A Scholarly Review of NEJM Case 14-2017: A 20-Year-Old Man with Pain and Swelling of the Left Calf and a Purpuric Rash

Background: IgA vasculitis is characterized by a classic tetrad of purpura, joint pain, abdominal pain, and renal involvement. The incidence in adults is 0.8-1.8/100,000. Case Information: A 20-year-old male presented with a two-week history of left calf pain with swelling and purpura. The patient's history was significant for Crohn's disease, for which he took adalimumab. Additionally, the patient had a recent upper respiratory infection. A skin punch-biopsy demonstrating immunofluorescence with IgA, C3, and fibrin was instrumental in confirming the clinical diagnosis of IgA vasculitis. IgA vasculitis is commonly triggered by infection or medication. Anti-TNF-alpha medications not only predispose the patient to infection, but studies suggest they trigger IgA vasculitis. The patient's symptoms of purpura, non-erythematous asymmetric swelling, and lower extremity joint pain are also consistent with the diagnosis of IgA vasculitis. Conclusions: The positive impact of this study is two-fold. First, this case highlights how the diagnosis was missed early in the disease course. Early diagnosis and treatment are essential to preventing further complications including intussusception and glomerulonephritis. Secondly, the patient's presentation is unique, as he did not present with the abdominal pain or renal involvement classically associated with IgA vasculitis. By studying this case with an experienced rheumatologist, we acquired skills such as weighing differential diagnoses and collecting a thorough history. More specifically, we learned about the importance of long-term management to prevent glomerulonephritis, as well as the proper use of glucocorticoids as treatment for IgA vasculitis.