Tinea versicolor

Definition:

A chronic fungal infection of the skin.

Causes, incidence, and risk factors:

Tinea versicolor is a relatively common skin infection caused by the fungus (yeast) Pityrosporum orbiculare. P. orbiculare is considered part of the normal flora on human skin (the microorganisms that are normally found on the skin of humans) and only becomes infectious under certain circumstances. The most commonly affected sites are the underarm, upper arms, chest, and neck. The typical lesion is a flat discoloration with a sharp border and fine scales. The lesions are typically dark tan with a reddish cast. In blacks, pigmentary changes are common with hypopigmentation (loss of color) or hyperpigmentation (increase in skin color). Itching may or may not be present. Tinea versicolor is more common in hot climates and is associated with increased sweating. It occurs more commonly in adolescents and young men.