Saw a case in the clinic today of a 40-ish year old woman who was diagnosed about a year and a half ago with Henoch-Schonlein purpura. This is notable in that usually this is a pediatric disease–though as this case illustrates it can certainly affect adults. This particular patient had all three elements of the “classic triad” of HSP: purpuric rash, abdominal pain, and arthritis. In addition, she also experienced renal failure secondary to glomerulonephritis, with a creatinine that had elevated to 2.5mg/dL from a normal baseline and whopping proteinuria with a urine protein:creatinine ratio of >20. Fortunately, with plasma exchange, prednisone, and Cytoxan, her symptoms eventually resolved, and today in the clinic (about 1.5 years after having been initially diagnosed) her creatinine was down to 1.2 mg/dL. The disease appears to lie along the same spectrum as IgA Nephropathy, as renal biopsy of HSP patients is often indistinguishable from that of IgA Nephropathy kidneys: mesangial proliferation with IgA deposits. HSP is best categorized as a vasculitis and it is commonly preceded by an upper respiratory tract infection–it has been linked to Strep infection, viral infection, and even certain medications, though in most cases no underlying etiology causing HSP is identified.