“Some diseases do not take life, but they just ruin it.”
—Stephen Rothman
DEFINITION OF VITILIGO
Vitiligo is a common pigmentary disorder of great sociomedical importance. It is defined as a circumscribed, acquired idiopathic, progressive, hypomelanosis of skin and hair, often familiar and characterized by total absence of melanocytes microscopically. This definition includes post-inflammatory, chemical-induced depigmentation, those associated with melanoma, secondary to various dermatoses and after-burns.
Vitiligo is a commonly acquired heritable melanocytopenic disorder characterized by progressive well-circumscribed, cutaneous, white macules, ocular abnormalities, autoantibodies, and a high incidence of, associated disorders, particularly thyroi-ditis, diabetes mellitus and premature leukotrichia. Of discussion, and is mainly based on clinical evidence. The cause of non-segmental vitiligo is still unknown. It seems to require following three factors: (1) a complex of vitiligo susceptibility genes that influence the autoimmune response; (2) genetically abnormal melanocytes; (3) an environmental or physiological factor(s) that activates the genetic program for melanocyte destruction. The current dogma is that there are several genes affecting the immune system and the pigment system that predisposes someone to develop vitiligo. However, a precipitating factor must elicit an interaction between the immune system and the melanocyte, resulting in the destruction of the melanocyte population in discrete areas of the skin. Regarding the segmental type, different pathogenic mechanisms have been proposed, mainly linked to mosaicism phenomenon.
Vitiligo is an acquired depigmenting disorder usually classified as non-segmental and segmental types with a higher incidence of segmental types. The definition of two forms is still a matter.
ORIGIN OF THE WORD VITILIGO
Vitiligo probably derived from Latin word Vitium (blemish) and the suffix-ego. Biblical references to leukoderma as leprosy date from the translations of the Hebrew word ‘Zora'at’ (Leviticus) as lepra.2
Just as the term lepra or leprosy was used casually to refer to a large cluster of cutaneous afflictions, the use of vitiligo has been used by some to refer to the leukodermas associated with melanoma, various dermatoses, senile graying of hair and chemically induced depigmentation.
Vitiligo refers to an idiopathic, acquired sometime familial, leukodermas characterized histologically by the absence of identifiable melanocytes and often by association with other abnormalities. The terms hypomelanosis, amelanosis and depigmentation are not synonymous.
Vitiligo was defined as a pigmentary dystrophy. Moreover, Louis Brocq (1856–1928) noted the lack of pigmentation (achromy) in vitiliginous lesions combined with an increase of pigmentation (hyperchromy) in the lesion's periphery which he called ‘dyschromy’ (Brocq 1892). Moritz Kaposi (1837–1902) was one of the first to describe the histopathalogical features of vitiligo.
- Hypomelanosis—decrease in normal melanin pigmentation.
- Amelanosis—total lack of melanin.
- Depigmentation—loss of previously existing melanin.
- Leukoderma is a generic name of skin relativity or absolutely lightened in color.
- Poliopsis refers to a localized whitening of hair, whereas Lavities refers to a more generalized defect.