Dermatomyositis (DM) (synonyms: Dermatomucomyositis; Dermatomucosomyositis; Dermatomyositis; Purple disease; Petges-Cléjat-Jacobi syndrome; Poikilodermatomyositis; Pseudotrichinosis; Pseudotrichinosis; Wagner disease; Wagner polymyositis; Wagner-Unverricht syndrome; White-spotted purple disease; ICD-10-GM M33. 1: Other dermatomyositis) is an inflammatory muscle disease (myositis/muscle inflammation) that also affects the skin (dermatitis/inflammation of the skin). Involvement of internal organs such as the heart, lungs, gastrointestinal tract is also possible.The disease belongs to the collagenoses (chronic inflammatory autoimmune diseases of connective tissue). The immunological reactions here are directed against vascular (affecting the vessels) and muscle fiber proteins.
Dermatomyositis is divided into the following forms:
- Juvenile dermatomyositis (JDM) – occurs in childhood or adolescents; progressive movement restrictions develop, accompanied by pain in up to 50% of cases; extramuscularly, the heart and lungs are affected; associated tumors are found in about 15% of patients before or after diagnosis of the underlying disease.
- Adult (idiopathic) dermatomyositis (with no apparent cause) – adult form.
- Amyopathic dermatomyositis (ADM) – in children and adults.
- Dermatomyositis associated with malignancies (cancers).
- Dermatomyositis associated with collagenoses
Furthermore, special forms exist as well as overlap syndromes, which will not be discussed further.
Approximately 50% of dermatomyositides in adults are associated with tumor disease (paraneoplastic dermatomyositis). Frequently, the carcinomas involve the gastrointestinal tract (gastrointestinal tract), female breast, ovaries (ovaries), uterus (uterus), lung, prostate. Non-Hodgkin’s lymphoma also occurs in association with dermatomyositis. Usually, dermatomyositis heals after removal of the tumor.
Sex ratio:Males to females is 1: 2.Juvenile dermatomyositis affects girls more often than boys.
Frequency peak:Juvenile dermatomyositis: onset of disease is before the age of 18, usually in the 7th to 8th year of life. In adult dermatomyositis, two frequency peaks exist: at 35-44 years of age and at 55-60 years of age.
Dermatomyositis is a rare disease.
The incidence (frequency of new cases) of juvenile dermatomyositis is about 0.2 cases per 100,000 population per year.The incidence of adult dermatomyositis is about 0.6-1.0 cases per 100,000 population per year.
Course and prognosis:In the course of dermatomyositis, myalgias (muscle pain) movement restrictions occur. As appearance is affected by dermatitis, patients also suffer emotionally. The two clinical pictures dermatitis and myositis do not correlate with each other, i.e. the skin complaints can precede the muscle complaints or appear later (in one third of the cases skin symptoms appear first). A causal therapy does not yet exist. The therapy is lengthy, but often leads to an improvement in the quality of life. In the majority of cases, the disease stops after 5 to 10 years. If left untreated, the disease can be lethal. The 10-year survival rate is approximately 84%.
