Introduction An infection of the external ear canal caused by excessive moisture Sub category of otitis externa known as necrotizing (or malignant) otitis externa seen most commonly in the diabetic population Pseudomonas aeruginosa is most common etiology an emergency condition can progress to osteomyelitis of the skull base treatment is IV ciprofloxacin Presentation Symptoms puritis pain Physical exam erythematous and edema possible otorrhea purulent discharge worsened my manipulation of pinna Evaluation In diabetics CT/MRI to rule out osteomyelitis Differential Rule out Ramsay Hunt syndrome herpes infection of geniculate ganglia (CN VII) painful vesicles in external auditory meatus Treatment Removal of cerumen from ear canal Treat with antibiotic eardrops Diabetics require hospitalization with IV antibiotics