5 Answers to Common Questions about this Condition What is this discolored rash on my chest, back, and arms? Tinea versicolor, otherwise known as pityriasis Versicolor, is a harmless but cosmetically disturbing rash that is most often seen on the trunk, arms, and neck.  It is sometimes itchy, but not always.  It can be a variety … Continue reading Tinea Versicolor