Vitiligo (pronounce /ˈvɪtlˈaɪgoʊ/) or leukoderma is a chronic skin disease that causes loss of pigment, resulting in irregular pale patches of skin. The precise cause of vitiligo is complex and not fully understood. There is some evidence suggesting it is caused by a combination of auto-immune, genetic, and environmental factors. The population incidence worldwide is considered to be between 1% and 2%.