Causes and risk factors
The female sex is more often affected by the disease. Occurs in young adulthood, dermatomyositis can also be of a child form. Quite often, dermatomyositis in adults is associated with the presence of neoplasms.
The causes of inflammation are unknown.
Which are the symptoms?
Severe muscle weakness, especially in the arms and thighs, sometimes accompanied by pain, sometimes even fever and joint damage with arthralgia and arthritis.
Less common are heart problems, which are manifested by rhythm disturbances and rarely by heart failure. Lung damage leads to fibrosis of the organ.
Tests usually show changes in muscle tissue enzymes (creatine kinase, aldolase).
In the case of dermatomyositis, the skin is also affected:
- lesions are mainly represented by erythema purpurea on the face, especially around the eyes;
- erythematous rashes localized on the extensor surface of the elbows, knees, metacarpophalangeal and proximal interphalangeal joints.
How is it diagnosed?
The diagnosis is based on electromyography and muscle biopsies, which show changes associated with muscle pain. Histological examination shows inflammation of the muscle tissue with infiltration of lymphocytes, degeneration and necrosis of myofibrils.
The presence of characteristic autoantibodies (anti-Jo1) facilitates the diagnosis.
How is it treated?
Cortisone is used, often in combination with immunosuppressants (azathioprine, methotrexate). Skin lesions in dermatomyositis are sometimes well treated with synthetic antimalarial agents (hydroxychloroquine).