2550 Henoch-Schönlein Purpura Mimicking Crohn's Disease in a 65-Year-Old Male

Abstract

INTRODUCTION: Henoch-Schönlein purpura (HSP) is a small vessel vasculitis typically seen in children, often presenting with abdominal pain, purpuric rash, arthritis, and hematuria. Also known as immunoglobulin A (IgA) vasculitis, it is mediated by the deposition of immune-complexes containing IgA in the skin, gut and kidneys. Although rarely seen in adults, adult cases are associated with a more severe course than in pediatric patients. We present the case of adult-onset HSP with GI involvement. CASE DESCRIPTION/METHODS: A 65-year-old retired male dairy farmer with recent travel to Southwest US presented with a 6-week history of abdominal pain in the setting of a subacute, diffuse, purpuric rash. After admission, computed tomography (CT) imaging revealed ileitis with fat stranding and mesenteric vascular engorgement, concerning for Crohn's disease (Figure 1). Patient was also found to have proteinuria and arthralgia. Stool infectious work-up was unrevealing. Skin biopsy of the rash identified leukocytoclastic vasculitis and IgA deposition. Patient then underwent colonoscopy with ileoscopy, which scattered areas of congested appearing mucosa with deep purplish discoloration surrounded by normal mucosa (Figure 2). Scattered, nonspecific, rare small erosions and focal erythema were also seen throughout colon and rectum (Figure 3). Biopsies indicated mildly active ileitis and focal areas of active colitis with foci of hemorrhage in the right and transverse colon; there was no evidence of chronicity. Though non-specific, histologic findings were consistent with IgA vasculitis, rather than Crohn's. Patient was started on intravenous (IV) steroids and azathioprine. His rash and abdominal pain improved considerably after 48 hours of treatment. DISCUSSION: HSP, although more common in children, can be seen in adults, and should be included on the differential diagnosis when abdominal pain and/or GI bleeding is seen with concurrent skin, renal, & musculoskeletal findings. HSP is associated with significant morbidity and mortality due to the rapid progression of the disease and recognition can be delayed, particularly in adults. This case of adult-onset HSP was quickly diagnosed and treated with appropriate anti-inflammatory therapy. HSP can mimic Crohn's disease, by history and imaging, but the endoscopic findings are very different. The case illustrates some of the endoscopic and radiographic findings of HSP, promoting awareness among adult gastroenterologists.