P046 A Case of Henoch-Schonlein Purpura During Infliximab Treatment for Ulcerative Colitis
Authors: Keeley Melissa , Cloney Deborah , Kammeraad Colin 
Published: December 2019

CASE:
We present a case of a 13-year-old male with ulcerative colitis who developed Henoch Schonlein Purpura while receiving infliximab. Patient was initially diagnosed with ulcerative pancolitis via colonoscopy after development of diarrhea and hematochezia. He was started on mesalamine (Apriso) 1.5 grams daily with initial resolution of bloody stools, normalization of labs and demonstrated good weight gain. About a month later, the patient again developed hematochezia and demonstrated elevation of his fecal lactoferrin. His medication was then changed to mesalamine (Lialda) 4.8 grams daily to increase his mesalamine dose and prednisone was also added. He had temporary improvement of his symptoms for 2 weeks, but then again demonstrated worsening with 6–7 bloody stools/day, vomiting and abdominal pain. At this time, he required hospitalization for IV corticosteroid management. During admission, he failed to show response to IV solumedrol and so was started on infliximab therapy 10 mg/kg/dose. He showed excellent response to infliximab, so after standard induction therapy, the decision was made to continue infusions every 8 weeks. This was subsequently changed to every 6 weeks after his infliximab level was found to be low in the absence of antibodies. He remained stable on infliximab infusions for several months before he again experienced exacerbation of his gastrointestinal symptoms requiring admission to the hospital. Symptoms improved with IV solumedrol and protonix. In response to a second exacerbation the frequency of infliximab infusion was increased to every 4 weeks. Approximately 1 month after this increase in frequency, the patient developed abdominal pain, palpable purpura of bilateral lower extremities from the feet extending to the mid-thigh, and bilateral foot swelling. Urinalysis revealed proteinuria, which resolved in the week following initial evaluation. The purpura continued to spread and extended to the bilateral buttocks and upper extremities. Punch biopsy of the purpuric lesions with immunofluorescence showed evidence of leukocytoclastic vasculitis with strong IgA deposition and weak C3 complement deposition consistent with a diagnosis of HSP. The patient was started on oral corticosteroids and infliximab infusions were discontinued. With this treatment the patient’s skin lesions began to resolve. At the time of writing, the patient’s rash has not recurred and his ulcerative colitis remains in remission on subcutaneous methotrexate. TNFα antagonists are an increasingly common treatment for chronic inflammatory conditions including rheumatoid arthritis, ankylosing spondylitis, psoriasis, psoriatic arthritis, and inflammatory bowel disease. They are generally well-tolerated, however adverse effects include infusion reactions, injection site reactions, psoriatic eruption, cutaneous infection, vasculitis, granulomatous reactions, malignant neoplasm, and lupus-like disorders. While leukocytoclastic vasculitis is a well-described adverse event, there is only a small number of case reports suggesting a correlation between anti-TNFα medications (infliximab, adalimumab, and etanercept) and development of Henoch-Schonlein purpura (HSP). The case we present follows a similar progression to that of other documented cases of HSP with symptoms beginning within 3 months of initiation of therapy or an increase in dose and resolving after discontinuation of the offending agent. Our case adds to the small body of literature linking HSP, a potentially dangerous condition, to infliximab.