On awakening in the morning, a 2-year-old girl was noted to have left-sided facial swelling and was brought to the emergency department. The child had had no fever, trauma to the area, pain, or difficulty in swallowing. Her medical history was unremarkable. Her immunizations were up-to-date; she had received both doses of the measles, mumps, and rubella (MMR) vaccine about 6 months before presentation. There were no sick contacts.

For 3 months, a 9-year-old boy had swelling of the left upper arm. An MRI scan obtained at another facility 1 week after onset showed extensive edema of the soft tissue at the midhumeral level. Laboratory results, including complete blood cell (CBC) count and Lyme titer, were normal.

A 38-year-old man had fever and fatigue for the past 6 days and tenderness in the left upper abdominal quadrant for the past 3 days. He also had a facial butterfly rash that had been present for 10 years and a 1-year history of lupus nephritis, treated with prednisone and mycophenolate. He denied respiratory complaints or recent weight loss.