Vitiligo

Vitiligo is a disease that is characterized by the loss of skin color in the form of spots. The scale and rate of color loss are unpredictable and can affect any part of the body. This condition is not life threatening and is not contagious. Treatment of vitiligo is to improve the appearance of affected areas of the skin. The disease can not be completely cured.

Epidemiology

According to various studies, in the world the average prevalence of vitiligo among the population is about 1%.

[1], [2], [3], [4], [5], [6], [7], [8],

Causes of the vitiligo

The causes and pathogenesis of vitiligo is still unknown. Currently, the most recognized theories of the emergence of vitiligo are neurogenic, endocrine and immune theories, as well as the theory of self-destruction of melanocytes.

[9], [10], [11], [12]

Risk factors

At present, it is possible to identify a number of previous factors that contribute to the onset of depigmentation. These include: psychological, local physical trauma, pathology of internal organs, intoxication (acute or chronic), childbirth, the action of ultraviolet (or ionizing) rays, burns, etc.

[13], [14], [15], [16], [17], [18]

Pathogenesis

In addition, a number of internal and external factors have been identified that play an important role in the development of dermatosis: cytokines and inflammatory mediators, antioxidant defense, oxidative stress, etc. External factors, such as ultraviolet radiation, viral infections, chemicals, etc., are also important.

However, one should also remember the independent or synergistic influence of the above factors, i.e., the multifactorial nature of vitiligo. In this regard, some authors adhere to the theory of convergence in vitiligo.

The neurogenic hypothesis is based on the location of depigmented spots along the nerves and nerve plexuses (segmental vitiligo), the onset and spread of vitiligo often begins after nervous experiences, mental trauma. When studying the condition of the nerves of the dermis, patients have a thickening of the basement membrane of Schwann cells.

The question of the involvement of the immune system in the pathogenesis of vitiligo has been debated for a long time. Analysis of changes in immunological parameters in vitiligo patients showed that the immunity system plays a certain role in the emergence and development of the pathological process. The presence of a definite deficit in the T-cell (decrease in the general population of T-lymphocytes and T-helpers) and humoral units (decrease of immunoglobulins of all classes), weakening of the factors of nonspecific resistance (phagocytic response) against the background of constant or increased activity of T suppressors indicate violations in the work of the immune system, on the weakening of immunological surveillance, which, in the final analysis, can be one of the triggers in the emergence and development of the pathological process.

The frequent combination of vitiligo with various autoimmune diseases (pernicious anemia, Addison's disease, diabetes, alopecia areata), the presence of circulating organ-specific antibodies and antibodies against melanocytes, as well as the deposition of the C3 component and IgG in the basal membrane zone of the vitiligo skin, increased soluble interleukin-2 RIL-2) in the blood serum and skin confirm participation of an autoimmune mechanism in the development of this disease.

The frequent combination of vitiligo with diseases of the endocrine glands has suggested the involvement of the latter in the development of vitiligo.

The intensification of the processes of lipid peroxidation (LPO), a decrease in the activity of catalase, thioredoxyl reductase in vitilogenous skin, suggested the involvement of LPO in melanogenesis. The presence of vitiligo in family members and in close relatives of patients testifies to hereditary factors in the development of vitiligo. An analysis of the author's own material and literature data on family cases of vitiligo suggested that people with a family history of a family history are at risk and that, with the influence of certain trigger factors, vitiligo spots may appear.

Scientists have not yet come to a consensus on the type of inheritance in vitiligo.

Of particular interest is the study of the relationship of vitiligo with major histocompatibility genes (HLA-system). In studies, HLA haplotypes such as DR4, Dw7, DR7, B13, Cw6, CD6, CD53 and A19 were most often detected. However, the frequency of occurrence of haplotypes may vary depending on the surveyed population.

[19], [20], [21], [22], [23], [24], [25],

Symptoms of the vitiligo

A vitiligo spot is a depigmentation of white or milky white with clear boundaries, an oval shape, a different size. Spots can be separate or multiple and usually not accompanied by subjective sensations. With the usual course, the surface of the vitiligo focus is smooth, smooth, atrophy, telangiectasia and peeling are not observed. This is a general definition of vitiligo.

The color of the vitiligo spot depends on the type of skin and the preservation of the melanin pigment in the lesion. The depigmental focus is usually surrounded by a normally pigmented zone.

With "trichrome vitiligo" (trichrome vitiligo), there is a light brown zone at the site of transition of the central depigmented zone into the surrounding brown (or dark brown) normally pigmented. This intermediate zone has a different width and is clearly visible under the Wood lamp. The spot with trichromatic vitiligo is often located on the body and is usually found in persons with dark skin.

In some patients, the depigmental spot can be surrounded by a hyperpigment zone. The presence of all these colors (depigment, achromic, normal and hyperpigmental) allowed to call this kind of vitiligo quadrichrome vitiligo (four-color)

With point vitiligo, small point depigmented spots are visible against a background of hyperpigmented or normally pigmented skin.

Inflammatory vitiligo is rare. It has reddening (erythema), usually the edges of the vitiligo spot. It is noted that its presence is a sign of the progression of vitiligo.

Under the influence of various irritants or solar insolation, vitiliginous spots (when they are located on the open areas of the skin - the chest, the back surface of the neck, the back surface of the hands and feet) are infiltrated, thicken, the skin pattern changes, which leads to a lichenification of the lesion, especially its edges. This variant of the disease is called vitiligo with raised borders.

It should be remembered that the centers of depigmentation may appear on the site of long-term inflammatory skin diseases (psoriasis, eczema, lupus erythematosus, lymphoma, neurodermatitis, etc.). Such foci are usually called postinflammatory vitiligo (postinflammatory vitiligo) and distinguish them from the primary vitiligo that has arisen quite easily.

Depigmented spots can be located symmetrically or asymmetrically. Vitiligo is characterized by the appearance of new or increased available depigmented spots in the field of mechanical, chemical or physical factors. This phenomenon is known in dermatology as an isomorphic reaction, or the phenomenon of Kebner. With vitiligo after skin changes, the most commonly observed bleaching is hair, called leucotrichia ("leuco" - from Greek white, colorless, "trichia" - hair). Typically, the hair is discolored in the spots of vitiligo, on the head, eyebrows and eyelashes when the depigmented spots on the head and face are localized. The defeat of nail plates with vitiligo (leukonichia) is not a specific sign and the frequency of its occurrence is the same as in the general population. Vitiliginous spots at the beginning of the disease in most patients have a round or oval shape. As the progression progresses, the number of spots increases or merges, the shape of the lesion lesion changes, taking the form of figures, garlands or a geographic map. The number of spots with vitiligo is from single to multiple.

Stages

The clinical course of vitiligo distinguishes the stages: progressive, stationary and the stage of repigmentation.

The most frequently observed single localized spot, which for a long time may not increase in size, that is, be in a stable state (stationary stage). It is customary to talk about the activity or progression of vitiligo when new or increased old depigmentation centers are manifested within three months before the examination. However, in the natural course of vitiligo, a few months later, next to the primary or other areas of the skin, new depigmental spots appear, ie, slow progression of vitiligo begins. In some patients, a few days or weeks after the onset of the disease, there is an exacerbation of the skin-pathological process, or several depigments appear in succession on different parts of the skin (head, trunk, arm or leg). This is a rapidly progressive stage, the so-called vitiligo fulminans (lightning-fast vitiligo).

All these clinical symptoms (leukotrichia, Kebner phenomenon, family cases, hair and mucous membrane damage, duration of the disease course, etc.) in most cases predetermine the progression of vitiligo or are often found in patients with an active skin-pathological process.

[26], [27], [28]

Forms

There are the following clinical forms of vitiligo:

1. a localized form with the following varieties:
   • focal - in one area there are one or more spots;
   • segmental - one or more spots are located along the nerve or plexus;
   • mucous - only mucous membranes are affected.
2. generalized form with the following varieties:
   • acrofascial - defeat of distal parts of hands, feet and face;
   • vulgar - a lot of randomly scattered spots;
   • mixed - a combination of acrophastic and vulgar or segmental and acrophastic and (or) vulgar forms.
3. universal form - complete or almost complete depigmentation of the entire skin.

In addition, there are two types of vitiligo. In type B (segmental), the depigmented spots are located along the course of nerves or nervous plexuses, as, for example, in shingles, and are associated with dysfunction of the sympathetic nervous system. Type A (non-segmental) includes all forms of vitiligo, in which there is no dysfunction of the sympathetic nervous system. Vitiligo of this type is often associated with autoimmune diseases.

Repigmentation in the vitiligenous focus can be induced by sunlight or therapeutic measures (induced repigmentation) or appear spontaneously, inactivity of any factors (spontaneous repigmentation). However, complete disappearance of foci as a result of spontaneous repigmentation is very rare.

There are the following types of repigmentation:

• peripheral type, in which small pigment spots appear along the edge of the depigmented focus;
• Perifollicular type, in which fine pinholes of the size of a pinhead appear around the hair follicles on a depigmented background, which then increase in a centrifugal manner and, in a favorable process, merge and close the lesion;
• A solid type in which the barely perceptible light-brown solid shadow first appears on the entire surface of the depigmented spot, then the color of the entire spot becomes intense;
• edge type, in which the pigment begins to unevenly creep from the side of the healthy skin into the center of the depigmental spot;
• mixed type, in which one can see a combination of several types of repigmentation described above in one hearth or in a number of located foci. The most common combination of perifollicular marginal types of repigmentation.

[29], [30], [31]

Differential diagnosis

In practice, it is often necessary to differentiate vitiligo from secondary depigmental spots that arise after the resolution of primary elements (papules, plaques, tubercles, pustules, etc.) in diseases such as ^

1. psoriasis,
2. neurodermatitis,
3. lupus erythematosus, etc.

However, depigmented spots can be primary elements in other diseases ( pigmentless nevi, syphilis, albinism, leprosy, etc.) and syndromes (Vogt-Kojanogi-Harada, Alszandrini, etc.).

[32], [33], [34], [35], [36], [37], [38]

Treatment of the vitiligo

There are two fundamentally opposite methods of treating vitiligo, aimed at creating the same type of skin pigmentation. The essence of the first method is the discoloration of small normally pigmented skin areas located on the background of continuous depigmentation. The second method is more common and is aimed at enhancing pigmentation or the use of various cosmetics to mask the defect in skin color. This method of treatment can be carried out both surgically and non-surgically.

In the treatment of vitiligo, many dermatologists use a non-surgical method that includes phototherapy (PUVA therapy, short-wave ultraviolet B-rays therapy), laser therapy (low-intensity helium-neon, Eximer-lazer-308 im), corticosteroids (systemic, local), phenylalanine therapy, kellin, tyrosine, melagenin, local immunomodulators, calcium patriol, pseudocatalase, preparations of plant origin.

In recent years, with the development of microsurgery, the use of micro-transplants of cultured melanocytes from healthy skin into a vitiligo focus has been increasingly used.

A promising direction is the use of a combination of several non-surgical, as well as surgical and non-surgical methods of treating vitiligo.

In PUVA therapy, 8-methoxapsoralen (8-MOS), 5-methoxypsoralen (5-MOS) or trimethylpyorapen (TMP) are often used as a photosensitizer.

In recent years, a report on the high efficiency of phototherapy with a wavelength of 290-320 nm. However, such (Broad-band UVB Phototherapy) UVB therapy was less effective than PUVA therapy, which caused the unpopularity of this method of treatment.

Local FTX is used in cases when the patient has a limited form of vitiligo or lesions occupy less than 20% of the body surface. As a photosensitizer abroad, 1% oxaralene solution is used, and in Uzbekistan (and CIS countries) - ammifurine, psoralen, psoberan in the form of 0.1% solution.

There are many reports of the effectiveness of local corticosteroids, immunomodulators (elidel, protopic), calcipatriol (davopsx) in the therapy of the disease.

Whitening (or depigmentation) of normally pigmented skin with vitiligo is used when the patient has depigmented foci occupying large areas of the body and it is practically impossible to induce their repigmentation. In such cases, for coloring the patient's skin in one tone, small islets (or patches) of normal skin are bleached or depigmented with a 20% ointment monobenzine ether hydroquinone (MBEG). First, use 5% ointment MBEH, and then gradually increase the dose until complete depigmentation. Before and after the use of MBEH, it is not recommended for patients to expose the skin to the action of sunlight.