Also Known As: Tinea versicolor, Sun Fungus
Tinea versicolor (also known as Dermatomycosis furfuracea, Pityriasis versicolor, andTinea flava) is a condition characterized by a rash on the trunk and proximal extremities. Recent research has shown that the majority of Tinea versicolor is caused by the Malassezia globosa fungus, although Malassezia furfur is responsible for a small number of cases. These yeasts are normally found on the human skin and only become troublesome under certain circumstances, such as a warm and humid environment, although the exact conditions that cause initiation of the disease process are poorly understood.
The symptoms of this condition include:
- Occasional fine scaling of the skin producing a very superficial ash-like scale
- Pale, dark tan, or pink in color, with a reddish undertone that can darken when the patient is overheated, such as in a hot shower or during/after exercise. Tanning typically makes the affected areas contrast more starkly with the surrounding skin.
- Sharp border 
- Pityriasis versicolor is more common in hot, humid climates or in those who sweat heavily, so it may recur each summer.
- Sometimes severe "pin-prick" itching in the affected areas; usually when the person's body temperature is elevated by exercise or a hot/warm environment, but the person hasn't started sweating yet. Once sweating begins the "pin-prick" itching subsides.
The yeasts can often be seen under the microscope within the lesions and typically have a so-called "spaghetti and meat ball appearance" as the round yeasts produce filaments.
In people with dark skin tones, pigmentary changes such as hypopigmentation (loss of color) are common, while in those with lighter skin color, hyperpigmentation (increase in skin color) are more common. These discolorations have led to the term "sun fungus".