Vitiligo is apparently caused by inheritance of multiple causal genes simultaneously, possibly in different combinations in different people, plus exposure to environmental risk factors or triggers that are not yet known. Phenols, and stress whether emotional or physical, are suspected to be environmental triggers, but research continues into these and other possibilities.

Vitiligo also tends to occur more often with certain other autoimmune diseases, such as hyper- or hypo-thyroidism (an over- or under-active thyroid gland), adrenocortical insufficiency (underproduction of corticosteroid hormone by the adrenal gland), rheumatoid arthritis, adult-onset type 1 diabetes, psoriasis, systemic lupus erythematosus, and pernicious anemia (subnormal red blood cell level caused by inability to absorb vitamin B12). This suggests that these different autoimmune diseases probably share at least some predisposing genetic or environmental causal factors, although these mostly remain unknown.

Vitiligo affects both genders and all races, but is more noticeable in people with darker skin.

Vitiligo can start at any age but about half of those with vitiligo develop it before the age of 20, and about 95% before age 40.

Approximately 20% of vitiligo patients have a family member with the same condition. However, only 5% to 7% of children will get vitiligo even if a parent has it.

Dr. Richard Spritz spent many years researching the genetics of vitiligo. His work began with families that have more than one member with vitiligo in hopes of isolating a gene. Through this work came his discovery of the NALP1 gene that seems linked to vitiligo and closely related autoimmune diseases. He is currently working on a genome association study that will take all of the genes within the human genome and examine them for the possibility of being associated with vitiligo. He recruited teams of researchers in countries all over the world to join in this effort and collect saliva samples of both vitiligo patients and healthy controls in order to identify suspect genes.