A 5-year-old girl presents with an 8-week history of pain and swelling in the right knee, right shoulder, and left elbow after returning from summer camp. She denies any antecedent trauma, fevers, or rashes. Antibiotics prescribed by her primary care doctor have provided no significant relief, but she reports feeling better at the end of the day. Labs reveal a negative rheumatoid factor. Which of the following is most commonly associated with her diagnosis?