Swollen toes.

A 15-month-old black male was brought to the pediatric emergency department by his grandmother because she was concerned about his 2 swollen big toes. The patient's grandmother said that the swelling began 36 hours prior and that her grandson's big toes had continued to increase in size. She denied trauma, bites, or unusual exposures and said that although her grandson had been fussier than usual that day, he was eating and drinking normally and had normal urine output. What is your diagnosis? How would you treat this patient?