Shaun is a 12 year old boy with erythema and edema over the…

Shaun is a 12 year old boy with erythema and edema over the right periorbital area.  He and his mother think he was bitten by a mosquito yesterday evening.  He felt fine when he went to bed, but this morning he woke up to the right side of his face being puffy and swelling around his eye. Shaun also complains of pain with certain eye movements. On physical examination, the examination of cranial nerves III, IV, and VI that control extraocular movements are abnormal.  You diagnose him with periorbital cellulitis.  What is your treatment plan?