A condition in which the skin is lighter in color than normal. It occurs when special cells in the skin do not make enough of the pigment called melanin. Hypopigmentation can affect a small area of the skin or it can be widespread. It usually appears as lighter than normal colored patches on the skin or as areas on the skin that appear white. Hypopigmentation may be caused by injury, inflammation, or infection of the skin; some medical conditions; or certain medicines.