This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Immunology and Rheumatology, Subject name: Medicine
[{'content': 'A 10-year-old child has recurrent signs and symptoms of palpable purpura on the buttocks, arthralgias, colicky abdominal pain, diarrhea, and microscopic hematuria. Which of the following is the most likely diagnosis? \nSelect and explain. \nA. influenza, B. immune complex vasculitis, C. juvenile RA, D. systemic lupus erythematosus (SLE)', 'role': 'user'}, {'content': 'Answer: B \nExplanation: The child most likely has Henoch-Schonlein purpura, an immune complex vasculitis affecting the skin, GI tract, and renal glomeruli. Inciting antigens include upper respiratory tract infections, drugs, foods, and insect bites.', 'role': 'assistant'}]