In vitiligo, the skin cells responsible for producing the pigment, melanocytes, progressively lose their function or are destroyed. Yet, the exact cause of vitiligo is still not well understood. Over the years, many hypotheses have been proposed to explain the sudden loss of melanocytes in the skin. Most experts agree that vitiligo is likely to be the result of a combination of many genetic, immune and triggering factors.
Substantial research is being undertaken to determine its cause and spread. Globally, many researchers are investigating defects in melanocytes (the cells that produce pigment in the skin), and the role of free radicals such as nitric oxide in creating or spreading lesions.
The most widely accepted theory for the progressive loss of melanocytes is the autoimmune theory. The autoimmune theory proposes that, in vitiligo, the immune system reacts against the body’s own cells and tissues, resulting in the destruction of melanocytes. Segmental vitiligo is a less common type of vitiligo, accounting for between five and ten percent of cases. This subtype of vitiligo is less commonly associated with autoimmunity, unlike nonsegmental vitiligo.
Studies have suggested that genetic factors play an important role in the development of vitiligo with around 20% of people with vitiligo, reporting the skin disorder in relatives. Multiple genes are expected to be involved with different combinations inherited by different people. This is perhaps partly responsible for the extreme variability seen in vitiligo fighters. More than 20 genes have been recognized to date which are believed to have some role in the development of vitiligo.
Yet, the chances are that vitiligo is not going to pass on if you have a family member with the condition. However, vitiligo, for being an autoimmune condition, can have some genetic predisposition.
Toxins released by nerve ending
The most common theory for segmental vitiligo is called the neural theory. The neural theory proposes that certain chemicals released from the nerve endings are toxic to the melanocytes and cause their destruction, leading to the absence of melanin production in the skin in segmental vitiligo.
Generally, the skin melanocytes possess a protective mechanism to eliminate toxic melanin precursors and free radicals. But, vitiligo may involve a biochemical imbalance of this mechanism, leading to an accumulation of toxic chemicals and free radicals which can damage melanocytes.
One of the newer theories suggests that the cause of vitiligo is oxidative stress. According to a study by the US National Library of Medicine and National Institutes of Health, oxidative stress (an overaccumulation of hydrogen peroxide, aka H2O2, in the skin) is involved in the pathophysiology of vitiligo. This might hint that oxidative stress triggers the chronic skin disorder in the first place.
Many experts firmly believe that autoimmunity and oxidative stress strictly interact to determine melanocyte loss in an individual. This means adding a greater influx of antioxidants to the diet can slow the progression of the spread and has the potential to reverse the skin condition as well.
The proteins in the body which are involved in the pigment reprocess play a specific role in creating or spreading vitiligo. Their deficiency could also result in the gradual development of vitiligo. In fact, Panchkarma, a treatment line of Ayurveda, treats vitiligo on the nutrition deficiency basis.
Other Possible Vitiligo Triggers
A well-established theory is that vitiligo is initiated by a trigger. Common vitiligo triggers can include the possible involvement of viruses, hormonal changes such as pregnancy, exposure to some industrial chemicals and trauma to the skin. The location of nonsegmental vitiligo is subject to repeated trauma to the skin such as continuous pressure from wearing hats or friction from jewelry and clothing.
People who go through extreme stress or psychological trauma can also show signs of vitiligo. Some hormone disturbances like thyroid hypothyroidism can be a coexisting condition in vitiligo. This might hint at their strong link to the chronic skin disorder.