Surprisingly, the causes of vitiligo are yet to be precisely established. Complete knowledge of its etiology has proved elusive, despite decades of intense research. A complex and poorly understood chain of reactions is controlled by many genes involved in the immune system response and melanogenesis. It is beyond our current ability to understand how combinations of seemingly hundreds of genes result in a vitiligo patch.
We do know that an obscure triggering event creates stress in the pigment-producing cells of the skin. An over-reactive immune system mistakenly identifies these stressed-out cells as intruders. Specialize cells called T-cells neutralize these ‘enemies,’ driving progressive skin depigmentation. This can happen to anyone, at any age, in any social group.
The current thinking is that vitiligo represents a group of immune-mediated disorders with a similar outcome – the appearance of white patches on the skin. The convergence theory states that intense psychological stress, genetic predisposition, altered cellular environment, toxins exposure and impaired digestion can all contribute to the initiation process of vitiligo.
Autoimmune mechanisms likely underlie generalized vitiligo, while a more localized phenomenon may be responsible for segmental or focal type. Vitiligo may also develop at the site of physical skin trauma – this is known as the 'Koebner phenomenon.'
Nearly half of vitiligo patients say the disease appeared as a tiny blotch and later spread to a wide pattern after severe physical or mental stress. These are called precipitating factors, because they are not the cause of the disease, but induce its appearance. For instance, liver and thyroid diseases could be precipitating factors for vitiligo.
About half of vitiligo cases begin in childhood, often popping up in springtime without warning. Children with vitiligo may have a higher chance of developing other autoimmune diseases, such as alopecia areata, diabetes mellitus, pernicious anemia, Addison's disease and thyroid disorder. Although rare, hypothyroidism is particularly worrisome in this age group because of its potential impact on growth and health status.
Children born to parents who both have the disorder are more likely to develop vitiligo. However, most children will not get vitiligo even if one parent has it. In children with focal and segmental vitiligo, there is often no family history of vitiligo or other autoimmune disorders.
Generalized vitiligo is associated with a tendency to autoimmune illnesses, the most common being thyroid disease. Weak correlations between vitiligo and endocrinopathies, type 1 diabetes, Addison’s disease, lupus, rheumatoid arthritis, and alopecia areata are also observed. In small studies it was found that vitiligo might negatively affect hearing and eyesight.
On the positive side, vitiligo has a protective benefit against melanoma and other deadly skin cancers. And because of the hyper-active immune system, those with vitiligo often say they are less affected by common colds.
The course of vitiligo is usually progressive, with phases of long-term stability or even spontaneous reversal. The average remission period after successful treatment of active vitiligo is four years.