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. Half of those affected show the disorder before age 20, though most develop it before age 40.
The global incidence of vitiligo is less than 1%, With some populations averaging 2–3% and rarely as high as 16%Autoimmune diseases such as Addison’s disease, Hashimoto’s thyroiditis, and type 1 diabetes mellitus tends to occur more often in people who have vitiligo. There is no known cure for vitiligo but many treatment options are available including topical steroids, calcineurin
Although multiple hypotheses have been suggested as potential triggers that cause vitiligo, studies strongly imply that changes in the immune system are responsible for the condition. Vitiligo has been proposed to be a multifactorial disease with genetic susceptibility and environmental factors, both thought to play a role.
The TYR gene encodes the protein, tyrosine, which is not a component of the immune system, but is an enzyme of the melanocyte that catalyzes melanin biosynthesis, and a major autoantigen in generalized vitiligo. Some state the sunburns can cause the disease, but there is not good evidence to support this.
Vitiligo is sometimes associated with autoimmune and inflammatory diseases such as Hashimoto’s thyroiditis, scleroderma, rheumatoid arthritis, type 1 diabetes mellitus, psoriasis, Addison’s disease, pernicious anemia, alopecia areata, and systemic lupus erythematosus.
Among the inflammatory products of NALP1 are caspase 1 and caspase 7, which activate the inflammatory cytokine interleukin. Interleukin-1β is expressed at high levels in patients with vitiligo. With one of the mutations, the amino acid lysine in the NALP1 protein was replaced by histidine (Leu155->His). The original protein and sequence is highly conserved in evolution, and is found in humans, chimpanzee, rhesus monkey, and the bush baby. Addison’s disease (typically an autoimmune destruction of the adrenal glands) may also be seen in individuals with vitiligo