Red flat lichen

Red flat lichen is a common non-contagious inflammatory disease of the skin and mucous membranes, the course of which can be both acute and chronic.

The cause of the development of this disease is still not known.

[1]

Epidemiology

The general prevalence of red flat lichen in the general population is about 0.1 - 4%. It occurs more often in women than in men, in a ratio of 3: 2, and in most cases is diagnosed at the age of 30 to 60 years.

[2]

Causes of the red flat lichen

The causes and pathogenesis of red lichen are not established. Red lichen planus is a polythiolotic disease that most often develops due to taking medications, contact with chemical allergens, primarily with reagents for color photography, infections, especially viral, neurogenic disorders. The defeat of the mucous membrane of the oral cavity with red flat lichen is often due to hypersensitivity to the components of dental prostheses and seals. There are data on the relationship of the disease with liver disease, disorders of carbohydrate metabolism, autoimmune diseases, primarily with lupus erythematosus.

There are theories of viral, infectious-allergic, toxic-allergic and neurogenic origin of the disease. In recent years, studies have shown that in the pathogenesis of red lichen planus, changes in the immunity system are of great importance. This is evidenced by a decrease in the total number of T-lymphocytes and their functional activity, deposition of IgG and IgM in the dermoepidermal border, etc.

[3], [4]

Pathogenesis

With a typical form of red flat lichen, characteristic features are hyperkeratosis with uneven granulosis, acanthosis, vacuolar degeneration of the basal layer of the epidermis, diffuse band-shaped infiltrate in the upper dermis closely adjacent to the epidermis, the lower boundary of which is "blurred" by infiltrate cells. Exocytosis is noted. In the deeper parts of the dermis, there are enlarged vessels and perivascular infiltrates, consisting mainly of lymphocytes, among which are histiocytes, tissue basophils and melanophages. In old foci, infiltrates are less dense and consist predominantly of histiocytes.

Verrux, or hypertrophic, form of red flat lichen is characterized by hyperkeratosis with massive horny plugs, hypergranulosis, significant acanthosis, papillomatosis. As with the typical form, in the upper part of the dermis - a diffuse band-shaped infiltrate from the lymphoid cells, which, penetrating the epidermis, seem to "blur" the lower boundary of the epidermis.

The follicular shape of the red flat lichen is characterized by a sharp expansion of the mouths of the hair follicles, which are filled with massive horny plugs. Hair, as a rule, absent. The granular layer is thickened, at the lower pole of the follicle there is a dense lymphocytic infiltrate. His cells penetrate the epithelial vagina of the hair, as if erasing the boundary between him and the dermis.

Atrophic form of red flat lichen is characterized by atrophy of the epidermis with smoothing of epithelial outgrowths. Hypergranulosis and hyperkeratosis are less pronounced than in the usual form. A streaky infiltration in the dermis is rare, the bowl is perivascular or merging, it consists mainly of lymphocytes, in the sub-epidermal areas proliferation of histiocytes is noted. Always, although with difficulty, you can find areas of "blurring" cells infiltrate the lower boundary of the basal layer. Sometimes among the cells of the infiltrate, a significant amount of melanophages with a pigment in the cytoplasm is detected - the pigment form.

The pemphigoid form of red flat lichen is characterized mainly by atrophic phenomena in the epidermis, by smoothing out its outgrowths, although hyperkeratosis and granulosis are almost always expressed. In the dermis - meager, more frequent perivascalar infiltration of lymphocytes with an admixture of a large number of histiocytes. In some areas, the epidermis exfoliates from the underlying dermis with the formation of cracks or rather large bubbles.

The corolloid form of the red flat lichen is characterized by an increase in the number of vessels around which a lymphocytic infiltrate is detected. Hyperkeratosis and granulosis are much less pronounced, sometimes parakeratosis. It is always possible to see also the individual parts of the epidermal outgrowth the "blurring" of the lower boundary of the basal layer to the vacuolation of its cells.

The histological picture of the lesion with red flat mucus membrane deprivation is similar to that described above, but there is no hypergranulosis and hyperkeratosis, more frequent parakeratosis.

Histogenesis of red lichen planus

In the development of the disease, cytotoxic immune responses in the basal layer of the epidermis are of great importance, since activated cytotoxic T lymphocytes predominate in cell infiltrates, especially long-lasting elements. The number of Langerhans cells in the epidermis is significantly increased. RG Olsen et al. (1984) with the help of an indirect immunofluorescence reaction were detected and spiny and granular layers of epidermis specific for red flat anticholinergic antigen. In an immunoelectron microscopic study of the pemphigiform form, C. Prost et al. (19? 5) found deposits of the IgG and C3 complement components in the lamina hicula of the basal membrane in the peribullic zone of the lesion as in the bullous pemphigoid, but unlike the latter they are not in the bladder cover but in the region of the basal membrane along the bottom of the bladder. Family cases of the disease indicate a possible role of genetic factors, in favor of which is also indicated by the possibility of association of red flat lichen with some antigens of tissue compatibility of the HLA system.

[5], [6]

Histopathology of lichen planus

Histologically, hyperkeratosis, a thickening of the granular layer with an increase in keratogialin cells, uneven acanthosis are characteristic. Vacuolar degeneration of cells of the basal layer, diffuse band-shaped infiltration of the papillary dermis layer, consisting of lymphocytes, much less often - histiocytes, plasma cells and polymorphonuclear leukocytes and closely adjacent to the epidermis with infiltration of the cells into the epidermis (exocytosis).

Symptoms of the red flat lichen

The disease is often found in adults, mainly in women. A typical form of red flat lichen is characterized by a monomorphic rash (1 to 3 mm in diameter) in the form of polygonal papules of red-violet color with an umbilical impression in the center of the element. On the surface of larger elements, the Wickham grid is visible (opaline white or grayish points and strips are a manifestation of uneven granulosis), which is well manifested when the elements are lubricated with vegetable oil. Papules can merge into plaques, rings, garlands, and be arranged linearly. In the stage of exacerbation of dermatosis, a positive Köbner phenomenon is observed (the appearance of new rashes in the area of skin trauma). Eruptions are usually localized on the flexural surfaces of the forearms, wrist joints, waist, abdomen, but may appear on other areas of the skin. The process can sometimes take a widespread nature, up to universal erythroderma. Regression of the rash is usually accompanied by hyperpigmentation. The defeat of the mucous membranes can be isolated (oral cavity, genital organs) or be combined with skin pathology. Papular elements have whitish color, mesh or linear character and do not rise above the level of the surrounding mucous membrane. There are also verrocus, erosive-ulcerative forms of lesions of the mucous membrane.

Nail plates are affected in the form of longitudinal grooves, depressions, areas of turbidity, longitudinal cleavage and onycholysis. Subjectively, there is intense, sometimes painful itching.

Forms

There are several clinical forms of the disease:

• Bullous, characterized by the formation of blisters with serous-hemorrhagic contents on the surface of papules or against the background of typical manifestations of red flat lichen on skin and mucous membranes;
• ring-shaped, at which grouping of papules in the form of rings occurs, often with a central zone of atrophy;
• verrucous, in which the rashes are usually located on the lower limbs and are represented by dense warty plaques having a bluish-red or brown color. Such lesions are very resistant to therapy;
• erosive-ulcerative, occurs more often on the mucous membrane of the mouth (cheeks, gums) and genitals, with the formation of painful erosions and ulcers of irregular shape with a red velvet bottom. In other areas of the skin, typical papular elements are noted. It is observed more often in patients with diabetes mellitus and hypertension;
• Atrophic, manifested by atrophic changes along with typical foci of red flat lichen. Possible secondary skin atrophy after resolution of elements, especially plaques;
• pigmentosa, manifested by pigment spots that precede the formation of papules, the face and upper limbs are more often affected;
• Linear, characterized by a linear lesion of rashes;
• psoriatsformnaya, manifested in the form of papules and plaques, covered with scales, having a silvery white color as in psoriasis.

The usual form of red flat lichen is characterized by rashes of small glittering papules of polygonal outlines, red-violet with central navel-like dominion, located mainly on the flexor surface of the limbs, trunk, on the mucous membrane of the oral cavity, genital organs, often grouped in the form of rings, garlands, linear and zosteriform forms. In the mucosa of the oral cavity, along with typical eruptions, there are exudative-hyperemic, erosive-ulcerative and bullous. Peeling on the surface of the papules is usually minor, scales are difficult to separate, sometimes psoriaticiform peeling is observed. After lubricating the knots with vegetable oil, a networked pattern (Wickham mesh) can be found on their surface. Often there are changes in the nails in the form of longitudinal striation and cracks in the nail plates. In the active phase of the process, a positive symptom of Kebner is observed and, as a rule, there is a different intensity of itching.

The course of the disease is chronic, only in rare cases there is an acute onset, sometimes in the form of a polymorphous rash that merges into large foci up to erythroderma. With the long-term existence of the process, especially when localized on the mucous membranes, verrux and erosive-ulcerative forms, the development of cancer is possible. The combinations of red flat lichen and discoid lupus erythematosus with localization of foci mainly on distal sections of extremities with histological and immunomorphological signs of both diseases are described.

Verrux, or hypertrophic, form of red flat lichen is much less common, it is clinically characterized by the presence of shins on the anterolateral surfaces, less often on the hands and other areas of the skin, sharply delineated plaques with a warty surface marked with hyperkeratosis, significantly elevated above the skin surface, accompanied by intense itching. Around these lesions, as well as on the mucous membrane of the oral cavity, typical of a red flat rash of rash may be revealed.

The vegetative form differs from the previous one by the presence of lesions of papillomatous growths on the surface.

The follicular, or pointed, form is characterized by the eruption of pointed follicular nodules with a horny stopper on the surface, at the site of which atrophy and alopecia can develop, especially when there are localized eruptions on the head (Graham-Little-Piccardi-Lassuere syndrome).

Atrophic form is characterized by the presence of atrophy at the site of regressing, predominantly ring-shaped rashes. On the edge of the atrophic elements, one can notice a brownish-cyanotic rim of the remaining infiltration of the rings.

The pemphigoid form of red flat lichen is most rarely seen, it is clinically characterized by the development of vesicle-bullous elements with transparent contents, usually accompanied by itching. Bullous foci are located in the area of papular eruptions and plaque lesions, as well as against erythema or clinically healthy skin. This form can be paraneoplasia.

The corolloid form is very rare, it is clinically characterized by eruptions mainly on the neck, in the shoulder girdle, on the chest, in the abdomen of large flattened papules located in the form of rosaries, reticularly, in the form of strips. Around such foci, typical rashes, often hyperpigmented, can be observed. A.N. Mehregan et al. (1984) do not consider this form a kind of red flat lichen. They believe that this is probably an abnormal reaction of the skin to trauma, which is manifested by the formation of linear hypertrophic scars.

As a variant of red flat lichen, similar in clinical features to the coral form, is considered " keratosis lichenoides chronica ", described by M.N. Margolis et al. (1972) and manifested by rashes on the scalp and face, similar to seborrheic dermatitis, as well as lichenoid hyperkeratotic papules on the skin of the extremities. There are three types of hyperkeratotic lesions observed in most patients:

1. linear, lichenoid and verruzovye;
2. yellow keratotic foci and
3. slightly raised papules with horny plugs.

There is frequent damage to the palms and soles in the form of diffuse keratosis and individual hyperkeratotic papules, sometimes the nails are affected, they thicken, they are painted in a yellowish color, longitudinal scallops appear on their surface. According to A.N. Mehregan et al. (1984), this clinical form does not correspond to a coral one, but to a vercucous red flat lichen.

Ulcerous form of red flat lichen is also very rare. Ulcerous lesions are painful, especially when localized on the lower limbs, they are small in size with infiltrated edges, reddish-cyanotic color. At the same time in other areas of the skin can be found typical for red flat rash rash.

The pigmentary form of the red flat lichen can be manifested in the form of nodular elements typical for morphology, but having a brownish-brown color, diffuse foci of pigmentation, changes similar to poikilodermic, in which nodular eruptions can hardly be detected. In some cases, typical manifestations of red flat lichen on the oral mucosa are found. A variant of the pigmentary form of red flat lichen is considered by some authors as persistent dyschromic erythema, or "ashy dermatosis", clinically manifested by multiple ash-gray spots, located mainly on the neck, shoulders, back, not accompanied by subjective sensations.

The subtropical form is found mainly in the countries of the Middle East, characterized by pigment-ring-shaped lesions, located mainly on the open parts of the body. Itching is minor or absent, the nails and scalp are rarely affected.

The course of red flat lichen is usually chronic. Elements on the mucous membranes regress more slowly than on the skin. Long-term hypertrophic and erosive-ulcerative foci can be transformed into squamous cell carcinoma.

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Differential diagnosis

Differential diagnosis of red flat lichen is carried out with:

• psoriasis,
• nodular prurigo,
• lichenoid and warty skin tuberculosis.

[8], [9], [10]

Treatment of the red flat lichen

Conducted therapy depends on the prevalence, severity of the course and clinical forms of the disease, as well as on the concomitant pathology. Apply drugs that affect the nervous system (bromine, valerian, motherwort, elenium, seduxen, etc.), hingamic drugs, (delagil, plakvepil, etc.), as well as antibiotics (tetracycline), vitamins (A, C, B, PP, B1, B6, B22,). With common forms and in severe cases, prescribe aromatic retinoids (neotigazone, etc.), corticosteroid hormones, PUVA therapy (Re-PUVA therapy).

External prescribe antipruritic drugs (agitated suspensions with anesthesin, menthol), ointments with corticosteroid hormones (elokom, betnoveit, dermovet, etc.), often applied to the occlusive dressing; verukoznye foci are cured with hingamin or diprospan; in the treatment of mucous membranes used 1% dibunol ointment, rinse with sage infusion, chamomile, eucalyptus.

Forecast

The defeat of the oral mucosa with red flat lichen can persist for many years, and, as a rule, difficult to treat, often recurs.

Atrophic and / or erosive-red form of red flat lichen are associated with a risk of malignant tumors.

[11], [12]