n :  a chronic noninflammatory infection of the skin esp. of the trunk that is caused by a lipophilic fungus (Pityrosporum orbiculare syn. Melassezia furfur) and is marked by the formation of irregular macular patches that often appear lighter than the surrounding area if the skin is tanned and may appear darker than the surrounding skin if the skin is not tanned or black - called also pityriasis versicolor  .
 
 
 
Published under license with Merriam-Webster, Incorporated.  © 1997-2004.