Skin manifestations with dermatomyositis

Dermatomyositis (synonym: polymyositis, Wagner's disease) is a disease of connective tissue that proceeds with a predominant lesion of the skin and skeletal muscles, a severely developing disease of unclear etiology characterized by dystrophic changes, predominantly striated muscle tissue, and skin manifestations. There are cases that occur only with muscle damage. In the pathogenesis of the disease, the main importance is attached to cell-mediated sensitization to various antigens. It develops at any age, including in children, but mostly after 50 years, more often in women.

Causes and pathogenesis of dermatomyositis. There are several theories (infectious, viral, autoimmune) that explain the occurrence of dermatomyositis. Currently, many dermatologists support the autoimmune hypothesis of dermatomyositis, as evidenced by the systemic, sensitized lymphocytes to antigens. Muscle tissue, cytotoxicity of lymphocytes to auto-, homo- and hegeralogical muscle cultures, the presence of antinuclear antibodies, and circulating immune complexes. The presence of family cases, the development of the disease in twins, other connective tissue diseases in families, association with antigens and histocompatibility (HLA D8 and DRW3) allowed scientists to put forward a theory about the genetic predisposition of the disease.

There is paraneoplastic dermatomyositis. The nature of association of dermatomyositis with tumors has not been established. It is believed that the allergic effect of tumor products on the body and the inclusion of immune mechanisms are possible. In the development of dermatomyositis an important role is played by diseases of internal organs, nervous, endocrine systems. Sclerotrophic leichen can be provoked by drugs, infectious diseases, insolation, etc.

Symptoms of dermatomyositis. Dermatomyositis is divided into primary (idiopathic), more often developing in children, and secondary (usually paraneoplastic), observed predominantly in adults, and downstream - to acute, subacute and chronic.

Among the skin manifestations, the most common is edematous erythema with a lilac shade, located mainly on the open parts of the body, especially on the face, the bowl is periorbital, and on the back surface of the hands, neck, upper chest and back. Scolioderm-like changes can be observed on the forearms and the back surface of the hands. Sometimes the rash is polymorphic, which gives the clinical picture a resemblance to systemic lupus erythematosus, especially when antinuclear antibodies and deposits are detected under the epidermal basement membrane of immune complexes. With the long course of the disease, atrophic changes in the skin develop with the phenomena of poikilodermia (poikilo-dermatomyositis). The muscles of the shoulder and pelvic girdle are most often affected. There are soreness, swelling, weakness, atrophy, progressive hypotension, adynamia. When the muscles of the esophagus are affected, swallowing is difficult, breathing is disturbed when the diaphragm muscles are involved in the process.

The disease is often observed in women. The disease in most patients begins with prodromal phenomena. In some patients, the process develops slowly with minor pain in the limbs, malaise and a slight increase in temperature. But it is possible and acute onset of the disease (severe pain, especially in the limbs, headache, dizziness, nausea and vomiting, severe chills with fever to high digits). In most patients, there is edema and redness of the face with a lilac shade, especially in the periorbital region. Erythema is especially pronounced on the upper eyelids and in their circumference (a symptom of "glasses"). Sometimes it takes up the middle part of the face, recalling the "butterfly" of lupus erythematosus. The presence of numerous telangiectasias makes the coloring more saturated.

Erythema and swelling are usually noted on the lateral surfaces of the neck, to a lesser extent - on the extensor surfaces of the upper extremities, the trunk, and sometimes on some other sites. On the extremities, the skin is affected mainly in the area of large muscles and joints. Erythema and puffiness can spread from the neck to the area of the shoulders, chest and back like a pelerine. Relatively rare on the background of redness or outside it there are nodular lichenoid rashes. Against the background of erythema, sometimes there are urtic, vesicular, bullous, papular and hemorrhagic eruptions. There are reports of cases of necrotic changes, erosion and skin ulceration. In some patients, dermatomyositis takes the character of erythroderma ("myasthenic erythroderma" of Milian). Scleroderm-like changes can appear on the hands and forearms. In these areas, the skin is dry, hair loss and nail damage are observed. In the future, the clinical picture of poikiloderma can develop. Approximately 25% of all patients with dermatomyositis have mucosal lesions in the form of stomatitis, glossitis, conjunctivitis, and leukoplakia of the tongue.

Subjective phenomena are usually expressed, very abruptly, but the itching of patients almost does not complain, only in some cases it is intense.

Along with the skin with dermatomyositis, as the name of the disease itself shows, the muscular system is affected, which usually affects at the very beginning. Patients are troubled by progressive muscle weakness, mainly in the proximal parts of the extremities, adynamia. Any muscle can be involved in the process. Patients complain of more or less severe pain, and especially painful is the passive extension of the limbs. Because of the defeat of the skeletal musculature, the gait becomes shaky, it is impossible to keep the head straight, it is difficult to take off your clothes ("shirt symptom"), climb stairs ("a symptom of the staircase"), comb your hair ("comb symptom"). A crying expression is striking, which is the result of the defeat of facial muscles. The face looks badly worn ("carnival mask"), sad ("whiny mood").

When the muscles of the throat are damaged, patients easily choke, aphonia develops when the muscles of the larynx are affected. Over time, the muscles atrophy, they deposited calcium salts, developing contractures. In some patients, rhromatomyositis is clinically manifested only by muscular changes ("polymyositis").

With dermatomyositis, visceral lesions are also observed - the gastrointestinal tract of the upper respiratory tract, bronchus and lungs, myocardium and endocardium, the involvement of the central and peripheral nervous system, tropical disorders of the appendages of the skin, and osteoporosis. Common phenomena often include tachycardia, severe hyperhidrosis, significant weight loss, and increased sensitivity to light.

Usually, accelerated ESR is detected, often - creatinuria, albuminuria, the amount of serum albumin is reduced.

Dermatomyositis is relatively often combined with malignant tumors of internal organs (cancer, much less often - other tumors: sarcoma, leukemia, cervical cancer, etc.).

Elimination of a malignant tumor leads to rapid clinical improvement, and sometimes even to complete remission of dermatomyositis.

Histopathology of dermatomyositis. Changes in the epidermis and dermis resemble those in scleroderma, in part - in lupus erythematosus. With deep biopsy of muscles, transverse striation is not detected. Fragmentation is detected, various types of muscular fiber dystrophy, interstitium - infiltrates, perivascular or diffuse, mainly from lymphoid cells.

Pathomorphology of dermatomyositis. In the skin, the picture can be different depending on the intensity of the process. In the initial stages, mildly expressed perivascular infiltrates of lymphohistiocyte character and capillaritis are noted. In the future, atrophy of the epidermis with vacuolar dystrophy of the basal layer cells, edema of the upper dermis, inflammatory reaction, often with fibrinoid changes around the capillaries and in the region of the dermoepidermal junction develop. In old lesions, there are phenomena of vascular poikilodermia, in which a strip-like infiltrate from lymphocytes and histiocytes is found under the epidermis. The epidermis is atrophic, the epidermal outgrowths are smoothed, in the dermis, it is often possible to see foci of mucinous dystrophy in the form of glycosaminoglycan deposits, more often in places of inflammatory infiltrates. Foci of mucinous dystrophy are also found in the subcutaneous tissue. In later stages of the process, deposits of calcium salts can be observed.

Dystrophic and destructive changes prevail in the affected muscles, the degree of which depends on the severity of the process, which is manifested in the disappearance of transverse striation, the hyalinosis of the sarcoplasm with the proliferation of its nuclei. Sometimes the muscle fibers become unstructured, break up into separate fragments, which are then subjected to phagocytosis. In the interstitium, inflammatory infiltrates of varying degrees are found, consisting of lymphocytes, plasmocytes, histiocytes and fibroblasts. In cases of the most pronounced destructive changes in muscle fibers (infarction), the inflammatory response is enhanced. In this case, the infiltrate cells are located between the affected muscle fibers and around the vessels in the form of significant clusters. Sometimes in muscular fibers with the help of histochemical methods only dystrophic and necrobiotic changes are detected with a sharp decrease and disappearance of the enzyme activity of oxidative metabolism and muscle contraction. In old lesions, there is an atrophy of the remaining muscle fibers, surrounded by a fibrous tissue that sweeps the dead fibers. Interstitium vessels are also involved in the inflammatory process, in an acute period they detect edema of the walls, proliferation of the entheoteliocytes. Sometimes thrombovasculitis. In later stages, sclerosis of the walls with obliteration of the lumens,

Histogenesis of dermatomyositis is not clear. Some authors consider it to be a group of autoimmune diseases, others consider dermatomyositis (the result of the organism's sensitization to various antigens: infectious, bacterial, viral, etc. There is no doubt that humoral and cellular immunity factors take part in the development of the inflammatory reaction.It is assumed that by means of humoral immune factors there is damage to the vessels of the microcirculatory bed with the subsequent development of dystrophic and necrobiotic changes in muscle fibers. The full-scale link of immunity is indicated by the aggregation in the skeletal muscles of activated mononuclear leukocytes, which in culture have a cytotoxic action directed against muscle cells, and are also capable of lymphoblastic transformation .Autoantibodies are detected in almost half of patients with dermatomyositis .. The production of antibodies against myosin and myoglobin, the significance is most likely the result of necrosis of skeletal mice.The pathogenetic role of the heterogeneous group is more likely, although not proven, pulmonary antibodies, such as PM-1 (PM-Scl). Kn, PA-1, Mi-2. In the response of direct immunofluorescence and 35% of cases in the foci of the affected skin, granular deposits of immunoglobulins (IgG, IgM, IgA) and complement in the zone of the dermo-epidermal border are revealed. Inflammatory infiltrates in the dermis are dominated by activated T-lymphopathy-helpers and macrophages with an admixture of single cells of Langerhans.

There is a certain genetic predisposition to the development of dermatomyositis - an association with the antigens of the system HLA-B8 and HLA-DR3, family cases of the disease are described.

K. Hashimoto et al. (1971) discovered by electron microscopy virus-like particles about affected muscle fibers. There are data on the relationship of dermatomyositis with toxoplasmosis. Similar to dermatomyositis syndrome is observed with recessively inherited X-sporulated hypogammaglobulinemia, there may be muscle damage in the drug pathology caused by L-tryptophan, the so-called "eosinophilia-myalgia" syndrome.

Differential diagnosis. The disease should be differentiated from lupus erythematosus, scleroderma, spontaneous panniculitis.

Treatment of dermatomyositis. Assign glucocorticosteroids in a dose of 0.5-1 mg / kg / day. If the dose is ineffective, increase to 1.5 mg / day.

There is a good effect with the combination of prednisolone with aziotioprine (2-5 mg / kg / day in). It is necessary to avoid steroid myopathy, which often develops 4-6 weeks after the start of treatment. A positive result is given by immunosuppressants - methotrexate and cyclophosphamide. There are reports of the effectiveness of iv injection of immunoglobulin in high doses (0.4 g / kg / day for 5 days) in the form of monotherapy and in combination with corticosteroids.

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