A 40-year-old male presents with left ear discharge and mild ear pain for the past 7 years. There is no history of deafness. On examination, the tympanic membrane is intact and discharge is seen coming from the posterior superior wall. The left ear canal and tympanic membrane is normal. Which of the following is the most likely diagnosis?

Ans. b. Chronic otitis externa (Ref: Dhingra 4th/105-106, 54)Chronic Otitis ExternaChronic otitis externa is ac chronic infection/inflammation involving the skin lining of the external canal.There is thickening of skin lining of the external canal due to persistent low grade infection/inflammation.Etiolgy:Caused primarily by repeated local irritation, most commonly arising from persistent drainage from a chronic middle ear infection.Other causes of repeated irritation, such as insertion of cotton swabs or other foreign objects into the ear canal, can lead to this condition, as can rare chronic infections such as syphilis, tuberculosis, and leprosy.Clinical Features:Unrelenting pruritus, mild painPresence of dry skin in the external canalAsteatosis (lack of cerumen), hypertrophic external canal skin, presence of dry flaky skin in the external canalMild tenderness on ear manipulationRarely mucopurulent otorrheaManagement:Treatment: Extensive use of acetic acid ear drops helps to reduce the pH of skin lining the external canal making it more resistant to bacterial infections.Surgery is indicated in extreme cases. A canaloplasty is performed to widen the external canal. The involved skin may be removed to be replaced by a split thickness graft.Carcinoma External Auditory CanalMost commonly squamous cell carcinomaMost commonly seen in cases of long standing ear dischargeMay arise primarily from the meatus or a secondary extension from the middle ear carcinomaClinical Features:Blood staining of hitherto mucopurulent or purulent discharge and severe headacheExamination:Ulcerated area in the meatus or a bleeding polypoidal mass or granulationsFacial nerve may be paralysed because of local extension of disease through posterior meatal wall or its spread into middle earRegional lymph nodes (preauricular, postauricular, infra-auricular and upper deep cervical)Treatment:En-bloc wide surgical excision with post-operative radiation.Keratosis ObturansCollection of pearly white mass of desquamated epithelial cells in the deep meatus is called keratosis obturans.By its pressure effects causes absorption of bone leading to widening of meatus so much sothat facial nerve may be exposed and paralysed.Commonly seen between 5-20 years of ageMay affect one or both earsEtiology:Sometimes associated with bronchiectasis and chronic sinusitisNormally epithelium from surface of tympanic membrane migrates onto the posterior meatal wall. Failure of this migration or obstruction to the migration caused by wax may lead to accumulation of epithelial plug in the deep meatus.Clinical Features:Pain in the ear, hearing loss, tinnitus, sometimes ear dischargeExamination:Ear canal may be full of pearly white mass of keratin material disposed in several layers.Removal of this mass may show widening of bony meatus with ulceration and granuloma formation.Treatment:Keratotic mass is removed either by syringing or instrumentation.