What is dermatomyositis?
Dermatomyositis is an autoimmune disease with specific skin findings, which also frequently affects the muscles. Dermatomyositis can be a sign of internal malignancy, with 20% of patients having an associated cancer (ovarian cancer risk, in particular, is elevated). Patients require thorough evaluation for this disease apart from the skin, including examination of the muscles, joints, lungs, and malignancy screening.
Who is at risk to get this disease?
As with many autoimmune diseases, rates are higher in women, but the true incidence is unknown.
What are the signs/symptoms of dermatomyositis?
Hallmark skin findings include:
- Purple/red color of the eyelids which can extend to the face- this rash does not spare the smile lines
- Flatted-topped bumps over the knuckles of the fingers
- Purple/red color on the top surfaces of finger joints
- Thickening of the sides of the fingers
- Ragged, frayed cuticles
- Red blood vessels under the fingernails
- Purple/red color of the V-neck of the chest and upper back/lateral deltoids
- Redness of the sides of hips/thighs
- Sensitivity to the sun
- Itchy redness of the scalp
Patients may present with predominantly skin disease with little or no muscle disease or with more muscle inflammation.
How is cancer related to dermatomyositis?
In adults, 20% of patients with dermatomyositis have an underlying malignancy, and the condition may be the first sign of cancer. All patients with dermatomyositis should undergo a thorough history and review of systems. Patients should undergo age- appropriate malignancy screening as well. Ovarian cancer is strongly associated with dermatomyositis.
How is dermatomyositis diagnosed?
In general, the evaluation of patients with suspected dermatomyositis starts with a thorough physical exam. If the diagnosis is in doubt, a skin biopsy may sometimes be helpful.
All patients should undergo laboratory evaluation for signs of muscle inflammation.