Sweet's syndrome with arthritis in an 8-month-old boy

Sweet's syndrome was diagnosed in a F-month-old boy. He was successfully tr eated with systemic corticosteroids. Al the age of 8 months. he developed a cute arthritis in his right knee. The synovial fluid was analyzed and revea led a very high neutrophil count and neutrophil activation with a detectabl e level of intraarticular granulocyte-monocyte colony stimulating factor (G M-CSF). Prednisone injection into the knee led to dramatic improvement. No recurrence occurred.. Although arthritis and/or arthralgia are common featu res in adult patients with Sweet's syndrome, this is the first reported cas e of Sweet's arthritis in a child.