eng Science and Education Publishing American Journal of Medical Case Reports 2374-216X 2024-07-11 12 7 93 96 10.12691/ajmcr-12-7-1 AJMCR20241271 article Hiro Matsukura matsukura@5x2.de 1 Shokei Murakami 2 Department of Pediatrics, Saiseikai Takaoka Hospital, Takaoka, Japan Department of Pediatrics, University of Toyama, Faculty of Medicine, Toyama, Japan IgA vasculitis is the most common childhood vasculitis. Subcutaneous edema of the extremities is a common finding in IgA vasculitis, but posterior lumbar subcutaneous edema is a rare complication. A four-year-old boy presented to the emergency department with sudden onset of low back pain, swelling, and refusal to walk. The patient had no history of obesity, spinal trauma, or cardiac, hepatic, or renal dysfunction causing the edema. No prior infection was confirmed. The spine was tender to palpation and swollen over the thoracolumbar vertebrae. Arthralgias of the knees and ankles with a purpuric rash on the lower extremities confirmed the diagnosis of IgA vasculitis. There was no abdominal pain and the urinalysis was normal. Normal plasma factor XIII activity may reflect mild disease or the absence of abdominal pain. The posterior lumbar subcutaneous edema improved immediately with acetaminophen. The leakage of blood vessels into the surrounding tissues due to the vasculitic inflammatory process may result in the posterior lumbar subcutaneous edema. We conducted a literature review of previous case reports of posterior lumbar subcutaneous edema. Most of the patients presented directly to the emergency department and refused to ambulate. None of the patients had superimposed petechiae and purpura over the thoracolumbar spine. All but one patient received corticosteroids or nonsteroidal anti-inflammatory drugs. Lumbar pain and swelling improved completely without recurrence. Posterior lumbar subcutaneous edema in the setting of IgA vasculitis was rare and was a self-limiting symptom of limited duration. https://pubs.sciepub.com/ajmcr/12/7/1/ajmcr-12-7-1.pdf Henoch-Sch?nlein purpura IgA vasculitis plasma factor XIII posterior lumbar subcutaneous edema