Infections of the external ear canal are common and can typically be treated with topical antibiotic solutions (Cortisporin Otic, Cipro Otic, etc...) or antibiotic solutions mixed with topical steroids (Cortisporin HC Otic, Cipro HC Otic, etc...). Most patients should not require PO or IV antibiotics.
However, you need to always be on the look out for malginant otitis externa (MOE) which is a more deep seated infeciton extending into the temporal bone and can have a mortality rate as high as 50%. Patients that are diabetic, immunospressed, or have had radiation therapy to the base of the skull are at increased risk. Patients with MOE typically have pain out of proportion to clinical findings and granulation tissue may be present in the ear canal. Suspect this diagnosis in patients that have cellulitis or extreme tenderness over the mastoid process.
If you suspect MOE the patient should be started on antibiotics that cover pseudomonas. Consider obtaining a CT scan with temporal bone cuts and an Otolaryngology consultation.
