Polymyositis and Dermatomyositis: A Guide for Patients
Polymyositis and dermatomyositis are both muscle diseases and both involve inflammation. Polymyositis involves the skeletal muscle being inflamed while dermatomyositis is characterized by a skin rash. These two inflammatory myopathies often have an unknown cause, however, some are caused by parasites, viruses, or bacteria.
Symptoms
These two conditions share some common symptoms. These include:
- Difficulty swallowing
- Shortness of breath
The other symptoms of polymyositis include:
- Difficulty speaking
- Mild muscle or joint tenderness
- Fatigue
The other symptoms of dermatomyositis include:
- Muscle weakness
- Upper eyelids being a violet or purple color
- A skin rash that is purple-red
- Muscle soreness or stiffness
The skin rash can appear on the knuckles, shoulders, back, face, neck, and upper chest.
Testing and Diagnosis
Polymyositis and dermatomyositis can both be difficult to diagnose. Certain diagnostic tests are done for both conditions, including:
- Magnetic resonance imaging
- Muscle biopsy
- Electromyography
- Blood testing and analysis
Treating These Conditions
Corticosteroids, such as prednisone, are the most common treatment for both of these myopathies. These drugs are potent anti-inflammatories that suppress the immune system. Most patients will have to take corticosteroids for the rest of their lives. Prednisone is associated with a host of side effects and every patient should be aware of these before starting this drug. The common side effects include:
- Headache
- Insomnia
- Extreme mood changes
- Bulging eyes
- Fragile, thin skin
- Delayed healing of bruises or cuts
- Changes in body fat distribution
- Weak muscles
- Decreased sexual desire
- Increased sweating
- Dizziness
- Inappropriate happiness
- Personality changes
- Acne
- Purple or red lines or blotches under the skin
- Increased hair growth
- Extreme tiredness
- Absent or irregular menstrual periods
- Heartburn
The more serious side effects warrant immediate medical attention and include:
- Vision problems
- Sore throat; chills; cough; fever; signs of infection
- Depression
- Confusion
- Uncontrollable hand shaking
- Upset stomach
- Lightheadedness
- Irregular heartbeat
- Shortness of breath, specifically at night
- Pain or swelling in the stomach
- Difficulty swallowing or breathing
- Hives
- Eye pain, tearing, or redness
- Seizures
- Losing contact with reality
- Muscle tightening or twitching
- Burning/numbness/tingling in the face/feet/arms/hands/legs
- Upset stomach
- Vomiting
- Sudden weight gain
- Dry, hacking cough
- Swelling of the eyes/lips/throat/hands/ankles/face/tongue/arms/feet/lower legs
- Rash
- Itching
If dermatomyositis has an associated tumor, removing the tumor may help in relieving the rash and muscle weakness.
A variety of other treatments exist for polymyositis, including:
- Corticosteroids-sparing agents
- Intravenous immunoglobulin
- Immunosuppressive therapy
- Biological therapy
- Dietetic assessment
- Physical therapy
- Speech therapy
All of these treatments also have their own side effects. If a patient experiences too many side effects, or side effects that are worsening or too severe, with a specific therapy or drug, they should talk to their doctor about reevaluating their treatment plan to either change the treatment or adjust the dose that is given.
Resources
MayoClinic.com. (2009). Polymyositis. Retrieved on August 25, 2010 from MayoClinic.com: https://www.mayoclinic.com/health/polymyositis/DS00334
MedlinePlus. (2009). Dermatomyositis. Retrieved on August 25, 2010 from MedlinePlus: https://www.nlm.nih.gov/medlineplus/ency/article/000839.htm
