Dermatomyositis is a rare muscle disease that is associated with a skin rash, and we classify it into a group of muscle diseases called inflammatory myopathies.
| Type | Definition |
| Dermatomyositis (DM) | Inflammation of the voluntary muscles associated with skin rash |
| Polymyositis (PM) | Myositis without rash |
| Juvenile DM / PM | Myositis and skin rash that occurs in children under 18 years of age |
| Amyopathic DM | A typical rash that develops without evidence of muscle disease (weakness) |
Types of inflammatory myopathies
Who suffers from dermatomyositis?
Dermatomyositis can affect people of different races of age or gender although it is twice as common in women than in men. The onset of the disease is most often between the ages of 50 and 70 years.
What are the characteristics and symptoms of dermatomyositis?
In many cases, the first sign of dermatomyositis is the presence of itching or an inflammatory rash.
- Redness or bluish-purple spots, especially on sun-exposed parts of the body
- Purple eyelids that are described as heliotropebecause they look like helioitropic flowers
- Purple spots on the bony protrusions of the (especially) fists, called Gotron’s papules
- Rough cuticle and prominent blood vessels at the edge of the nail
- The red rash can affect the cheeks, nose, shoulders, upper chest and folds
- Scaly scalp and thinning, elongated hair may appear.
- Poikilodermaoccurs less frequently
What is poikiloderma?
In poikiloderma, the skin is atrophic (pale, thin), red (dilated blood vessels) and brown (post-inflammatory pigmented).
Are there any other symptoms of dermatomyositis?
Some people, especially children and adolescents, develop a hard yellow or white bulge under the skin called calcinosis, which usually appears on the fingers or above the joints. Sometimes these nodules can penetrate the skin and can become infected. Some patients have swollen joints and Raynaud’s phenomenon (this term refers to fingers that are very pale and stiff in cold conditions, and purple when they come back to warm conditions).
Pictures of complications of dermatomyositis:
A skin rashmost often (but not always) develops before muscle weakness develops. Muscle weakness may occur at the same time as the rash but may occur months or years later.
When can we suspect dermatomyositis?
As the first sign, the proximal muscles are most often affected, that is, the patient cannot close the fist. Difficult daily mobility also indicates the first signs of myositis.
What other functions are impaired in dermatomyositis?
- Climbing the stairs
- Getting up from a sitting or bent position
- Lifting objects
- Raising the arms above the shoulders e.g. combing the hair
- Difficulty swallowing (dysphagia)
Occasionally affected muscles ache and become sensitive to touch
Which diagnostic tests are recommended?
The diagnosis of dermatomyositis is usually confirmed with the following tests.
Blood tests to detect elevated circulating muscle enzymes are:
- Creatine kinase (CK) and sometimes aldolase,
- Aspartate aminotransferase (AST)
- Lactate dehydrogenase
Blood tests for autoantibody detection:
- Nonspecific antinuclear antibodies (ANAs) were found in most patients,
- Specific Anti-Mi-1 was found in a quarter of patients and
- Anti-Jo antibodies are found in several patients usually in those who have lung disease.
Skin biopsy: The microscopic appearance is similar to lupus erythematosus
A biopsy of the affected musculature
Electromyographic(EMG) tests
Magnetic resonance imaging (MRI) search of muscles
To this should be added testing for tumor markers for the purpose of searching for tumors.
What are the causes of dermatomyositis?
Dermatomyositis is classified as a connective tissue disease such as systemic scleroderma and lupus erythematosus. Why dermatomyositis occurs remains unknown, but researchers take it upon themselves to determine the factors that may play a role in its occurrence. Some of them are as follows:
- Genetic predisposition
- Tumors of internal organs (much more common in adults)
- Autoimmune defect (immune reaction against oneself)
- Infectious or toxic agents that act as a trigger
- Drugs that induce dermatomyositis (implied drugs include hydroxyurea, penicillamine, statins, quinidine, and phenylbutazone)
How to treat this nasty disease?
The main purpose of treatment is to control skin changes and muscle weakness. Oral corticosteroids such as prednisonein high doses are the mainstay of medical therapy and are given to slow the progression of the disease. Immunosuppressants or cytotoxic drugs may also be used including methotrexate, azathioprine, cyclophosphamide, cyclosporine, mycophenolate, and high doses of intravenous immunoglobulins.
What else can help treat dermatomyositis?
Medications to treat dermatomyisitis include:
- Diltiazem, a calcium channel blocker commonly prescribed for high blood pressure can reduce calcinosis
- Colchicine can also be used to reduce calcinosis
- Hydroxychloroquine may reduce photosensitivity rash
Some measures that help are:
- Avoiding strong sun exposure and using sunscreen including sunglasses that minimize the harmful effects of the sun
- Lying in bed with severe muscle inflammation
- Physical therapy and activity to preserve muscle and joint mobility
- People who are lying down and have difficulty swallowing due to muscle weakness should have their headboard raised
Conclusion
Most patients will find the right treatment for life, but only about 20% of them. Patients with dermatomyositis who have heart or lung problems or have a tumor of the internal organs, if not treated or not noticed in time, may eventually die from these diseases.
Key words: Dermatomyositis, autoimmune disease, muscle weakness, rash, tumors, prednisone
In short: Dermatomyositis is a disease of unknown origin, and its features are a red or bluish-purple rash and muscle weakness. The causative agent is unknown, but is thought to be of autoimmune origin or related to tumors of internal organs. It is most often treated with prednisone.
Did you know:that SHARP syndrome is a syndrome with overlapping clinical features of systemic lupus erythematosus, scleroderma, polymyositis and Raynaud’s phenomenon. The disease is characterized by a high serum antibody titer of ribonucleic – sensitive nuclear antigen and a variegated epidermal nucleus that is proven by screening called immunofluorescence.
Ante Perica, MD dermatovenerologist
