Otitis Externa
otitisOuter ear infection or otitis externa is frequently seen in Primary Care. This review of otitis externa on A4Medicine here is to make the reader aware of other conditions which can present similarly- Differential diagnosis and particular focus area on malignant or the necrotizing type ( osteomyelitis of the temporal bone ). Complexity in interpreting ear swab results is discussed. Treatment options are mentioned with a focus on topical treatment.
Inflammatory condition of the ear canal with or without infection Seen in all age group Common presenting complain in UK primary care Peak incidence in one study was in children 7-12 yrs Around 10 % of people will experience at-least one episode in their lifetime Increase in episodes end of summer
It can be difficult to distinguish OE from otitis media with discharge- if canal has discharge and swelling and TM cannot be seen Topical antibiotics are also Rx of choice for AOM with discharge and acute typmanostomy tube otorrhoea
Predisposing factors –Warm humid climate Moisture – macerates the skin of ear canal pH and damages the protective layer of cerumen ○ swimming ○ perspiration ○ high humidity Trauma – breach in integrity of canal ○ cotton buds ○ fingernails ○ hearing aids ○ ear plugs ○ paper clips ○ match sticks ○ mechanical wax removal Anatomical – narrow hairy ear canal Inadequate wax- loss of protective layer or Wax build up Immunocompromised Chronic dermatological conditions as atopic dermatitis Allergic , atopic or irritant dermatitis affecting the ear canal
Causes-Bacterial ( up to 90 % of cases ) ○ pseudomonas ○ staph aureus Fungal infections ○ over treatment with antibiotics ○ de novo ○ Aspergillus in 90 % cases ○ candida also isolated Seborrhoeic dermatitis Contact dermatitis can be ○ Allergic or Irritant Allergic can present as sudden onset , erythematous , itchy , oedeomatous and exudative lesions ○ earrings ○ hearing aid Trauma
Presentation-Otalgia Itch Fullness Tinnitus Pain worse when outer ear touched or moved gently or otoscope inserted Ear canal pain when chewing Tender regional lymphadenopathy Jaw pain Hearing loss if the canal very swollen Ear canal or external ear can be red swollen or eczematous Canal edematous and erythematous and may be associated with surrounding cellulitis Discharge may be present Eardrum may be obscured as the ear canal is narrowed or filled with debris Conductive hearing loss
Differential diagnosis –Wax impaction Acute otitis media Otitis media with perforation or ventilation tube present Mastoiditis Foreign body Ear canal trauma Cholesteatoma Malignant or Necrotizing OE Furuncle Ear canal carcinoma Cranial N palsy Wisdom tooth eruption Intracranial abscess Ramsay Hunt syndrome Skull base osteomyelitis Periauricular cyst and fistula Atopic dermatatis Barotrauma Referred pain
Malignant or Necrotizing-Osteomyelitis of the Temporal bone Severe headache , fever over 39° or over Intense otalgia that worsens at night Profound hearing loss Temperol mandibular jt pain Trismus Vertigo Facial N palsy ( drooping face side of lesion ) Exposed bone in ear canal Granulation tissue on floor of ear canal It is an invasive infection of cartilage and bone of the canal and external ear risk factors-Diabetes – present in most cases with malignant otitis Compromised immunity eg ○ HIV/ AIDS ○ chemotherapy ○ CKD Radiotherapy to head or neck Aural irrigation with tap water ( in people with co-existant other risk factors )
Most cases in UK treated in Primary care Only 3 % are referred to secondary care ( Rowlands 2001 ) Mainstay of treatment is ○ pain relief ○ topical medications to control infection and oedema ○ avoidance of contributing factors Patients referred to secondary care usually due to
Common-Antibacterial ear drops used in the UK Aminoglycoside Neomycin Gentamicin Potentially ototoxic if ear drum perforated Neomycin associated with a 15 % incidence of contact dermatitis Fluoroquinolone Ciprofolxacin Ofloxacin Non-ototoxic Twice daily Can be used in people with perforated ear drum Not licensed for use in UK but widely used and deemed acceptable by ENT UK ( Phillips 2007 ) Topical antibiotics 1st line for diffuse , uncomplicated acute OE No evidence to suggest which product is more effective Prescribe with or without topical steroid for 7-10 days Prescribe a non-ototoxic preparation when the patient has a known or suspected perforation of the TM including a tympanostomy tube Clinical response should be evident within 48-72 hrs but complete recovery can take upto 2 weeks Advice on correct technique of use
Astringent / acidic preparations ○ eg Aluminium acetate 8 % and 13 % ( special order ) ○ Acetic acid 2 % spray ( Earcalm® ) can be used in mild cases Guideline from PHE recommends 2 % acetic spray for 7 days as first line empirical treatment BMJ 2014 in OE Corticosteroids ○ prednisolone sodium phosphate 0.5 % ○ betamethasone sodium phosphate 0.1 % Antibiotics ○ mentioned above and also Chloramphenicol 5 % drops Antifungal – Clotrimazole 1 % solution Combined preparations Cilodex® – Dexamethasone 0.1 % and ciprofloxacin 0.3 % Neomycin various combinations including the popular Otomize which is Dexamethasone + Glacial acetic acid + Neomycin sulfate Gentisone HC -gentamicin 0.3 % and 1 % HC Sofradex® Dex 0.05% + framycetin 0.5% + gramicidin Corticosteroid and antibiotic/antifungal- Flumetasone pivalate + clioquinol
Follow up-Localized OE f/u is normally not required- usually mild and self limiting Consider f/u if oral antibiotics prescribed Immunocompromised Abstain from water sports 7-10 days after an acute attack Most common pathogens are Pseudomonas aeruginosa & Staphlococcus aureus
Systemic antibiotics-Oral antibiotics are rarely needed. Consider seeking specialist advice if an oral antibiotics is thought to be required cellulitis extending beyond the ear canal ear canal occluded by swelling and debris and wick cannot be inserted people with diabetes or compromised immunity and severe infection or high risk of severe infection Use flucloxacillin or clarithromycin if allergic to penicillin for 7 days Consider appropriate f/u
LINKS AND RESOURCES
PATIENT RESOURCES
A useful and concise summary from BUPA https://www.bupa.co.uk/health-information/ears-hearing/outer-ear-infection
From Patient UK https://patient.info/ears-nose-throat-mouth/earache-ear-pain/ear-infection-otitis-externa
A comprehensive patient information section from NHS Inform Scot https://www.nhsinform.scot/illnesses-and-conditions/ears-nose-and-throat/otitis-externa#about-otitis-externa
An excellent review from HSE https://www.hse.ie/eng/health/az/e/ear-infection,-outer/complications-of-otitis-externa.html
FOR HEALTHCARE PROFESSIONALS
Americal Academy of Otolaryngology Head and Neck Surgery – Clinical Practice Guideline : Acute Otitis Externa https://journals.sagepub.com/doi/pdf/10.1177/0194599813517083
same from https://www.entnet.org/content/clinical-practice-guideline-acute-otitis-externa
BNF treatment summary https://bnf.nice.org.uk/treatment-summary/ear.html
BMJ Best Practice Otitis Externa acute https://bestpractice.bmj.com/topics/en-gb/40/guidelines
Acute Otitis Externa – Practice Point Canadian Paediatric Society https://www.cps.ca/en/documents/position/acute-otitis-externa
An excellent open-access review article from Primary Care: Clinics in Office Practice https://www.primarycare.theclinics.com/article/S0095-4543(13)00097-3/fulltext
References
- Otitis externa 10 minute consultation BMJ ;344:e3623
- Intervention for acute otitis externa Vivek Kaushik et al Cochrane Database of Systemic Reviews January 2010
- Acute otitis externa Canadian Paediatric Society Feb 2013
- Otitis Externa and Painful ,Discharging Ears Patient UK
- Clinical Reference Necrotising ( malignant ) otitis externa in the UK : a growing problem. Review of five cases and analysis if national Hospital Episode trends Chawdhary G et al J Larnygol Otol. 2015 Jun ;129 (6) :600-3 ( Abstract )
- CKS NHS Otitis externa December 2016
- UK Standards for Microbiology Investigations : Investigations of Ear Infections and Associated Specimens Bacteriology B1 Issue no 9 June 2016
- Clinical practice guideline : acute otitis externa Rosenfeld RM et al Otolaryngol head and Neck Surg . 2014 Feb ; 150 ( 1 Suppl ) :S1-S24
- Otitis externa Medscape Ariel A Waitzman et al Updated May 2017
- Ordering and interpreting ear swabs in otitis externa BMJ 2014 ; 349 :g5259
