Vitiligo, an acquired pigmentary disorder of unknown origin, is the most frequent cause of depigmentation worldwide, with an estimated prevalence of 1%. The disorder can be psychologically devastating and stigmatising, especially in dark skinned individuals. Vitiligo is clinically characterised by the development of white macules due to the loss of functioning melanocytes in the skin or hair, or both."
Source : British Journal of Dermatology

The cause is unknown, but the current view is that it is probably linked to autoimmune unbalances in people with with genetic susceptibility. Environmental factors might also play a role.

It's estimated to affect around 1% of people worldwide.

Various theories have been suggested for the cause of melanocyte loss in vitiligo; some have proposed that vitiligo is a multifactorial disease, with both genetic and environmental factors implicated in its initiation. The same causal mechanisms might not apply to all cases, and different pathogenetic mechanisms might work together (convergence or integrated theory), ultimately leading to the same clinical result. The autoimmune or autoinflammatory theory is the leading hypothesis for causation and is supported by strong evidence."

Source : The Lancet 2015

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