Pityriasis versicolor is a fungal infection of the skin and is caused by a type of yeast that naturally lives on your skin. It's also sometimes called tinea versicolor. When the yeast grows out of control, the skin disease, which appears as a rash, is the result.
This picture shows pityriasis versicolor on the chest of a child.
The infection can happen for any of the following reasons:
- You live in a hot climate
- You sweat a lot
- You have a weakened immune system
Because the yeast grows naturally on your skin, pityriasis versicolor is not contagious. The condition can affect people of any skin colour. It's more likely to affect teenagers and young adults.
Signs and symptoms of pityriasis versicolor
Acidic bleach from the growing yeast causes areas of skin to be a different colour than the skin around them. These can be individual spots or patches. Specific signs and symptoms of the infection include:
- Patches that may be white, pink, red, or brown and can be lighter or darker than the skin around them.
- Spots that do not tan the way the rest of your skin does.
- Spots that may occur anywhere on your body but are most commonly seen on your neck, chest, back, and arms.
The spots may disappear during cool weather and get worse during warm and humid weather. They may be dry and scaly and may itch or hurt, although this is not common.
How pityriasis versicolor is diagnosed
Your doctor can diagnose pityriasis versicolor by what the rash looks like. Occasionally, the doctor may use ultraviolet light, which will make the affected areas appear a fluorescent yellow-green if they're the result of pityriasis versicolor.
Your doctor may also take a skin sample by scraping some skin and scales from the affected area to look at under a microscope. With children, the doctor may lift off skin cells by first firmly attaching clear tape to the affected area and then removing it. The sample then can be stuck directly onto a slide to be looked at with a microscope.
How pityriasis versicolor is treated
Treatment of pityriasis versicolor can consist of creams, lotions, or shampoos that are put on the skin. It can also include medication given as pills. The type of treatment will depend on the size, location, and thickness of the infected area.
Treatment options include:
- Topical antifungal treatments. These products are applied directly to your skin and may be in the form of lotions, shampoos, or creams. They keep the growth of the yeast under control. Over-the-counter anti-fungal topical products containing ingredients such as selenium sulphide, miconazole, or clotrimazole are available. But sometimes prescription medications may be needed.
- Oral antifungal treatments. These may be used to treat more extensive or recurrent cases of pityriasis versicolor. Or in some cases they may be used because they can provide a simpler and quicker resolution of the infection.
Treatment usually eliminates the fungal infection. However, the discolouration of the skin may take up to several months to resolve.