Dermatomyositis

What Is Dermatomyositis?

Dermatomyositis is a rare inflammatory disease characterized by muscle weakness and a distinctive skin rash. It belongs to a group of conditions called inflammatory myopathies. The condition can affect adults and children, causing progressive muscle weakness that can significantly impact daily activities.¹

Symptoms²

Skin Changes

Heliotrope rash (purple eyelid discoloration)
Gottron's papules (knuckle rash)
V-sign (rash on chest)
Shawl sign (rash on shoulders/back)
Photosensitivity
Nail fold changes

Muscle Symptoms

Progressive proximal muscle weakness
Difficulty rising from chairs
Trouble climbing stairs
Difficulty lifting arms overhead
Muscle pain and tenderness
Fatigue

Other Symptoms

Difficulty swallowing
Lung involvement (interstitial lung disease)
Joint pain
Calcinosis (calcium deposits)

Diagnosis³

Physical examination of skin and muscles
Blood tests (CK, aldolase, myositis antibodies)
Electromyography (EMG)
MRI of muscles
Muscle biopsy
Skin biopsy
Cancer screening (associated risk)

Treatment Options

Medications

High-dose corticosteroids (first-line)
Immunosuppressants (methotrexate, azathioprine)
IVIG (intravenous immunoglobulin)
Rituximab for refractory cases
Hydroxychloroquine for skin

Other Treatments

Physical therapy
Occupational therapy
Sun protection
Speech therapy (if swallowing affected)

Living with Dermatomyositis

Regular follow-up monitoring
Sun protection essential
Gentle exercise when controlled
Energy conservation
Support groups helpful

Prognosis

Variable course
Many respond well to treatment
Some achieve remission
Monitoring for complications important
Cancer screening recommended

References

Dalakas MC. Inflammatory muscle diseases. N Engl J Med. 2015;372(18):1734-1747.
Mammen AL. Dermatomyositis and polymyositis: clinical presentation, autoantibodies, and pathogenesis. Ann N Y Acad Sci. 2010;1184:134-153.
Lundberg IE, Tjärnlund A, Bottai M, et al. 2017 European League Against Rheumatism/American College of Rheumatology classification criteria for adult and juvenile idiopathic inflammatory myopathies. Ann Rheum Dis. 2017;76(12):1955-1964.