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otitis externa

Etiology: 1) infection a) bacterial (generally acute) - Staphylococcus - Streptococcus - Pseudomonas (necrotizing otitis externa) - older diabetic patients - ear irrigation may be predisposing factor - Proteus - Mycoplasma (Bullous myringitis) - Actinomyces (chronic) b) fungal (chronic) - Candida - Aspergillus - Mucor 2) local trauma or environmental exposure - cotton-tipped swab - hairpin - swimmer's ear - may be secondary infection 3) cerumen impaction - seborrheic external otitis 4) eczematoid external otitis - allergic hypersensitivity - contact dermatitis - atopic dermatitis - psoriasis 5) foreign body Pathology: 1) cellulitis of the external auditory canal [9] 2) localized infection as in a pustule or furuncle which arises in hair follicles in the outer portion of the ear canal 3) local trauma or environmental exposure leading to diffuse inflammation (swimmer's ear) 4) chronic irritation from a perforated otitis media with suppuration 5) chronic eczema 6) conductive hearing loss History: 1) swimming 2) trauma 3) upper respiratory tract infection Clinical manifestations: 1) earache (otalgia) 2) itching (pruritus) 3) conductive hearing loss - Weber test lateralizes to the affected ear 4) vertigo 5) tympanic membrane appearance is normal 6) erythema of auricle: cellulitis; furuncle 7) pain on movement of auricle or with mastication 8) ear discharge a) white, cheezy or mucous-like material may prevent visualization of the tympanic membrane b) may be green or yellow c) may be copious & foul-smelling to minimal with malignant otitis d) black discharge suggests fungal origin 9) periauricular & cervical lymphadenopathy 10) seborrheic or eczematoid otitis externa a) flaking, crusting or weeping of skin Laboratory: 1) KOH preparation of discharge if fungal infection is suspected 2) cultures of discharge only if patient is immunocompromised or does not respond to standard therapy 3) if necrotizing otitis externa is suspected a) erythrocyte sedimentation rate (ESR) b) complete blood count (CBC) Radiology: - computed tomography (CT) if suspected necrotizing otitis externa Differential diagnosis: 1) eustachian tube dysfunction - may be associated with seasonal allergies 2) cutaneous neoplasm (persistent inflammation) 3) malignant otitis externa (necrotizing otitis externa) a) associated with diabetes mellitus or immunosuppression b) systemically ill c) otalgia out of proportion to visible findings [9] c) evidence of infection spread beyond the external auditory canal - facial nerve palsy [9] 4) recurrent furuncles suggests diabetes mellitus 5) Ramsay-Hunt syndrome caused by Herpes zoster a) sensorineural hearing loss b) facial nerve paralysis c) vesicular lesions on & in the external auditory canal 6) acute myringitis due to Mycoplasma or viral infection 7) see earache Management: 1) factors that modify management [7] a) tympanostomy tube b) perforated tympanic membrane - non-ototoxic topical preparation [7] 2) ear hygiene - clear as much debris from the external auditory canal as possible [2] 3) cerumen impaction a) wax softeners 1] carbamide peroxide (Debrox) 2-3 drops BID 2] Colace 10 mg/mL 1-2 drops BID b) pulsating irrigation device (contraindicated if infection suspected) 4) seborrheic or eczematoid external otitis a) treat underlying seborrhea with selenium sulfide shampoo weekly b) hydrocortisone topical cream/lotion to auricle c) add antibiotic if secondary infection is suspected 5) topical agents (infection, inflammation) a) Auralgan (benzocaine & antipyrene) - fill ear as needed for pain b) steroid/antibiotic topical, 4 drops TID/QID 1] ciprofloxacin/dexamethasone (Ciprodex) 4 drops BID for 5 days 2] ciprofloxacin/hydrocortisone (Cipro-HC) 5 drops BID for 5 days 3] Corticosporin otic (polymyxin B, neomycin, hydrocortisone) 4] Coly-Mycin S (neomycin, colistin sulfate, hydrocortisone, thonzonium bromide) 5] treatment of choice [3] c) gentamicin or tobramycin ophthalmic may be used [4] d) Vosol or Domeboro otic (acetic acid, 2%) 3-5 drops BID for mild otitis externa [2] e) acetic acid + triamcinolone better than acetic acidalone [3] f) introducing cotton wick into the ear canal with forceps may facilitate delivery of antibiotic drops g) for otitis externa in patients with perforated eardrum, use Ciprodex (ciprofloxacin/dexamethasone) or ofloxacin otic; these are sterile, Cipro HC is not [5] 6) systemic antibacterial agents a) indicated for malignant otitis externa b) amoxicillin (Amoxil) 250-500 mg TID 30-50 mg/kg/day divided TID for child c) erythromycin 500 mg BID 30-50 mg/kg/day divided TID/QID for child d) Augmentin 1 tab TID e) pediazole f) systemic antipseudomonal cephalosporin &/or fluoroquinolone for for necrotizing otitis externa in diabetics - IV ceftazidime, IV ciprofloxaxin g) ref [2] recomments hospitalization & IV antibiotics 7) systemic glucorticoid & antiviral agent for Ramsay-Hunt syndrome 8) patient education a) avoid water sports until resolution b) peroxide or alcohol drops after swimming & showering c) ear plugs worn during swimming

Related

earache; otalgia Ramsay-Hunt syndrome

Specific

eczematoid otitis externa malignant otitis externa otomycosis; fungal otitis externa swimmer's ear (tropical ear)

General

external ear disease otitis

References

  1. Saunders Manual of Medical Practice, Rakel (ed), WB Saunders, Philadelphia, 1996, pg 40-42, 82-83
  2. Medical Knowledge Self Assessment Program (MKSAP) 11, 14, 15, 16. American College of Physicians, Philadelphia 1998, 2006, 2009, 2012
  3. Journal Watch 24(2):17, 2004 van Balen FAM et al, BMJ 327:1201, 2003 http://bmj.bmjjournals.com/cgi/content/full/327/7425/1201 PMID: 14630756
  4. Prescriber's Letter 13(10): 2006 Alternative or 'Off-label' Routes of Drug Administration Detail-Document#: 221012 (subscription needed) http://www.prescribersletter.com
  5. Prescriber's Letter 16(8): 2009 COMMENTARY: Drug Treatments for Swimmer's Ear: An Update GUIDELINES: Acute Otits Externa Detail-Document#: 250821 (subscription needed) http://www.prescribersletter.com
  6. Osguthorpe JD, Nielsen DR. Otitis externa: Review and clinical update. Am Fam Physician. 2006 Nov 1;74(9):1510-6. PMID: 17111889
  7. Rosenfeld RM et al Clinical Practice Guideline. Acute Otitis Externa Executive Summary Otolaryngol Head Neck Surg February 2014 150(2):161-168 PMID: 24492208 http://oto.sagepub.com/content/150/2/161.full
  8. Prescriber's Letter 21(6): 2014 Treatment of Acute Otitis Externa Detail-Document#: 300607 (subscription needed) http://www.prescribersletter.com
  9. NEJM Knowledge+ Otolaryngology - Rosenfeld RM, Schwartz SR, Cannon CR et al Clinical practice guideline: acute otitis externa. Otolaryngol Head Neck Surg. 2014 Feb;150(1 Suppl):S1-S24. PMID: 24491310 Review
  10. Hajioff D, MacKeith S. Otitis externa. BMJ Clin Evid. 2015;2015. PMID: 26074134