Dermatomyositis
Dermatomyositis Symptoms | Dermatomyositis
Diagnosis | Causes of Dermatomyositis | Dermatomyositis
Treatment | Dermatomyositis Cure | Dermatomyositis
Research
Dermatomyositis is an acquired disorder due to inflammation in the muscle
and skin. Children and adults may both be affected and females are more
likely to obtain it than males.
Dermatomyositis Symptoms
The symptoms are weakness, muscle soreness, bumps of calcium deposits
under the skin, and a red, scaly rash on the elbows, knees, chest, and
face. The presence of the rash usually comes before the muscle weakness,
and it helps distinguish the disorder as dermatomyositis. Some patients
with dermatomyositis will have troubles swallowing.
The weakness in dermatomyositis
usually develops slowly over weeks to months although rare cases can
begin over days. This weakness most commonly affects the muscles of the
arms and legs. Patients often notice trouble getting out of chairs or
climbing stairs. It does not typically involve the muscles of the eyes,
heart, or breathing muscles. However the muscles involved in swallowing
can become weak as well. Muscle pain may also be a prominent symptom
since dermatomyositis is associated with inflammation in the muscles.
The rash of dermatomyositis can look very similar to a number of other
rash types and by skin biopsy there is nothing that distinguishes dermatomyositis
from a host of other skin rashes. In its most typical form the rash maybe
reddish and even purplish and extend across the face, chest, fingers
and neck. Some patients may even lose their hair. Clinically the appearance
if often quite characteristic to neurologists, rheumatologists, and dermatologists.
Dermatomyositis Diagnosis
The diagnosis of dermatomyositis begins with a neurologist taking the
patient's history and performing a clinical exam, especially examining
the rashes. A physician who suspects a diagnosis of dermatomyositis may
perform blood tests, an EMG, or a magnetic resonance imaging scan (MRI).
The blood tests reveal elevated levels of enzymes which are found in
muscle. Doctors may check a creatine phoshpokinase (CPK) or an aldolase.
Without elevated levels of one of these enzymes it is very unlikey to
have a diagnosis of dermatomyositis. The EMG test looks at the function
of a patient’s muscles and will reveal evidence for muscle inflammation
and muscle damage. An MRI looks for visual evidence for inflammation
in a group of muscles. It can also be used to choose which muscle to
biopsy.
If these three non-invasive tests suggest a diagnosis of dermatomyositis
then patients should have a muscle biopsy before beginning therapy. A
muscle biopsy is needed in all patients for a definitive diagnosis.
Finally there are a very specific set of blood tests called Myositis
Specific Autoantibodies. These antibodies are found in 20-30% of patients
with dermatomyositis but are important because they can predict the presence
of other associated conditions.
Dermatomyositis Cause
Dermatomyositis is an autoimmune disorder, meaning that a person's white
blood cells which are supposed to fight off bacteria and viruses begin
attacking their own muscles. While we do not know what triggers a person’s
immune system to behave in this way there are many theories that suggest
it is a combination of one’s genetic predisposition and environmental
exposures. People of either sex or any age can get dermatomyositis,
but it is slightly more common in females, and people in middle childhood
and their 20s. It is sometimes associated with other autoimmune diseases
such as lupus, scleroderma, and rheumatoid arthritis. In rare cases it
can be associated with certain types of cancers.
Dermatomyositis Treatment
|
Muscle Fibers on Edge of Fascicles
are Necrotic and Regenerating |
Dermatomyositis is an autoimmune disease and therefore therapy is directed
at altering a patient’s immune system. All of these therapies therefore
have some significant risk of side effects and treatment needs to be
undertaken only with physicians accustomed to using these medications
and to monitoring their side effects. Corticosteroids are often used
as a first line therapy to treat dermatomyositis because they decrease
the muscle inflammation. These can be effective in a matter of weeks.
If corticosteroids are ineffective, other immunosuppressive medications
may be given such as azathioprine, mycophenylate mofetil, cyclosporine,
or methotrexate. Intravenous immunoglobulin has also been shown to be
effective in very refractory cases.
Dermatomyositis Cure
In most people once this disease begins there is no clear way to cure
the disease. There are however several effective treatments which exist
that can improve a person’s muscle strength. In most cases people can
resume their usual level of function. Further research is being done
and it is hopeful that eventually a cure will be found.
Dermatomyositis Research
Related publications by our physicians:
