Vitiligo is the most common cause of acquired depigmentation, characterised by well-defined hypopigmented macules (leukoderma) due to loss of melanocytes. Although it affects people of all ethnicities, it is most cosmetically disfiguring in darker skin types. Approximately one-third of affected people are children.
Hypopigmented macules can be single or multiple in nature, most commonly in exposed areas such as the face and hand and skin folds. It can also occur at sites of injury (the Koebner phenomenon).
Vitiligo can be associated with depigmentation of hair (leukotrichia) and retina, although not iris.
Treatment options include topical therapies such as mid to super high potency steroids and other immune modulators, phototherapy and systemic therapies such oral corticosteroids to stabilise rapidly progressing vitiligo.
References
https://dermnetnz.org/topics/vitiligo/
https://www.uptodate.com/contents/vitiligo-pathogenesis-clinical-features-and-diagnosis
https://www.uptodate.com/contents/vitiligo-management-and-prognosis