According to WebMD, white spots on the leg may be due to skin issues such as vitiligo, a condition characterized by the development of white patches on the skin. Other potential causes are idiopathic guttate hypomelanosis, also called white age spots, along with tinea versicolor, or skin depigmentation, caused by a fungus.
As noted by Progressive Health, many white spots that develop on the leg are due to aging. These spots often indicate a loss of pigmentation in the affected area, and show up on people of various ages and races. White spots on the skin are particularly prominent in individuals living in hot and humid climates. Treatment for natural causes may include improving physical appearance through light therapy or corticosteroid creams, while anti-fungal medications frequently treat tinea versicolor.