Hello...... Tinea Versicolor is a condition that occurs when a natural yeast found on the skin ,grows out of control and begins to change the pigmentation of the skin. When this occurs, patches of skin may become lighter or darker. Tinea versicolor can be caused by a variety of factors including hot weather, oily skin, a weakened immune system, hormonal changes and excessive sweating. This condition is more common in adolescents and young adults, consult dermatologist once..