Vitiligo is a chronic disorder that causes depigmentation in patches of skin.It occurs when the melanocytes, the cells responsible for skinpigmentation which are derived from the neuralcrest, die or are unable to function. The precise pathogenesis,or cause, of vitiligo is complex and not yet fully understood. There is some evidence suggesting it is caused by a combination of autoimmune,genetic, andenvironmental factors. It is also common inpeople with thyroid disorders. The population incidence worldwide is considered to be less than 1%.Non-segmental vitiligo has a greater prevalence than the disorder's other form.
Signs and symptoms
The most notable symptom of vitiligo is depigmentation of patches of skin that occurs on the extremities. Although patches are initially small, theyoften enlarge and change shape. When skin lesions occur, they are most prominent on the face, hands and wrists. Depigmentation is particularly noticeable around body orifices, such as the mouth, eyes, nostrils, genitalia and umbilicus. Some lesions have hyperpigmentation around the edges. In regards to psychologicaldamage, vitiligo can have a significant effect on the mentalhealth of a patient. Psychologicalstress may even result in an individual becoming more susceptible tovitiligo. Patients who are stigmatised for their condition may experience depression and similar mood disorders.
In Non-segmental vitiligo (NSV), there is usually some form of symmetry in thelocation of the patches of depigmentation. New patches also appear over time,and can be generalised over large portions of the body, or localised to aparticular area. Vitiligo where little pigmented skin remains is referred to asvitiligo universalis. NSV cancome about at any age, unlike segmental vitiligo which is far more prevalent in teenage years.
Segmental vitiligo (SV) differs in appearance, etiology and prevalence from associated illnesses. Its treatment is also different from that of NSV. It tends to affect areas of skin that are associated with dorsal roots from the spine. It spreads much more rapidly than NSV and, without treatment;patches of depigmented skin remain throughout life.