History

Fact Explanation
Otalgia. Due to acute inflammation of the ear canal skin and subdermis [1].
Hearing loss. It is a conductive hearing loss due to the otorrhoea and debris within the canal [2].
Ear fullness and itching. Due to the oedematous skin of the external auditory canal which obstructs the glands [3].
Tinnitus. It occurs as a result of the inflammatory process extending to the inner ear [4].
Severe, deep pain. Due to the inflammation extending to the bony-cartilaginous junction [3].
Ear discharge. It is associated with the eczematous skin reaction which occurs in the external auditory canal [5].
History of exposure to activities in water (eg: swimming) Cerumen creates a slightly acidic pH that inhibits infection. This can be altered by water exposure. Additionally, several causative organisms are present in swimming pools and similar places [1].
Regular cleaning of the ear canal. It removes cerumen, which is an important barrier to moisture and infection [1].
References
  1. ROSENFELD R, BROWN L, CANNON C, DOLOR R, GANIATS T, HANNLEY M, KOKEMUELLER P, MARCY S, ROLAND P, SHIFFMAN R. Clinical practice guideline: Acute otitis externa. Otolaryngology - Head and Neck Surgery [online] 2006 April, 134(4):S4-S23 [viewed 04 July 2014] Available from: doi:10.1016/j.otohns.2006.02.014
  2. VAN BALEN F. A M. Clinical efficacy of three common treatments in acute otitis externa in primary care: randomised controlled trial. BMJ [online] 2003 November, 327(7425):1201-1205 [viewed 04 July 2014] Available from: doi:10.1136/bmj.327.7425.1201
  3. HUGHES E., LEE J. H.. Otitis Externa. Pediatrics in Review [online] 2001 June, 22(6):191-197 [viewed 04 July 2014] Available from: doi:10.1542/pir.22-6-191
  4. NONDAHL DM, CRUICKSHANKS KJ, HUANG GH, KLEIN BE, KLEIN R, NIETO FJ, TWEED TS. Tinnitus and its Risk Factors in the Beaver Dam Offspring Study Int J Audiol [online] 2011 May, 50(5):313-320 [viewed 04 July 2014] Available from: doi:10.3109/14992027.2010.551220
  5. LUDMAN H. Discharge from the ear: otitis externa and acute otitis media. Br Med J [online] 1980 Dec 13, 281(6255):1616-1617 [viewed 05 July 2014] Available from: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1715058

Examination

Fact Explanation
Tenderness on palpation of the tragus or applying traction to the pinna. Due to traction on the external auditory canal, the skin of which has undergone acute inflammatory changes [1].
Erythema, edema, and narrowing of the external auditory canal with an associated purulent or serous discharge on otoscopic examination. As a result of cellulitis of the ear canal skin and subdermis [2], with an associated eczematous skin reaction [3].
Conductive hearing loss during tuning fork examination. It is due to the otorrhoea and debris within the canal [4].
Inflamed tympanic membrane on otoscopic examination. Due to acute inflammation involving the tympanic membrane [2].
Preauricular, parotid and cervical lymphadenopathy. The external auditory canal is drained by these lymph nodes. Therefore infection spreading via lymphatics can cause lymphadenopathy in these groups [5].
Tenderness in the region of the ipsilateral parotid gland and temporomandibular joint. Infection can spread through the fissures of santorini to these regions [1].
Nerve palsies involving VII, IX, X, XI and XII cranial nerves. Medial spread of infection to the infratemporal fossa leads to involvement of cranial bones and possibly to osteomyelitis of the base of the skull from which these nerves leave the cranium [1].
Granulation tissue or exposed bone seen on the floor of the canal at the bony–cartilaginous junction on otoscopic examination. This occurs in malignant otitis externa caused most often by Pseudomonas aeruginosa which produces lytic enzymes, including endotoxin, collagenase, and elastase, causing a necrotizing vasculitis and endarteritis that enable invasion of surrounding tissue. This is later replaced by granulation tissue [6].
References
  1. HUGHES E., LEE J. H.. Otitis Externa. Pediatrics in Review [online] 2001 June, 22(6):191-197 [viewed 04 July 2014] Available from: doi:10.1542/pir.22-6-191
  2. ROSENFELD R, BROWN L, CANNON C, DOLOR R, GANIATS T, HANNLEY M, KOKEMUELLER P, MARCY S, ROLAND P, SHIFFMAN R. Clinical practice guideline: Acute otitis externa. Otolaryngology - Head and Neck Surgery [online] 2006 April, 134(4):S4-S23 [viewed 04 July 2014] Available from: doi:10.1016/j.otohns.2006.02.014
  3. LUDMAN H. Discharge from the ear: otitis externa and acute otitis media. Br Med J [online] 1980 Dec 13, 281(6255):1616-1617 [viewed 05 July 2014] Available from: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1715058
  4. VAN BALEN F. A M. Clinical efficacy of three common treatments in acute otitis externa in primary care: randomised controlled trial. BMJ [online] 2003 November, 327(7425):1201-1205 [viewed 04 July 2014] Available from: doi:10.1136/bmj.327.7425.1201
  5. FRIEDMANN A. M.. Evaluation and Management of Lymphadenopathy in Children. Pediatrics in Review [online] 2008 February, 29(2):53-60 [viewed 05 July 2014] Available from: doi:10.1542/pir.29-2-53
  6. CARFRAE MATTHEW J., KESSER BRADLEY W.. Malignant Otitis Externa. Otolaryngologic Clinics of North America [online] 2008 June, 41(3):537-549 [viewed 06 July 2014] Available from: doi:10.1016/j.otc.2008.01.004

Differential Diagnoses

Fact Explanation
Otitis media. It also presents with otalgia and conductive hearing loss but a tympanic membrane that is draining pus or red and bulging on otoscopic examination in a sick patient is indicative of otitis media [1].
Furunculosis. Otalgia and otorrhoea is present but the tenderness in localized [2].
Ramsay Hunt Syndrome. It also presents with severe otalgia, but vesicles on the external ear canal and posterior surface of the auricle, facial paralysis or paresis, loss of taste on the anterior two-thirds of the tongue are other features known to be present [2].
References
  1. FROOM J, CULPEPPER L, GROB P, BARTELDS A, BOWERS P, BRIDGES-WEBB C, GRAVA-GUBINS I, GREEN L, LION J, SOMAINI B. Diagnosis and antibiotic treatment of acute otitis media: report from International Primary Care Network. BMJ [online] 1990 Mar 3, 300(6724):582-586 [viewed 05 July 2014] Available from: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1662354
  2. ROSENFELD R, BROWN L, CANNON C, DOLOR R, GANIATS T, HANNLEY M, KOKEMUELLER P, MARCY S, ROLAND P, SHIFFMAN R. Clinical practice guideline: Acute otitis externa. Otolaryngology - Head and Neck Surgery [online] 2006 April, 134(4):S4-S23 [viewed 04 July 2014] Available from: doi:10.1016/j.otohns.2006.02.014

Investigations - for Diagnosis

Fact Explanation
History and examination is sufficient to come to a diagnosis. Certain hallmark signs such as tenderness of the tragus, pinna, or both, that is often intense and disproportionate to what might be expected based on visual inspection would easily point towards a diagnosis [1].
Gram stain and culture of discharge. Some researchers have demonstrated the polymicrobial nature of otits externa in one third of patients and the role of anaerobic bacteria in one quarter, emphasizing the need to obtain both anaerobic and aerobic cultures in patients who have otits externa that does not respond to treatment [2].
References
  1. ROSENFELD R, BROWN L, CANNON C, DOLOR R, GANIATS T, HANNLEY M, KOKEMUELLER P, MARCY S, ROLAND P, SHIFFMAN R. Clinical practice guideline: Acute otitis externa. Otolaryngology - Head and Neck Surgery [online] 2006 April, 134(4):S4-S23 [viewed 04 July 2014] Available from: doi:10.1016/j.otohns.2006.02.014
  2. HUGHES E., LEE J. H.. Otitis Externa. Pediatrics in Review [online] 2001 June, 22(6):191-197 [viewed 04 July 2014] Available from: doi:10.1542/pir.22-6-191

Investigations - Screening/Staging

Fact Explanation
Fasting blood glucose levels. Malignant (progressive necrotizing) otitis externa is an aggressive infection that can complicate simple infection predominantly in diabetic patients due to their immunocompromised states so screening for diabetes mellitus in the elderly with infection is useful [1].
High resolution CT scan. Computed tomographgy can help delineate soft tissue inflammation and the extent of infection and bony erosion in necrotizing otitis externa [2].
References
  1. ROSENFELD R, BROWN L, CANNON C, DOLOR R, GANIATS T, HANNLEY M, KOKEMUELLER P, MARCY S, ROLAND P, SHIFFMAN R. Clinical practice guideline: Acute otitis externa. Otolaryngology - Head and Neck Surgery [online] 2006 April, 134(4):S4-S23 [viewed 04 July 2014] Available from: doi:10.1016/j.otohns.2006.02.014
  2. HUGHES E., LEE J. H.. Otitis Externa. Pediatrics in Review [online] 2001 June, 22(6):191-197 [viewed 04 July 2014] Available from: doi:10.1542/pir.22-6-191

Management - General Measures

Fact Explanation
Acetaminophen for analgesia. Dose: 325-650 mg 6-8 hourly. It inhibits COX-3 enzyme in the brain and spinal cord, thereby reducing production of prostaglandin, which is an important element in the pain pathway [1].
Use of earplugs while swimming. Cerumen creates a slightly acidic pH that inhibits infection. This can be altered by water exposure. Additionally, several causative organisms are present in swimming pools and similar places [2].
Avoidance of manipulation of the ear canal. To avoid irritation and maceration of the skin which are known predisposing factors for otitis externa [3].
References
  1. CHANDRASEKHARAN N. V., DAI H., ROOS K. L. T., EVANSON N. K., TOMSIK J., ELTON T. S., SIMMONS D. L.. COX-3, a cyclooxygenase-1 variant inhibited by acetaminophen and other analgesic/antipyretic drugs: Cloning, structure, and expression. Proceedings of the National Academy of Sciences [online] December, 99(21):13926-13931 [viewed 07 July 2014] Available from: doi:10.1073/pnas.162468699
  2. ROSENFELD R, BROWN L, CANNON C, DOLOR R, GANIATS T, HANNLEY M, KOKEMUELLER P, MARCY S, ROLAND P, SHIFFMAN R. Clinical practice guideline: Acute otitis externa. Otolaryngology - Head and Neck Surgery [online] 2006 April, 134(4):S4-S23 [viewed 04 July 2014] Available from: doi:10.1016/j.otohns.2006.02.014
  3. HUGHES E., LEE J. H.. Otitis Externa. Pediatrics in Review [online] 2001 June, 22(6):191-197 [viewed 04 July 2014] Available from: doi:10.1542/pir.22-6-191

Management - Specific Treatments

Fact Explanation
Removal of debris from the ear canal - Gentle cleaning with a soft plastic curette or a small Frazier suction tip under direct vision. To ensure adequate delivery of the topical medication [1].
Hydrocortisone and acetic acid otic solution. Dose: 3-5 drops to the affected ear 4-6 times per day. Steroids reduce inflammation while acidic solutions lower the pH of the canal, thereby inhibiting growth of organisms which prefer an alkaline environment [2].
Ofloxacin otic preparation. Dose: 10 drops 4 times a day. Studies prove an increase in causative organism susceptibility and bacteriological cure with the use of quinolones when compared to non-quinolone antibiotics [1].
Oral antibiotics (eg: ciprofloxacin) When there is spread of infection beyond the external auditory canal such as cellulitis of surrounding structures or lymphadenitis [2].
IV antibiotics. It is used in necrotizing otitis externa which is a severe variant that usually is caused by P. aeruginosa and is associated with systemic invasion [2].
Placement of an ear wick. It is used if the canal walls are too swollen to allow penetration of the drug along its length [3].
References
  1. ROSENFELD R, BROWN L, CANNON C, DOLOR R, GANIATS T, HANNLEY M, KOKEMUELLER P, MARCY S, ROLAND P, SHIFFMAN R. Clinical practice guideline: Acute otitis externa. Otolaryngology - Head and Neck Surgery [online] 2006 April, 134(4):S4-S23 [viewed 04 July 2014] Available from: doi:10.1016/j.otohns.2006.02.014
  2. HUGHES E., LEE J. H.. Otitis Externa. Pediatrics in Review [online] 2001 June, 22(6):191-197 [viewed 04 July 2014] Available from: doi:10.1542/pir.22-6-191
  3. VAN BALEN F. A M. Clinical efficacy of three common treatments in acute otitis externa in primary care: randomised controlled trial. BMJ [online] 2003 November, 327(7425):1201-1205 [viewed 06 July 2014] Available from: doi:10.1136/bmj.327.7425.1201