(Click the link to comment and to vote – voting not working through email, sorry!)

You are seeing a 10 month old infant with one day of fever, purpuric rash, and subcutaneous edema of bilateral extremities. He was seen in the ED one week ago for cough and congestion and diagnosed with a viral URI. At that time, COVID, influenza, and RSV were negative. On exam, his temp is 39.1. He has multiple, scattered, annular, sharply demarcated hemorrhagic plaques, mainly on his cheeks and bilateral extremities, lower > upper. He is otherwise well appearing and remainder of the physical exam is unremarkable. CBC including platelet count, CMP, coags, DIC panel, CRP, UA, and CSF were all normal.

What is the most likely diagnosis?