A boy with swollen and painful hands

A 6 year old boy presented to the dermatology department with a two day history of progressively swollen and painful hands and wrists. He had no fever, abdominal pain, or knee or ankle swelling or pain. Topical corticosteroid and mupirocin ointment were initially prescribed for possible insect bites, but there was minimal improvement. He had a history of upper respiratory tract infection five days before the hand swelling. He had no other medical history or relevant family history.