This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Kidney, Subject name: Pediatrics
A child develops non-blanching macules and papules on lower extremities, mild abdominal pain and skin biopsy showed IgA deposition. Most appropriate diagnosis is: 
Select and explain. 
A. Drug induced vasculitis, B. Henoch Schonlein purpura, C. Wegener's granulomatosis, D. Kawasaki disease
B: Henoch Schonlein purpura
Answer: B: Henoch Schonlein purpura 
Explanation: b. Henoch Schonlein purpura(Ref: Nelson's 20/e p 1612, Ghai 8/e p 632)Classification criteria for H.S. purpura according to Pediatric Rheumatology European Society:Palpable purpura (in absence of coagulopathy or thrombocytopenia) and 1 or more of the following criteria:Diffuse abdominal painArthritis or arthralgiaBiopsy of affected tissue demonstrating predominant IgA depositionRenal involvement (proteinuria, hematuria or red cell casts)Hence, it is a typical case presentation of Henoch-Schonlein purpura.