Myositis
Also known as: Inflammatory Myopathy, Dermatomyositis, Polymyositis
Autoimmune inflammation of the muscles causing weakness and elevated muscle enzymes. Includes dermatomyositis and polymyositis. Requires careful workup and immunosuppressive treatment.
Key Facts
- Dermatomyositis has characteristic skin rashes; polymyositis does not
- Myositis can be associated with underlying malignancy, especially in older adults
- Interstitial lung disease is a serious complication affecting up to 40% of patients
- Myositis-specific antibodies help predict disease course and complications
- Physical therapy is essential — muscles must be rebuilt after inflammation control
What is myositis?
Myositis refers to a group of autoimmune diseases that cause inflammation of the skeletal muscles, leading to progressive weakness. The two most common forms are:
- Dermatomyositis — muscle inflammation accompanied by characteristic skin rashes (heliotrope rash around the eyes, Gottron’s papules over the knuckles)
- Polymyositis — muscle inflammation without the skin component
These are serious conditions that can affect the ability to perform basic tasks — climbing stairs, lifting arms, getting up from a chair. Myositis can also involve the lungs (interstitial lung disease), esophagus (swallowing difficulty), and is associated with an increased risk of malignancy, particularly in dermatomyositis.
Symptoms
- Progressive muscle weakness, primarily in the shoulders, upper arms, hips, and thighs
- Difficulty rising from a seated position, climbing stairs, or lifting objects overhead
- Skin rashes (dermatomyositis): purple discoloration around eyes, red rash on knuckles, chest, or back
- Difficulty swallowing (dysphagia)
- Shortness of breath (lung involvement)
- Fatigue
- Joint pain
- Mechanic's hands — rough, cracked skin on the fingers
How we diagnose it
- Blood work — Elevated muscle enzymes (CK, aldolase), myositis-specific antibodies (anti-Jo-1, anti-Mi-2, anti-MDA5, and others), inflammatory markers
- EMG (electromyography) — Detects characteristic patterns of muscle irritability
- MRI — Identifies muscle edema and inflammation; helps guide biopsy location
- Muscle biopsy — Gold standard for confirming diagnosis and distinguishing subtypes
- Malignancy screening — Age-appropriate cancer screening, particularly in dermatomyositis, as myositis can be a paraneoplastic phenomenon
- Pulmonary function tests and CT chest — Screening for interstitial lung disease
How we treat it
- Corticosteroids — High-dose prednisone is typically the initial treatment
- Steroid-sparing immunosuppressants — Methotrexate, azathioprine, mycophenolate; started early to minimize steroid exposure
- IVIG (intravenous immunoglobulin) — For refractory disease or patients who cannot tolerate other therapies
- Rituximab — For severe or refractory cases
- Physical therapy — Supervised rehabilitation is critical to rebuild strength once inflammation is controlled
- Lung disease management — Aggressive immunosuppression for associated interstitial lung disease
- Ongoing monitoring — Muscle enzymes, strength testing, lung function, and cancer screening
At Synergy Rheumatology
Myositis requires methodical workup and close monitoring. Dr. Fellows has a particular interest in interstitial lung disease intersecting with connective tissue diseases — a common and serious complication of myositis. We coordinate with pulmonology and other specialists as needed and manage immunosuppressive therapy throughout the disease course.
Have questions about myositis?
Schedule an appointment to discuss your symptoms, diagnosis, or treatment options with Dr. Fellows.