Question category: Nephrology
A 9 year old presents unwell with a mild fever. He had a cold in the preceding few days and has now developed a purpuric rash on his buttocks and legs. He is also complaining of joint pain. A urinalysis reveals haematuria and proteinuria and bloods reveal acute renal failure and eosinophilia. What is the likely pathological basis of the renal disease, given the likely diagnosis?