How to recognize dermatomyositis: skin manifestations of the disease

Dermatomyositis (polymyositis, Wagner's disease) refers to a severe systemic pathology of the connective tissue of unknown etiology with symptoms of predominant damage to the skin and skeletal muscles, occurring with dystrophic disorders. Sometimes the disease occurs only with lesions of muscle tissue. Dermatomyositis can occur at any age, including in children, but more often after the age of 50, mainly in women.

Causes of dermatomyositis and development of the disease

The emergence of this disease is explained by a number of theories - autoimmune, infectious, viral. To date, most experts adhere to the autoimmune cause of dermatomyositis. This hypothesis is supported by systemicity, sensitization of lymphocytes to antigens, muscles, the presence of antinuclear antibodies, immune complexes in the blood, and some other factors. Some data speak of a hereditary predisposition for this pathology.

In the occurrence of dermatomyositis, the pathology of internal organs, nervous, hormonal systems plays an important role.

Symptoms of dermatomyositis

Dermatomyositis can be primary, most common in childhood, and secondary, which occurs predominantly in adulthood. The course of the disease is acute, subacute and chronic.

Skin manifestations of dermatomyositis:

• photodermatitis and "sunny" swelling around the eyes (symptom of "glasses");
• redness and swelling in the middle part of the face, resembling a butterfly symptom; with lupus erythematosus;
• lilac shade, hyperemia of the skin of the face and in the decollete area, red scaly rash in the area of ​​small joints of the hands, redness and peeling of the skin of the palms – the so-called "mechanic's hand".

Rashes are also most often located in the back, shoulders, lower leg, nails. In addition, peeling of the skin at the site of the rash, itching can be observed. There is a specific symptom of Gottron - scaly pink plaques and nodules on the extensor surfaces of the joints of the fingers.

The rash can be varied, similar in clinical symptoms to systemic lupus erythematosus. If dermatomyositis proceeds for a long time, then atrophy of the skin can develop with manifestations of poikiloderma (poikilo-dermatomyositis).

Most often, dermatomyositis manifests itself in the female population. This pathology in many patients begins with a general malaise. In some patients, the process develops slowly with mild pain in the limbs, malaise and a slight rise in the temperature reaction. Sometimes there is an acute onset of the disease (intense pain in the limbs, headache, temperature rise to hyperfibrile, and other signs of intoxication). Multiple subcutaneous hemorrhages contribute to a greater saturation of the skin color.

Redness and swelling are more common on the sides of the neck, shoulders, chest and back, similar to a drape. Sometimes hyperemia and edema are noted in the extensor areas of the upper limbs. In the area of ​​the extremities, the skin is changed to a greater extent in the area of ​​large muscles and joints. Much less often, a nodular lichenoid rash occurs in the area of ​​hyperemia. Against the background of redness, sometimes there are urticarial, vesicular, bullous, papular and hemorrhagic rashes. There are data on cases of necrotic changes, erosion, the appearance of ulcers on the skin. In some patients, dermatomyositis proceeds with the nature of erythroderma ("myasthenic erythroderma" by Milian). Scleroderma-like manifestations occur in the area of ​​the hands and forearms. In these areas, the skin becomes dry, hair falls out, and the nail plates are affected.

Pathological picture in dermatomyositis

In the skin, manifestations may differ and are associated with the severity of pathological abnormalities. At the beginning, the changes are in the nature of mild perivascular infiltrates and capillaritis. Later, atrophic changes in the epidermis occur with vacuolar degeneration of the cells of the basal layer, edema of the upper part of the dermis, an inflammatory reaction, often with fibrinoid changes around the capillaries, in the area of ​​the dermoepidermal junction. In older lesions, manifestations of vascular poikiloderma are noted, when a strip-like infiltrate of lymphocytes and histiocytes is found under the epidermis. The epidermis becomes atrophic, the epidermal outgrowths are smoothed, in the dermis one can often see foci of mucinous degeneration with deposits of glycosaminoglycans. Areas of mucinous degeneration are also observed in the subcutaneous tissue.