Vitiligo is a chronic skin condition characterized by portions of the skin losing their pigment. It occurs when skin pigment cells die or are unable to function. Aside from cases of contact with certain chemicals, the cause of vitiligo is unknown. Research suggests vitiligo may arise from autoimmune, genetic, oxidative stress, neural, or viral causes. Vitiligo is typically classified into two main categories: segmental and non-segmental vitiligo.