Part I: Retiform Purpura: A Diagnostic Approach

Retiform purpura is a specific morphology within the spectrum of reticulate eruptions of vascular origin. It develops when blood vessels serving the skin are compromised resulting in downstream cutaneous ischemia, purpura, and necrosis. Identifying retiform purpura is important particularly in the acutely ill patient. It may elucidate the underlying diagnosis, provide prognostic information, and suggest a treatment approach. The differential diagnosis of retiform purpura is vast, reflecting the myriad conditions that can lead to cutaneous vessel wall damage or lumen occlusion. In this article, we give an overview of the differential diagnosis of this cutaneous morphology, provide an approach to workup, and highlight updates in treatment of some of the more common conditions that manifest as retiform purpura.