– When she brings up dermatomyositis in the context of dermatology, Alisa Femia, MD, often hears from trainees and medical students who assume that this is a condition for rheumatologists to diagnose and treat. That’s not true: Dermatologists need to watch for this potentially fatal connective tissue disorder because they may see it first, she said at Skin Disease Education Foundation’s annual Las Vegas Dermatology Seminar.

“A fifth are clinically amyopathic,” and they may not initially see a rheumatologist, said Dr. Femia, director of inpatient dermatology at the department of dermatology, New York University. “They have normal muscle enzymes and no muscle weakness. It really puts them in our care as dermatologists.”

The challenge is that patient presentations can be subtle, but the stakes may be high, she added. “If we catch them early and treat some of these patients aggressively, we can save their lives.”

During the presentation, Dr. Femia provided these pearls for diagnosing dermatomyositis:

  • Don’t rely on tests like biopsies to absolutely tell you what’s going on. “Clinical examination is the most important test to establish the diagnosis,” she said. “If you’re suspecting dermatomyositis ... get the patient in a gown [for a full-body exam] and look for all the signs that might not be as prominent as they are in our textbooks.”
  • Look for the “butterfly” rash on the midface that is unique because it spares the nasolabial folds. “It looks like someone took an eraser and wiped out those areas,” Dr. Femia said. “This is important to help us nail down the diagnosis.”
  • Other telltale signs, she said, include erythema on the extensor surfaces of digits, severe itching in the scalp, and a rash on the eyelids.
  • Be aware of pulmonary involvement, including interstitial lung disease. In some cases, patients and their physicians wrongly believe that patients with dermatomyositis have asthma or pneumonia. “Pulmonologists are not necessarily aware of lung disease associated with dermatomyositis,” she said.

It’s wise to refer patients with dermatomyositis for malignancy and lung disease screening even if they don’t show signs of muscular involvement. “There’s no significant difference in rates of malignancy or lung disease in classic versus amyopathic dermatomyositis.”

Keep the MDA5 form of dermatomyositis in mind, Dr. Femia said. Anti–melanoma differentiation–associated gene 5 dermatomyositis is linked to rapidly progressive interstitial lung disease, alopecia, arthritis and oral lacerations. “Initially, it can have features of lupus, and the patient can be on immunosuppressive therapy, which mitigates diagnostic findings.”

Dr. Femia disclosed serving as principal investigator for a clinical trial in cutaneous dermatomyositis therapy.

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