What are the aims of this leaflet?
This leaflet has been written to help you understand more about pityriasis versicolor. It tells you what it is, what causes it, what can be done about it, and where you can find out more about it.
What is pityriasis versicolor?
Pityriasis means a type of fine skin scaling, and versicolor means changing colour. It is a common and harmless rash due to the overgrowth of yeasts that live on everyone’s skin. These yeasts, called Malassezia, are not related to yeast in food or to those that cause thrush. It is also sometimes called tinea versicolor.
What causes it?
Large numbers of tiny harmless organisms, known as ‘the resident flora’, live on the surface of everyone’s skin. Some of them are yeasts. At times, these yeasts can overgrow and trigger the rash known as pityriasis versicolor. This happens most often in warm moist climates. Most people with this condition are in good health.
The rash has a mixture of colours– hence the name ‘versicolor.’ It looks pale brown or pinkon untanned, white skin, but sunlight will cause the yeasts to make chemicals that prevent tanning, so the rash stays paler than the surrounding skin. For this reason, the rash is often noticed for the first time after exposure to the sun such as following a sunny holiday.
The condition is most common in people in their early 20s. People who get it may also have dandruff which is caused by a similar yeast overgrowth on the scalp. We do not understand why some people tend to get it and others do not.
Is it hereditary?
What are its symptoms?
The rash can be mildly itchy but usually causes no trouble apart from its appearance. It often goes unnoticed if only a few patches are present.
What does it look like?
The rash usually affects the torso but can also affect the upper arms, neck and stomach. Flat, slightly scaly areas of altered colour appear more obvious against a background of unaffected skin. The colour of the patches may vary from pale to dark brown. On white skin the affected areas usually appear darker than surrounding skin and in dark skinned people the affected patches can appear pale.
How will it be diagnosed?
The diagnosis is usually made by your doctor looking at the rash. A special ultra-violet lamp, known as Wood’s lamp, can be used to look for yellow fluorescence which is typical of pityriasis versicolor. Sometimes your doctor may take skin scrapings to confirm the diagnosis. If there is any doubt, very occasionally a skin (biopsy) [this is when a small sample of skin is cut out to look at under the microscope] may be considered.
Can it be cured?
Yes, the rash clears with treatment although the pale areas will take several months to return to their normal colour. Importantly, this does not mean treatment has failed. The rash often recurs as the yeasts that cause it to live on normal skin and cannot be eradicated completely. Pityriasis versicolor does not leave scars.
How can it be treated?
Treatments applied to the skin:
Most patients are treated with topical antifungal agents that are applied to the skin. Treatments that reduce the amount of skin yeasts include terbinafine cream, clotrimazole cream and miconazole cream. Ketoconazole and selenium sulphide shampoos can be used as body washes but should not be left on the skin.
Medicines taken by mouth:
These include itraconazole and fluconazole, which can be prescribed by your doctor. They are effective but can have side effects so are usually prescribed for widespread rashes, or when topical treatment has failed.
The rash of pityriasis versicolor often comes back. Occasional use of an anti-dandruff shampoo as a bodywash may reduce the chance of this happening.
What can I do?
It may help if you wash with an anti-dandruff shampoo for a few weeks before you go on a sunny holiday to reduce the level of skin yeasts. There is no evidence that the complaint is related to yeast in food so there is no need to change your diet.
Where can I get more information about it?
Web links to detailed leaflets:
For details of source materials used please contact the Clinical Standards Unit (firstname.lastname@example.org).
This leaflet aims to provide accurate information about the subject and is a consensus of the views held by representatives of the British Association of Dermatologists: individual patient circumstances may differ, which might alter both the advice and course of therapy given to you by your doctor.
This leaflet has been assessed for readability by the British Association of Dermatologists’ Patient Information Lay Review Panel
BRITISH ASSOCIATION OF DERMATOLOGISTS
PATIENT INFORMATION LEAFLET
PRODUCED MAY 2008
UPDATED AUGUST 2011, AUGUST 2014, NOVEMBER 2017
REVIEW DATE NOVEMBER 2020