What is pityriasis versicolor?

Pityriasis versicolor is a common skin complaint in which flaky discoloured patches appear mainly on the chest and back. The term ‘pityriasis’ is used to describe skin conditions in which the scale appears similar to bran. The multiple colours arising in the disorder give rise to the second part of the name, ‘versicolor’. It sometimes called ‘tinea versicolor’, although the term ‘tinea’ should strictly refer to infection with a dermatophyte fungus.

Clinical features

Pityriasis versicolor affects the trunk, neck, and/or arms, and is uncommon on other parts of the body. The patches may be pink, coppery brown or paler than surrounding skin. They may be mildly itchy. Pale patches may be more common in darker skin; this appearance is known as pityriasis versicolor alba and is less likely to itch. Sometimes the patches start scaly and brown, and then resolve through a non-scaly and white stage.
A yellow-green fluorescence may be observed on examination of affected areas with a Wood's light (long wave ultraviolet A).
Pityriasis versicolor is more common in hot, humid climates or in those who sweat heavily, so it may recur each summer. Pityriasis versicolor does not appear to predispose affected areas to sunburn even when it causes pale white marks.