<prompt> Malignant otitis externa is caused by:StreptococcusPseudomonasStaphylococcusMalignancy  <response>: Ans: b Pseudomonas Ref: Dhingra, p. 67 4th ed, p. 52Malignant otitis externa Invasive otitis externaAetiology: Pseudomonal infectionSusceptible: Diabetes patients on immunosuppressive drugsCF: Nocturnal earachePurulent otorrhoeaGranulations in the meatusComplications: Skull base osteomyelitisMultiple cranial nerve palsiesSigmoid sinus thrombosisI.O.C: Diagnostic inv - Tc 99 scanPrognostic inv - Gallium scanTreatment: Antipseudomonal antibiotics - 3rd generation cephalosporins x 6-8 wksTicarcillin, TobramycinOther important external ear conditions frequently asked are:Otomycosis keratosis obturansOtomycosis:Aetiology: Aspergillus niger. Asp. Fumigatus, Candida albicansCFOtoscopic: Itching, watery discharge from ear with musty odour finding: Wet cotton appearance, tissue paper appearance.Treatment: Eartoilet by syringing, suction or mopping Keep the ear dryAntifungal agents-- nystatin, clotrimazoleKeratosis obturans:Collecion of pearly white mass of desquamated epithelium in deeper meatusPathology: Failure of migration of normal epithelium of TM, onto post. Meatal wallCollection of pearly white masses of desquamated epitheliumBone resorptionFacial nerve exposure and paralysisTreatment: Keratotic mass removed by syringing or instrumentationRecurrence - Keratolytic agents like 2 salicylic acid in alcohol 