Dermatomyositis

What is dermatomyositis?

Dermatomyositis is a rare inflammatory disease marked by muscle weakness and a distinctive skin rash. Dermatomyositis is distinguished from juvenile dermatomyositis. Although these two conditions share the same hallmark features, they are separate diseases with a range of additional disease features and complications.

What are the symptoms of dermatomyositis?

Body/skin symptoms of dermatomyositis include:

• Skin rashes on photo-exposed surfaces
• Pruritus of skin lesions, sometimes severe enough to disturb sleep
• Erythema of the mid-face
• Rashes along the eyelid margins
• Rashes on the dorsal hands, particularly over the knuckles
• Changes in the nailfolds of the fingers
• Rashes on upper outer thighs
• Scaly scalp or hair loss

Muscle symptoms of dermatomyositis include:

• Proximal muscle weakness
• Muscle fatigue while active (walking, climbing, rising from a seated position, or reaching for items above shoulders)
• Muscle tenderness

What causes dermatomyositis?

The exact cause of dermatomyositis is unknown, but the disease shares many characteristics with autoimmune disorders, in which the immune system attacks the body.

How is dermatomyositis diagnosed?

Dermatomyositis may be diagnosed based upon a detailed patient history, thorough clinical examination, detection of characteristic physical findings, and certain specialized tests. These tests include:

• EMG
• MRI
• Muscle biopsies
• (CT) scanning
• Chest radiography
• Barium swallow
• Ultrasound of the muscles affected

What treatments are available for dermatomyositis?

The following medications are used in the management of dermatomyositis:

• Corticosteroids (e.g. prednisone)
• Immunosuppressive agents (e.g. methotrexate, mycophenolate mofetil, azathioprine, rituximab, sirolimus)
• Immune globulins (e.g. intravenous or subcutaneous immunoglobulin)
• Antimalarial agents (e.g. hydroxychloroquine, chloroquine)
• Diltiazem
• Colchicine
• Alendronate
• Warfarin

Where can I find out more about dermatomyositis?

• National Organization of Rare Disorders (NORD)
• Medscape
• Mayo Clinic