Malignant otitis externa (MOE) is a severe, invasive and necrotizing infectious disease that starts in the external auditory meatus (EAM) and may progress to the parotid region, mastoid, middle ear and skull base. It affects mainly the diabetic, the elderly and immunosuppressed patients. Main etiological agent: P. aeruginosa. Symptoms: Otalgia, mal-odorous otorrhea and local edema Diagnosis is carried out through anamnesis, clinical exam, finding the germ and complementary exams. Temporal bone CT Scans allows for the identification of MOE erosions and the MRI defines its expansion to the skull base. Although non-specific, ESR (erythrocyte sedimentation rate) is a parameter that measures MOE’s evolution. Differential diagnosis: benign neoplasia of the EAM, malignant neoplasia of the EAM and cholesteatoma. Treatment: IV ciprofloxacin and continue with it orally until HSS normalization.