Vitiligo consists of white patches of skin that are caused by the loss of melanin, the pigment that gives skin its color. Melanin is produced by special cells called melanocytes, which are destroyed in people who have vitiligo. Experts are still working out the details to understand why this disease occurs, but evidence strongly suggests that vitiligo is an autoimmune disorder, in which the body's immune system mistakenly targets and injures these specific cells within your own body.
Vitiligo can cause minor changes or extensive changes in the skin. In some people, it may be hardly noticeable, while in others it is obvious. In dark-skinned people the vitiligo patches are obvious since they contrast with normal skin. Light-skinned people may have fewer cosmetic concerns, but patches without pigment can become obvious in the summer because unaffected skin tans but vitiligo skin does not tan.
Vitiligo occurs in about 1 percent to 2 percent of the population. Approximately 30 percent of people with vitiligo have a family history of the condition. About half of people with vitiligo start showing symptoms before age 20.
People with vitiligo have an increased risk of developing certain diseases, such as hypothyroidism (an underactive thyroid), hyperthyroidism (an overactive thyroid), type 1 diabetes, Addison's disease (a disease that causes a decrease in the function of the adrenal gland) and pernicious anemia (vitamin B12 deficiency). Also, people with these conditions have an increased risk of developing vitiligo. These medical conditions are all problems that involve the immune system attacking cells in the body.