Image of the Week: Abdominal pain, a rash, and knee pain

A 3-year-old female presents to her pediatrician with a 1-week history of abdominal pain and a rash. Her mother mentions that the rash developed following recovery from an upper respiratory tract infection and that she has also been complaining of knee pain. On examination, a purpuric rash is seen on her legs and feet. Urinalysis reveals hematuria and proteinuria. Learn ...