Educational/Dermatology


Informational drafts on Dermatological subjects in a complete and simplified form.
For further info write to: info@dermaclub.org






Educational/Dermatology - Pityriasi Versicolor
PITYRIASIS VERSICOLOR


PITYRIASI VERSICOLOR:
A MYCOSIS OF THE TRUNK THAT IS DIFFICULT 
TO UNDERSTAND AND OVERCOME

What is it?

It is one of the most frequent human mycoses (or fungal infections), and develops on the trunk of adults.

 

What does it look like?

It is characterised by roundish spots that may be single or connected to form patches, appear mainly on the trunk and, depending on the stage of infection, may be skin-coloured, pink, brown or white. Patches of different colours can be seen on the same person, which is why the mycosis is called versicolor (variegated). The patches may sometimes scale like dandruff, which is why it is called pityriasis (dandruff). 

 

What causes it?

Pityriasi versicolor is caused by the growth of fungi called Pityrosporum orbiculare or Pityrosporum ovale, which normally live inside the follicles of sebaceous gland-rich areas of adult skin such as the trunk but, under particular (especially warm and moist) conditions, can grow and colonise the skin surface. 
They form round colonies starting from the mouth of a gland. 

 

Why does the skin change colour?

When the fungi start to grow, the roundish colonies may be pink or skin-coloured. When the colonies become detached as result of scaling, treatment or exposure to sunlight, the skin remains a lighter colour, thus making it easier to identify the mycosis. 

 

What is the paradox of the white patches?

The white patches, which are clearly visible against tanned skin during the summer, attract the attention more and suggest that whoever has them is infected. However, paradoxically, they are a sign that the mycosis is disappearing, which may occur spontaneously or as a result of exposure to the sun. 

 

Why is this mycosis commonly called “sea fungus”?

Pityriasis versicolor mainly develops in the autumn and spring but often goes unrecognised because the colonies have the same colour as the skin. After exposure to the sun, the sterilising effect of the ultraviolet rays kill the colonies, which scale and leave the tell-tale white patches that indicate their passing a . 
The white patches return to becoming tanned over time but the fact that people often become aware of having pityriasis versicolor only during their summer holiday has led to the mycosis being improperly christened “sea fungus”.

 

Is pityriasis versicolor contagious?

 

Unlike other mycoses, pityriasis versicolor is not contagious and it is frequent to see only one member of a married couple affected. The fungus is a saprophyte (i.e. a common inhabitant of human skin), and the growth of colonies is an extraordinary effect that only occurs in some people and/or under particular conditions.

 

How is it treated?

The fungi that cause pityriasis versicolor (Pityrosporum orbiculare or Pityrosporum ovale) are highly sensitive to antifungal drugs, and so the infection is easily treated. It is enough to apply an antifungal cream or lotion to the areas of skin affected for ten consecutive days and the colonies disappear. Besides antifungal drugs, Sulfosalicylic cream is very effective . In fact,both sulfur and salicylic acid are highly active against pityriasis versicolor. Sulfosalicylic cream, unlike creams containing antifugal drugs, has a high affinity for the skin and promotes desquamation hence fungus elimination. In practice, SulfoSalicylic cream has to be applied on the neck, trunk and arms for seven days at nightime.

 

Does treatment cure the disease?

Pityriasis versicolor is caused by a fungus that naturally lives inside skin follicles and so, although antifungal treatment removes the colonies that have grown onto the skin, the fungus will remain in the follicles even in the case of oral treatment. Pityriasis versicolor may therefore recur any number of times 
People who have had had the infection should periodically check their skin for the growth of new colonies.

 

How to avoid recurrences ?

Pityriasis versicolor may have many recurrences after the treatment. In order to avoid recurrences, it is recommended to apply Sulfosalicylic cream every 15 days.

 

What does the skin look like after treatment?

After treatment has detached the colonies, the skin may be left with white patches. These should not be treated any further because they disappear spontaneously or as a result of exposure to the sun. 

 

Is it necessary to sterilise clothing after treatment?

 

It is not necessary to sterilise clothing or sheets and towels because the fungus only lives and develops on human skin. Simple washing is sufficient. 

Can UV lamps be used to remove the white patches?

 

Theoretically yes, but it takes a large number of sessions. Like the sun, the first few sessions tan the skin, but the white patches are more resistant and tend to become more noticeable. 

How do you check for the growth of colonies?

As mentioned above, the colonies are often the same colour as the skin and are therefore difficult to see with the naked eye. However, they can be seen under a blue light (Wood’s lamp) as they emit a yellow or green light, and dermatologists can use this to identify the first phases of colonisation and prescribe early treatment.

 

How can the unsightly white patches be avoided during the summer?

In order to avoid the patchiness caused by Pityriasis versicolor when the skin is exposed to the sun, it is necessary to treat the mycosis in the spring after it has been identified by means of a Wood’s lamp examination.