About one out of a hundred people in the US has vitiligo. What exactly causes vitiligo is unclear, but it appears to be linked to an autoimmune process of destruction of melanocytes, which are cells that produce the brown pigment in the skin. The skin problem is also associated with other autoimmune disorders such as hyperthyroidism, pernicious anemia, and Addison’s disease. A hereditary factor may be involved because some have reported that there is an increased incidence within families.