Polymyositis & Dermatomyositis
Expert diagnosis and personalized treatment at Arthritis Care of Los Angeles.
What is Polymyositis & Dermatomyositis?
Polymyositis and dermatomyositis are rare inflammatory myopathies — autoimmune conditions that cause chronic muscle inflammation and progressive muscle weakness. Polymyositis primarily affects the skeletal muscles closest to the trunk of the body, including the hips, thighs, shoulders, and upper arms. Dermatomyositis shares these muscle symptoms but also produces distinctive skin rashes, including a violet-colored rash on the eyelids and red, scaly patches over the knuckles, elbows, and knees. These conditions can significantly impact daily life by making activities like climbing stairs, lifting objects, getting up from a chair, or raising your arms overhead difficult. In some cases, the muscles involved in swallowing and breathing can also be affected. Both conditions are also associated with an increased risk of interstitial lung disease and, in adults with dermatomyositis, certain cancers. Dr. Forouzesh at Arthritis Care of Los Angeles provides comprehensive evaluation and management of inflammatory myopathies at our Culver City and Encino locations. Through careful assessment, targeted testing, and individualized treatment plans, Dr. Forouzesh helps patients manage symptoms, preserve muscle strength, and monitor for associated complications.
Common Symptoms
- Progressive weakness in the muscles closest to the trunk (proximal muscles)
- Difficulty climbing stairs, rising from a seated position, or lifting arms
- Heliotrope rash — a violet or dusky red discoloration of the eyelids (dermatomyositis)
- Gottron papules — red or violet bumps over the knuckles (dermatomyositis)
- Difficulty swallowing (dysphagia)
- Muscle tenderness and aching
- Fatigue and general weakness
- Shortness of breath or dry cough (if lungs are involved)
Experiencing these symptoms? Get expert care today.
How is Polymyositis & Dermatomyositis Diagnosed?
Diagnosing polymyositis and dermatomyositis involves a combination of clinical evaluation, laboratory testing, and sometimes muscle biopsy. Dr. Forouzesh begins with a thorough physical examination assessing muscle strength and skin findings. Blood tests measure levels of muscle enzymes such as creatine kinase (CK) and aldolase, which are typically elevated when muscles are inflamed. Myositis-specific antibodies (including anti-Jo-1, anti-Mi-2, anti-MDA5, and others) help identify the specific subtype and guide treatment decisions. Electromyography (EMG) can detect patterns of muscle inflammation, while MRI may show areas of active muscle inflammation. A muscle biopsy may be performed to confirm the diagnosis and distinguish between polymyositis and dermatomyositis. Cancer screening is also recommended, particularly for adults with dermatomyositis.
Treatment Options
High-Dose Corticosteroids
Prednisone is typically the first-line treatment to rapidly reduce muscle inflammation and halt further damage. Doses are gradually tapered as symptoms improve.
Immunosuppressive Medications
Methotrexate, azathioprine, or mycophenolate are often added early to control the disease and allow corticosteroid dose reduction.
Intravenous Immunoglobulin (IVIG)
IVIG therapy may be used for patients with severe or refractory disease, particularly those with dysphagia or skin involvement that does not respond to other treatments.
Biologic Therapies
Rituximab and other targeted therapies may be considered for patients who do not respond adequately to conventional immunosuppressive treatment.
Physical Therapy and Rehabilitation
A structured exercise program is essential for rebuilding and maintaining muscle strength once inflammation is controlled. Physical therapy is tailored to the patient's current abilities.
Key Statistics
5-10
Cases per million adults annually
Source: NIH/NIAMS
2x
More common in women than men
Source: Myositis Association
40-60
Peak age of onset in adults (years)
Source: American College of Rheumatology
Frequently Asked Questions
Ready to Get Expert Care?
Schedule your appointment with Dr. Solomon Forouzesh, MD, FACP, FACR — a board-certified rheumatologist with 50++ years of expertise in arthritis and autoimmune diseases.