Dr. Jennifer Soung discusses highlights from her lecture Pearls in Derm-Rheum Collaboration on Thursday, November 9, 2023, at the 4th Annual Elevate-Derm PA/NP Conference in Coachella Valley, CA.

In this video

Dr. Soung explains that she collaborates with rheumatology "all the time," and that dermatology clinicians hold a unique advantage: they can see the skin clues that point toward a connective tissue disease and take an easily accessible biopsy to help their rheumatology colleagues. Her repeated pearl is to "biopsy that rash at its worst"—targeting the most prominent erythema or thickest plaque, since skin signs in these diseases can be subtle or non-specific and inflammation is easier to find on histology. When a biopsy comes back suspicious for dermatomyositis, she says it's perfectly reasonable to simply refer, but she likes to start with a few labs—liver function tests, aldolase, LDH, and creatine kinase—to confirm she's on the right track, holding off on the full antibody panel depending on systemic symptoms such as muscle weakness.

She notes that biopsying off the face is equally diagnostic when there are findings elsewhere (holster sign, shawl sign), and reminds clinicians that dermatomyositis histology is far more subtle than lupus, where a classic malar rash is much more prominent. On the common scenario of an incidentally positive ANA, she stresses looking carefully at the rash itself—papules, pustules, greasy scale, and distribution—pointing out that the classic malar rash of lupus spares the nasolabial fold.

  • Collaborate early and often with rheumatology—dermatology's advantage is seeing the skin clues and being able to biopsy easily.
  • Biopsy the rash "at its worst," targeting the most prominent erythema or thickest plaque to capture the interface dermatitis.
  • For suspected dermatomyositis, an initial lab panel of LFTs, aldolase, LDH, and creatine kinase helps confirm you're on the right track; antibodies and full workup can follow or be deferred to rheumatology.
  • Biopsying off the face is equally diagnostic when other findings are present; remember DM histology is more subtle than lupus.
  • With an incidental positive ANA, read the rash carefully—morphology and distribution matter, and the classic lupus malar rash spares the nasolabial fold.