LAUSR

A previously well 2-month-old boy presented with a 24-h history of fever, irritability and swelling over the left posterior scalp. This was preceded by the appearance of pustular lesions over the area 5 days earlier. He was born by elective caesarean section; there was no history of trauma. On examination, there was a warm, boggy swelling to the left parietal scalp extending to the occiput. The peripheral white cell count was elevated (22.7 10/L) with neutrophilia (14.0 10/L). C-reactive protein was elevated (101 mg/L). A magnetic resonance imaging head was performed (Fig. 1). What is the most likely diagnosis? (Answer on page 732) Fig 1 Chest X-ray demonstrating cavitary lesions in both lungs (white arrows).