Imaging features are consistent with necrotizing otitis externa with spreading infection to the parotid and masticator space. The depressed immune status post recent chemoradiotherapy is a risk factor for necrotizing otitis externa in this patient. 

Unenhanced CT head and neck was performed given the patient had previous anaphylactic reaction to intravenous iodinated contrast. Ideally in cases of suspected necrotizing otitis externa contrast enhanced CT should be performed in the absence of contraindication.