Sonographic Findings of Arthralgia in Children with Henoch-Schönlein Purpura

Background Arthralgia is a common manifestation in children with Henoch–Schönlein purpura (HSP). No ultrasonographic (US) findings of arthralgia in patients with HSP have been reported. We therefore investigated these findings in affected joints of children with HSP. Methods The medical records of patients with HSP and arthralgia at Gyeongsang National University Hospital from 2014 to 2018 were reviewed for clinical data about arthralgia, anatomic location, US findings, treatment, and duration of improvement. Results Thirty-one patients underwent joint US imaging. Sixteen patients (51.6%) were aged 2–5 y, 10 (32.3%) were aged 6–10 y, and 5 (16.1%) were aged 11–17 y. Nineteen (61.3%) were boys and 12 (38.7%) were girls. The joint most commonly affected was the ankle (n = 25), followed by the knee (n = 6) and the foot or elbow. Four patients complained of knee and ankle pain simultaneously. Swelling, limited range of motion, tenderness, erythema, and febrile sensation in affected joints were observed in 22 patients (71.0%), 9 (29.0%), 21 (67.7%), 25 (80.6%), and 6 (19.4%), respectively. US images showed no visible joint effusion and no evidence of arthritis or synovitis, but it did show subcutaneous swelling with increased echo around affected joints. Arthralgia improved spontaneously in 6 patients and with corticosteroids in 25. Improvement in arthralgia lasted a mean of 1.9 ± 1.8 days. Conclusion US images showed subcutaneous edema around joints with neither joint effusion nor synovial inflammation.