Tinea versicolor is caused by a fungus, Malessezia, which produces very superficial scaling areas which can appear darker or lighter than the background skin color or any color in between. Involved areas are typically on the torso, neck, and upper arms. The lighter color, which is characteristic, is thought to be due to a fungal compound, azelaic acid. It is seen most commonly in the summer months when you try to tan. Although uncommon, involvement below the waist can occur. Because this infection is not inflammatory, most people do not report any symptoms associated with these lesions, but occasional itching can occur. Even after appropriate treatment, it takes months for your normal coloration to be reestablished, so patience and persistence is required for a successful outcome.
Medically reviewed by Norman Levine, MD; American Board of Dermatology
Bigby, Michael, and Hu, Stephanie W. "Pityriasis Versicolor: A Systemic Review of Interventions." Arch Dermatol 146.10 (2010): 1132-1140.