We consider vitiligo as both depigmentation and repigmentation disorder. Vitiligo is a multifactorial, life-altering and lifestyle-related skin condition. Where, along with a genetic susceptibility to have weaker melanocytes which are susceptible to specific triggers. Such triggers could vary from patient to patient, one type of vitiligo to another and even these are specific to sites. All the researches and expertise in vitiligo shows that we can only possibly know the contributory factors rather than a single clear causative factor. Vitiligo is like a teamwork of several factors like the weaker cell, free radicals (toxins), lifestyle, diet, stress etc. Ultimately vitiligo is the result of a or few cause/s and few effects thereafter. So, to fight vitiligo we need to intervene at multiple levels with multiple options in variable combinations. These should effectively address both causes and effect to get satisfactory results.
Generalized Vitiligo/ Non-Segmental Vitiligo
It is considered as Free Radical Disease, could be a Lifestyle disorder in the course of the disease progression. Free radicals are the toxins produced in the body during metabolism. Autoimmunity in this type of vitiligo is not necessarily acted in the initial part of the disease mechanism.
The person might have some genetic defect in their melanocytes (colour producing cells) or they might be having increased production of free radicals or decreased neutralization of the same. Autoimmunity means the destruction of our own cells by our immune system. Moreover, most of the patients have Vitamin D deficiency, Vit D usually prevents autoimmunity. Any genetic susceptibility is needed not be hereditary. So, in vitiligo, there might be some genetic defects at above-mentioned levels but one need multiple external and internal factors to induce vitiligo.
Unilateral Vitiligo/ Segmental Vitiligo
In this some cutaneous nerve dies due to unknown reasons, this nerve releases some chemicals which will damage the sensitive melanocytes. Hyperactive autoimmunity will scavenge those damaged cells.
Focal Vitiligo
This is considered as an abortive type of either generalised or segmental vitiligo. Mostly all vitiligo present as focal vitiligo initially and eventually evolves in to either generalised or segmental vitiligo. However, in some cases it might remain as focal vitiligo.
Mixed Vitiligo
In this, over the time segmental vitiligo becomes non-segmental vitiligo. In this combination of both the processes explained above present.
Modified Vitiligo
When patches show significant color and texture mismatch due to previous treatment, such vitiligo is considered as treatment modified vitiligo. Mostly its due to continuous use of psoralens and sun exposure. The tissue grafting techniques like punch grafting and and skin grafting can also lead to color and texture mismatch. Outcome in such patches are less optimal. However, color and texture mismatch can be minimized significantly.
Possible disease mechanism in Vitiligo
Weaker Melanocytes cannot tolerate or neutralize the free radicals or toxins unlike normal cells and with this background, there is an increased production of free radicals/toxins or decreased neutralization or both. Once cells are damaged melanin (antigen) in them stimulate the immune system to produce immune cells which can kill the abnormal and damaged melanocytes. Over the time these cells can even kill normal melanocytes as well. Most of the patients do have Vit D deficiency. Vit D believed to prevent such hyperactivity of immune system against own cells (autoimmunity).
