Tinea versicolor is a fungal skin infection that causes the affected skin to change color and become either darker or lighter than the surrounding skin. Unlike some skin ailments, tinea versicolor is not contagious; however, if it goes untreated, the fungus will continue to spread across the body.
Malassezia furfur is a yeast that lives on the skin of most adults. This is also what causes a tinea versicolor skin infection. It is not well understood what influences this fungus to evolve from a harmless fungus living on adult skin without causing problems to a multiplying fungus that causes discolored and scaly skin in teens and young adults. It has been suggested that people may be born with a genetic predisposition to the fungus, but no one has proven this hypothesis.
One exciting aspect of Malassezia furfur is that it produces a chemical that seems to impede the skin’s regular production of pigment, which causes skin areas to change color. While the discoloration is not permanent, it can take several months after treatment for the skin coloration to even out. However, any reddish-brown patches caused during the tinea versicolor infection will disappear immediately after treating the skin.
Tinea versicolor commonly affects the shoulders, back, and chest. Usually, the face is only touched in children, but it’s rare. Because yeast is known to thrive in moist, dark areas, tinea versicolor can also affect the folds of the skin, such as the folds by the armpits, the groin area, or under the breasts in women. These are not usually the areas where the infection originates, but rather the areas it quickly spreads to.
Tinea versicolor is most common in teens and young adults but can also affect children. Because of the skin discoloration, being in the sun or getting overheated can magnify the infection's presence. The extra heat that usually causes the skin to become rosy will not affect the infected areas, which will remain lighter.
Once the skin has had a tinea versicolor infection, the infection can more easily recur. Warm, humid weather encourages the condition to return. Still, because we know this, catching the recurrence in the early stages is more manageable and avoids severe skin discoloration.