Pityriasis versicolor is caused by the fungus Malassezia furfur. The rash usually starts after adolescence and may be more obvious in pale skin when the surrounding skin is tanned. In darker skin the lesions are hypopigmented. The fungus fluoresces yellow to Wood’s lamp.

What is pityriasis versicolor?

Pityriasis versicolor is a common yeast infection of the skin, in which flaky discoloured patches appear 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 of pityriasisversicolor give rise to the second part of the name, versicolor. Pityriasis versicolor is sometimes called tinea versicolor, although the term tinea should strictly be used for dermatophyte fungus infections.

Who gets pityriasis versicolor?

Pityriasis versicolor most frequently affects young adults and is slightly more common in men than in women. It can also affect children, adolescents and older adults.
Pityriasis versicolor is more common in hot, humid climates than in cool, dry climates. It often affects people that perspire heavily. 
It may clear in the winter months and recur each summer.
Although it is not considered infectious in the conventional sense, pityriasis versicolor sometimes affects more than one member of a family.

What are the clinical features of pityriasis versicolor?

Pityriasis versicolor affects the trunk, neck, and/or arms, and is uncommon on other parts of the body. The patches may be coppery brown, paler than surrounding skin, or pink. Pale patches may be more common in darker skin; this appearance is known as pityriasisversicolor alba. Sometimes the patches start scaly and brown, and then resolve through a non-scaly and white stage.
Pityriasis versicolor is usually asymptomatic, but in some people it is mildly itchy.
In general, pale or dark patches due to pityriasis versicolor do not tend to be more or less prone to sunburn than surrounding skin.
How is pityriasis versicolor diagnosed?
Patients present with patches of hyperpigmentation or hypopigmentation—well-demarcated pale or tan macules with fine scale are usually limited to the upper trunk. Sometimes the whole trunk, the upper arms and the neck (but not the face) are affected. The macules can coalesce. Diagnosis is usually clinical.
Pityriasis versicolor is usually diagnosed clinically. However, the following tests may be useful.
  • Wood lamp (black light) examination— yellow-green fluorescence may be observed in affected areas
  • Microscopy using potassium hydroxide (KOH) to remove skin cells—hyphae and yeast cells that resemble spaghetti and meatballs are observed
  • Fungal culture—this is usually reported to be negative, as it is quite difficult to persuade the yeasts to grow in a laboratory
  • Skin biopsy—fungal elements may be seen within the outer cells of the skin (stratum corneum) on histopathology. Special stains may be required.
 
Treatment from eTG – 
 
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