Diffuse skin redness

Introduction The defense response of the living tissue with the vascular system to the injury factor is inflammation. The vascular response is the central link in the inflammatory process. For autoimmune diseases, the cause is associated with a virus or toxoplasmosis infection. Dermatomyositis (DM), also known as skin heterochromic dermatomyositis, is one of the autoimmune connective tissue diseases. It is a non-suppurative inflammatory lesion mainly involving striated muscle and lymphocyte infiltration, which may be accompanied by or Without a variety of skin damage, it can also be associated with various visceral damage.

Cause

The exact cause of the disease is not clear enough. It may be a viral infection, an abnormal recognition of the body's immune abnormalities, and vascular lesions. The three may also be related to each other, resulting in vasculitis and the disease.

(I) Immunological research In view of the increase in serum immunoglobulin, muscle biopsy specimens showed IgG, IgM and C3 in the tiny blood vessels and C56-C9 deposition in the complement membrane attack complex. The degree of deposition seems to be related to disease activity, so it is proposed. Autoimmune disease theory.

(B) sensory theory In recent years, some scholars have observed the muscle and skin lesions of patients with electron microscopy, and found that muscle cells, vascular endothelial cells, perivascular tissue cells and fibroblasts and nuclear membranes have similar mucovirus or secondary adhesion. Particles of the virus. In children with dermatomyositis, there is often a history of upper respiratory tract infection before the onset, anti-streptococcal "O" value increased, antibiotics combined with corticosteroid treatment can be effective, proposed infection allergy theory.

(C) vascular lesions vascular lesions have been described especially in children with DM, any diffuse vascular disease can produce striated muscle ischemia, resulting in individual fiber necrosis and muscle infarct area, in DM / PM special children patients Evidence for endothelial cell damage and thrombus in capillaries, and the deposition of immune complexes in intramuscular vessels, as well as thickening of the capillary basement membrane, especially in the perisome region of the muscle bundle.

an examination

Related inspection

Urinary creatine function test

Biochemical indicators such as creatine phosphokinase, lactate dehydrogenase, aspartate aminotransferase, and alanine aminotransferase in the serum of patients will increase significantly. These are caused by a large amount of muscle fiber necrosis caused by dermatomyositis, and a large amount of enzyme substances in the muscle fibers are released into the blood.

At this time, the amount of creatinine excretion in the patient for 24 hours was also measured, and it was also significantly increased. Creatine is a biochemical substance that is normally produced by the synthesis of the human liver and then ingested by the human muscles to produce muscle energy. In patients with dermatomyositis, the ability of muscle to ingest creatine is greatly reduced due to muscle disease, resulting in a significant increase in creatine content in the blood, which is excreted from the urine through the kidneys, causing a significant increase in creatinine.

Differential diagnosis

Early dermatomyositis: In addition to the eyelids, the skin lesions often involve the entire facial skin, including the frontal, cheeks, ankles, anterior and lower abdomen, diffuse redness, and the entire face is not visible. At this time, gently press the red skin of the face with your finger, which is like the soft feeling of pressing on the rubber block.

Solar dermatitis caused by cosmetic allergies: Although the facial skin is also red and swollen, but carefully observed, the redness and swelling range is limited to the cheeks and lower jaws of both sides. The edges of the erythema are clear, and many normal color skins are visible on the face. The finger gently presses the red skin, which is like the softness of pressing on cotton.

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