Pityriasis versicolor

What is pityriasis versicolor?

Pityriasis versicolor, sometimes called tinea versicolor, is a common condition caused by an overgrowth of yeast, leading to the development of scaly discoloured skin patches, which occasionally can be mildly itchy. It most frequently affects young adults but can arise in children and older adults.

What does pityriasis versicolor look like?

The sites most commonly affected are the chest and upper back, but there is often involvement of the upper arms, neck, and abdomen.

The rash arises as many small, round-oval, slightly scaly patches, often joining together to form large areas of affected skin.

On white skin the affected areas usually appear darker than surrounding skin (fawn-coloured or pink); in skin of colour the affected patches are often paler than the surrounding skin.

What causes pityriasis versicolor?

It is caused by a type of yeast called Malassezia (formerly known as Pityrosporum ovale). This yeast is found on the skin of more than 90% of adults, where it normally lives without causing any problems.

Pityriasis versicolor can develop if this yeast starts to multiply more than usual. Although the environmental factors listed below can cause the yeast to multiply, it is not clear why this happens in some people and not in others.

What else can contribute to pityriasis versicolor?

Pityriasis versicolor is more common in hot, humid climates and in people who are prone to heavy sweating, and may clear in the winter months and recur each summer. It is also more common in people who have a weakened immune system.

There is no evidence that it is related to yeast in food so there is no need to change your diet.

Things you can do to help yourself

• Most cases can be treated with a shampoo called Ketoconazole which can be purchased without a prescription. The shampoo should be made into a lather and applied widely to the skin from the jawline down and left on the skin for 5-15 minutes before rinsing off in the shower. This should be done once a day for 5 days

• Wearing clothing that allows your skin to breathe and sweat less may reduce the chance of pityriasis versicolor recurring. If it does return, some people will repeat treatment as described above and then go on to use the shampoo once a month as prevention

• The colour changes may persist for weeks or months, and do not indicate that the treatment has not worked. Recurrence of the condition can be recognised by the presence of fine scale and the rash spreading
  

Make an appointment at your GP surgery

If the rash does not respond to treatment, then make an appointment to see a health professional who is likely to prescribe a short course of an antifungal tablet.

Helping with other skin conditions

If you, a family member, or friend have an undiagnosed skin condition; or you want to learn more about how to treat skin conditions, please view our short video on how to get the best from this website.