What is tinea versicolor?

Tinea versicolor is a fungal infection caused by an overgrowth of the yeast that naturally exists on the skin. It mainly affects the trunk of the body and extremities and, unlike other forms of tinea, is not contagious.

Causes

Tinea versicolor is caused by a type of fungus, called yeast. Yeast are normally present on the skin in low levels. However, when yeast grow out of control they cause skin irritation. It is not clear why the yeast overgrow on some people and not others, but it tends to occur in people with oily skin, compromised immune systems and those living in tropical, humid areas.

Immune systems

The organs and cells involved in protecting the body against infection.

Risk factors

Risk factors for tinea versicolor include:

  • Hot, humid weather;
  • Oily skin;
  • Sweating excessively, and;
  • A weakened immune system.

Signs and symptoms

Tinea versicolor typically appears as spots that are lighter than the unaffected skin, although it may also appear as darker spots. The spots can be white, red, pink, brown or tan and may itch, or appear dry and scaly. These spots may disappear in cooler months and reappear in warmer, humid months. Tinea versicolor may cover a small area of the body or spread over entire sections, such as the torso. It usually appears on the arms, neck, thighs, trunk and genitals.

fungal skin infection of the back, patches of skin on back and trunk, yeast skin infection on back.Visual appearance of tinea versicolor on the back.  

Methods for diagnosis

Although diagnosis is often made based on symptoms alone, the following tests are sometimes done to help your doctor to make a diagnosis:

Wood's light

A yellow-green glow is observed when the affected area is viewed under the ultraviolet light of a Wood's light.

Potassium hydroxide exam

A scraping of your skin from the affected area is added to potassium hydroxide solution and examined under a microscope. Potassium hydroxide destroys only non-fungal cells, making it easier to see if any fungal cells are present in the sample.

Skin biopsy

A skin biopsy is performed only when other skin infections must be ruled out.

Types of treatment

Tinea versicolor is treated with topical antifungal creams, such as ketoconazole, which are applied directly to the affected area. Oral antifungal medications are used for infections that do not respond well to a topical cream.

Potential complications

Tinea can spread easily to other parts of the body. It can cause breaks in the skin, which may result in permanent scarring or lead to bacterial infections. It can also result in discoloration of the skin, which can last for several months after treatment.

Prognosis

Although treatment for tinea versicolor can usually bring it under control, it is common for it to come back. The skin discoloration can also last for several months after infection has subsided.

Prevention

As yeast occurs on the skin normally, tinea versicolor cannot be prevented, but yeast overgrowth can be managed by using antifungal agents.