Although multiple hypotheses have been suggested as possible triggers that cause vitiligo, the 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 believed to play an important role.
The TYR gene encodes the protein tyrosinase, which is not a component of the immune system, but is a melanocyte enzyme that catalyzes melanin biosynthesis, and an important autoantigen in generalized vitiligo. The National Institutes of Health state that some believe that sunburn can cause or exacerbate the condition, but that this idea is not well supported by good evidence.
The researchers believe that autoimmunity plays a role in vitiligo. It is when your immune system incorrectly identifies a part of your body, in this case the cells called melanocytes, that strangers and begin to attack them. People with other autoimmune diseases, especially Hashimoto's disease (which affects the thyroid gland) and alopecia (which causes hair to fall out), are also more likely to get vitiligo.
Variations in genes that are part of the immune system or melanocytes have been associated with vitiligo. It is also believed to be caused by the immune system that attacks and destroys skin melanocytes.
Oxidative stress is an imbalance in certain types of compounds (free radicals and antioxidants) involved in different physiological processes. The imbalance can be caused by exposure to UV rays, pollutants, or other environmental factors. The areas of your body affected by vitiligo are known to be the most vulnerable to oxidative stress.
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, systemic lupus erythematosus and celiac disease.
Among the inflammatory products of NALP1 are caspase 1 and caspase 7, which activate the inflammatory cytokine interleukin-1β. Interleukin-1β and interleukin-18 are expressed at high levels in people with vitiligo. In one of the mutations, the amino acid leucine in the NALP1 protein was replaced by histidine (Leu155 → His). The protein and original sequence are highly conserved in evolution and are found in humans, chimpanzees, rhesus monkeys, and baby bush. Addison's disease (usually an autoimmune destruction of the adrenal glands) can also be seen in people with vitiligo.