Causes of tinea (pityriasis) versicolor skin yeast infections are factors like hot climate, humidity, profuse sweating (hyperhidrosis), high levels of skin oil, malnutrition and immunodeficiency.
Malassezia furfur, the yeast responsible for causing tinea versicolor is one of the normal flora of the human skin and is a saprophyte. Apparently healthy persons are also found to get infected and get tinea versicolor. However Malassezia furfur, being an opportunistic, triggered by conducive factors becomes a pathogen causing these yeast infections. Factors conducive in conversion of this yeast into a parasite and pathogen are discussed below.