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

A 19 year old otherwise well-appearing man presents with 2 days of headache, anorexia, tactile fever (but afebrile in the ED), and 1 day of palpable purpura on bilateral lower legs. Which of the following is true?

19yo well appearing palpable purpura on legs - which is true?