What the rheumatologist needs to know about skin biopsy.

The skin biopsy plays an important and powerful role in helping diagnose rheumatic diseases that present with cutaneous findings. As the skin is a very accessible organ, and the skin biopsy can be performed quickly as an in-office procedure, the skin biopsy is utilized frequently in patients with rheumatic diseases. However, the more challenging aspects of performing the biopsy, such as identifying the type of biopsy to perform, the site (s) to biopsy, the type of media to use, and the interpretation of histopathologic data are nuanced and require considerable thought. In this review, we discuss the common skin findings in rheumatic diseases and the general indications for skin biopsies in these diseases. We then summarize how to perform various skin biopsy techniques and how to select the biopsy technique. Finally, we discuss important rheumatic disease-specific considerations for skin biopsy, including where to biopsy and how to interpret the pathologic reports.