ICD codes for this disease: ICD codes are internationally valid medical diagnosis codes. They are found e.g. in medical reports or on incapacity certificates. M33ArtikelübersichtDermatomyositis
- Causes and risk factors
- Examinations and diagnosis
- Disease course and prognosis
The term "dermatomyositis" is composed of the Greek words for skin (derma) and muscle (myos). The ending "-itis" again stands for "inflammation". Accordingly, the term dermatomyositis describes an inflammatory disease of muscles and skin. It belongs to the group of rheumatic diseases and here to the subgroup of collagenoses (diffuse connective tissue diseases).
The inflammatory processes on the muscles and the skin damage these structures, which in turn leads to the classic symptoms. One of these is the appearance of blue-violet skin changes, which is why dermatomyositis is also called "purple disease".
Who is affected by dermatomyositis?
In principle, dermatomyositis can affect anyone. However, there are two age peaks: Most commonly, however, adults fall ill between 45 and 65 years, with women being affected about twice as often as men. The second age peak is between 5 and 15 years ("juvenile dermatomyositis"); Here, too, girls are more affected than boys.
Overall, dermatomyositis is a rare disease. Just one in every 100,000 inhabitants in Germany gets sick each year.
Which forms of dermatomyositis are there?
Depending on the age of the patient, the course of the disease and associated diseases, physicians distinguish between different forms of dermatomyositis:
When Juvenile dermatomyositis one refers to the disease in young people. It begins acutely, and often the gastrointestinal tract is involved. In principle, the juvenile dermatomyositis does not differ from that in adulthood. However, there is one special feature: juvenile dermatomyositis is not associated with tumor diseases, and it is already associated with adult tumors.
The Adult dermatomyositis represents the classic dermatomyositis of the adult.
The Paraneoplastic dermatomyositis is a dermatomyositis that is related to, but not directly caused by, a cancer. This is the case in 20 to 70 percent of all patients. In women, paraneoplastic dermatomyositis is mainly associated with breast, uterine and ovarian cancer, in men especially with malignant tumors in the region of the lungs, prostate and digestive organs.
Sometimes the paraneoplastic dermatomyositis becomes noticeable at the same time as the tumor, in other cases it precedes or follows the cancer. In any case, it is extremely important to look for tumors if dermatomyositis has been detected.
Of the Amyopathic dermatomyositis Doctors, if the typical skin changes show up, but does not show any muscle inflammation for six months. About 20 percent of all dermatomyositis patients have this form of the disease.To the table of contents
The polymyositis is very similar to the dermatomyositis, however, there are no skin symptoms here. More details about this disease can be found in the article Polymyositis.To the table of contents
Dermatomyositis often begins acutely, but sometimes also gradually. The symptoms are characteristic but may vary in severity and composition. Typical are the skin symptoms as well as the complaints in the area of the musculature. In some cases, other organs are also affected, which sometimes leads to serious complications.
At the beginning of the disease sufferers often suffer from general symptoms such as fever, fatigue, weakness and weight loss. Only in the further course then the typical complaints occur. Regarding the appearance of skin and muscle symptoms, there is no specific order. Sometimes the skin symptoms are preceded by muscle weakness, in other cases they only appear later.
Skin symptoms in dermatomyositis
Dermatomyositis is characterized by skin discolorations (erythema), which often appear dark red to blue-violet, but may also appear in a lighter red. They are preferably found on exposed skin areas on the face, neckline and arms. Especially on the eyelids can reddish swelling occur. A narrow hem around the mouth is usually free of discoloration, what physicians call "Shawl signs".
Dermatomyositis often develops redness and sublimeness ("Gottron's sign") on the fingers. Another possible symptom is a thickened nail fold that hurts when pushed back ("Keining sign").
In addition to skin discolouration, scaling of the skin may also occur on the exposed skin areas.
Muscle symptoms in dermatomyositis
In the beginning, dermatomyositis is characterized by muscle pain (especially under stress), and later by a progressive muscle weakness, which mainly affects the body (proximal) of the pelvic and shoulder girdle. Those affected are increasingly struggling with movements involving these muscles, such as lifting their legs while climbing stairs or raising arms to comb them.
In addition, dermatomyositis can also affect the eye muscles, which can result in drooping of the upper eyelid (ptosis) and squinting (strabismus).
If the pharynx and respiratory muscles are also affected, dysphagia and respiratory distress may occur.
All muscle symptoms of dermatomyositis usually occur symmetrically. If the symptoms only show on one side of the body, it is possible that another illness is behind it.
Organ involvement and complications
Dermatomyositis can affect other organs in addition to the skin and muscles, which in unfavorable cases causes dangerous complications. First and foremost here is the possible infestation of the heart and lungs.
In the heart area it can come about as a consequence to pericarditis, heart failure, a diseased enlargement of the heart muscle (dilated cardiomyopathy) or cardiac arrhythmias.
In the lungs, dermatomyositis may cause damage to the tissue followed by pulmonary fibrosis. If the constrictor fails to function properly due to dermatomyositis, the risk of inadvertently inhaling food components increases. This can cause pneumonia (aspiration pneumonia).
The Dermatomyositis can also affect the kidneys or the gastrointestinal tract, which can lead to kidney inflammation or intestinal paralysis (Darmatonie).
In some patients dermatomyositis occurs together with other immunological systemic diseases. These include, for example, systemic lupus erythematosus, systemic sclerosis, Sjögren syndrome and rheumatoid arthritis.To the table of contents
Dermatomyositis: causes and risk factors
The cause of dermatomyositis is still unclear. According to the current state of research, it is an autoimmune disease:
Normally it is the task of the immune system to recognize and fight foreign structures. In this way, pathogens such as fungi, bacteria or viruses can be rendered harmless. It is important that the immune system can distinguish the body's own from external structures.
Exactly this works in the case of autoimmune diseases but not properly. The immune system then suddenly attacks the body's own structures because it mistakenly considers them foreign substances.
The exact mechanisms that cause such a change in the immune system are often still unknown. This also applies to dermatomyositis. But one suspects a hereditary component, so a genetic predisposition to the disease. In people with this predisposition, various factors such as infections (such as with coxsackie, influenza or retroviruses) or medications (such as antimalarials, lipid-lowering or anti-inflammatory drugs such as diclofenac) could trigger the immune system's malfunction and thus the development of dermatomyositis:
Certain parts of the immune system, especially antibodies, target their attacks mainly against small blood vessels that supply the muscles and skin with oxygen and nutrients. This causes damage to these structures with the typical symptoms of dermatomyositis.
Related to cancer
The occurrence of malignant tumors associated with dermatomyositis is significantly increased. The exact reason for this is still unclear, though there are some assumptions (such as that a tumor produces toxins that directly damage the connective tissue). In any case, it is known that after removal of the tumor, the dermatomyositis often heals, but recurs when the cancer progresses.