oily areas such as the neck, upper chest, and back. An overgrowth results in a fungal infection that causes uneven skin color, scaling, and sometimes itch. Although the light- or dark-colored spots can resemble other skin conditions, a dermatologist can recognize tinea versicolor easily. In most cases, a visual exam of the skin is all that is needed to make the diagnosis. To confirm the diagnosis, scale may be gently scraped from the skin so that it can be examined under a microscope for the presence of yeast. A special light called Wood’s lamp also may be used.