Vitiligo is a common acquired disorder characterized by well marginated milky white spots resulting from the loss of melanocytes. Vitiligo is associated with risks of ocular abnormalities and some autoimmune disorders. In Indian and some other cultures, this innocuous disease has been associated with social stigma since ancient times. Confusion with leprosy is partly responsible for this.
Aetiology & Pathogenesis
Epidemiological studies suggest that vitiligo or a susceptibility to the disease may be inherited and about one fourth to one third of patients have family members affected with the disease. A multifactorial pattern of inheritance is revealed in most studies.
Three possible mechanisms that may the cause destruction of melanocytes, the pigment producing cells of the skin, has been suggested by different workers.
The autoimmune hypothesis originated from the observation that vitiligo is associated with some autoimmune diseases. Both cellular and humoral factors responsible for autoimmune damage to melanocytes have been demonstrated.
The autocytotoxic or self-destruct hypothesis suggests that some toxic molecules produced during the biosynthesis of melanin are responsible for melanocyte damage in susceptible individuals.
The neural hypothesis postulates that neurochemicals liberated from nerve endings are toxic to melanocytes. The varied clinical and laboratory findings, however, indicate that multiple mechanisms may be responsible for the causation of vitiligo in an individual.
Vitiligo affects all races with an average frequency of 1 to 2 per cent of the population. Both sexes are affected equally and the disease may develop at any age. The peak age of onset in most series was between 10 and 30 years. Stressful life events or physical trauma can often precipitate the onset of disease.