Vitiligo - is the most common chromatosis, 3-4% of people with skin diseases.
Frequency in the population is 0,14-8,8%. Can occur at any age in both sexes and all races. In 25% of cases for the first time begins at the age of 12, 50% - up to 20 years.
Vitiligo white patches appears on different parts of the skin. The disease is often seen as a cosmetic defect, but the evidence of irregularities of the body as a whole system.
Degree and rate of development of the process of depigmentation usually depend on compensation related chronic diseases of the gastrointestinal tract, liver, neurosis and pathology of endocrine glands. In the latter case, the most frequently observed dysfunction of the thyroid gland and the adrenal cortex.
The appearance of white spots due to the destruction of melanocytes, cells located in the basal layer of the skin, with numerous processes.
Education skin coloring agent melanin - a complex biochemical process. It begins with the hydroxylation of essential amino acid phenylalanine to tyrosine, which is activated by the action of tyrosinase by copper ions is oxidized to dihydroxyphenylalanine and then dioksidenilalaninhinon.
As a result of spontaneous oxidation last turns into melanin. Melanin is the melanocytes, which are unicellular glands. From melanocytes are distributed pigment in keratinocytes, moving it to the outer layers of the epidermis, where it has a protective function
from harmful solar radiation and irradiation.
Vitiligo occurs when the destruction of melanocytes not only in the lesion, but also in the surrounding intact skin.
Currently, there are three main hypotheses to explain the development of vitiligo - neural, and autoimmune augodestruktivnaya.
According to the neural hypothesis, high concentrations of neurochemical substances (acetylcholine,
norepinephrine, epinephrine) around the pigment cells reduces the production of melatonin.
The content of acetylcholine in the skin regulates enzyme cholinesterase. With age, the level around
hair follicles is reduced, which leads to an increase in local concentrations of ACh, causing graying hair. By analogy allows for the loss of skin pigment at lower cholinesterase in the microenvironment of pigment cells.
In the occurrence of vitiligo is important, some authors give the neuro-psychological, psycho-emotional factors, stressful situations. A role in this case have metabolic catecholamines. With nervous excitement norepinephrine and other mediators released from nerve endings involved in the destruction of melanocytes. Catecholamine levels in the urine of patients with vitiligo increased. They have a direct cytotoxic effect on melanocytes due to the presence in their structure of the phenolic ring. These
substances are readily oxidized to form toxic radicals. In the skin and mucosal vasoconstriction occurs, leading to hypoxia of the skin and the accumulation of free radicals.
Augodestruktivnaya hypothesis in the origin of vitiligo basic knowledge ¬ chenie gives phenol and its derivatives, which have a cytotoxic effect on pigment cells. Substances with an aromatic or aliphatic chains can cause depigmentation of the skin. Vitiligo is common among workers employed in the manufacture of rubber and plastic products, household chemicals, with various contacts with phenol
and its derivatives. Supposed hereditary sensitivity to phenols.
According to the autoimmune theory, vitiligo considered an autoimmune disease. The basis for this are due to a number of immune disorders - tireiodit Hashimoto, diabetes, thyrotoxicosis, Down syndrome, disgammaglobulinemiya, autoimmune hemolytic anemia, adrenal insufficiency. Attempts to identify antimelanotsitarnye antibodies and cytotoxic lymphocytes were unsuccessful, have been identified as any immunootvetstvennyh genes. Some authors have noted in patients with vitiligo high activity of natural killer cells, with normal T and B lymphocytes. When duration of the disease over 5 years null cells are involved in the process of destruction of melanocytes, although the effect of killer
not specified.
In the pathogenesis of the disease has a significant role the endocrine system, especially the function of the thyroid gland. In some cases, after surgical skin pigmentation is restored.
Uncertainty of the etiology and pathogenesis of insufficient knowledge, persistent chronic disease, susceptibility to the spread of the process cause difficulties in treating vitiligo.
To date there are no radical chemotherapy reducing skin pigmentation. Traditionally appointed agents copper, B vitamins, benzonal, FHG and others do not give the severity of clinical outcome, and the side effects of medication stops the doctor from any destination
therapy, because can lead to iatrogenic diseases.
