Olson, Emily

INTRODUCTION: IgA vasculitis (IgAV) is an immune-mediated systemic vasculitis characterized by palpable purpura, arthralgias, abdominal pain, and renal disease. Approximately 90% of cases occur in children; however, adults are at increased risk for more severe disease. The pathogenesis of IgAV is associated with inflammatory, infectious, autoimmune, and medication triggers, including tumor necrosis factor (TNF) alpha inhibitors. We describe a case of a man with Crohn’s disease (CD) who developed IgAV in the setting of a perirectal abscess, recurrent Clostridioides difficile infection (CDI), and anti-TNF therapy. CASE DESCRIPTION/METHODS: A 20 year old man with ileocolonic Crohn’s disease and perianal involvement, inflammatory arthropathy, and recurrent CDI presented to an outside ED with increased abdominal pain and rash on the extremities, trunk, and soft palate. Medications included etanercept, vedolizumab, and prednisolone. In the ED, the patient was hypotensive and tachycardic. CT abdomen/pelvis noted multifocal active inflammatory disease and a 3.2 cm abscess in the left ischiorectal fossa. He was initiated on broad spectrum antibiotics for septic shock and underwent emergent perirectal drain placement; post-operatively, his shock resolved. He was transferred to our institution for further management. Upon arrival, the patient was hemodynamically stable and remained on broad spectrum antibiotics and high dose prednisolone. Review of systems was notable for worsening abdominal pain and hematuria. Biopsy of the rash demonstrated IgA vasculitis. C. difficile toxin PCR was positive. Repeat urinalysis demonstrated nephrotic range proteinuria and hematuria, consistent with IgA nephropathy. ACE-inhibitor therapy was initiated, and skin lesions gradually improved with topical triamcinolone. DISCUSSION: We report a case of a patient with ileocolonic and perianal Crohn’s disease on TNF-alpha inhibitor therapy who developed IgA vasculitis in the setting of septic shock secondary to perirectal abscess and recurrent CDI. This case highlights anti-TNF therapy, infection and inflammatory bowel diseases as potential causes of systemic vasculitis. A high clinical suspicion is needed in order to obtain an early histopathologic diagnosis for IgAV and prompt evaluation of other organ system involvement.