Infections of the External Ear : Infections of the External Ear Michael Underbrink, MD
Jeffrey Vrabec, MD
March 21, 2001
Anatomy and Physiology : Anatomy and Physiology Consists of the auricle and EAM
Skin-lined apparatus
Approximately 2.5 cm in length
Ends at tympanic membrane
Anatomy and Physiology : Anatomy and Physiology Auricle is mostly skin-lined cartilage
External auditory meatus
Cartilage: ~40%
Bony: ~60%
S-shaped
Narrowest portion at bony-cartilage junction
Anatomy and Physiology : Anatomy and Physiology
Anatomy and Physiology : Anatomy and Physiology EAC is related to various contiguous structures
Tympanic membrane
Mastoid
Glenoid fossa
Cranial fossa
Infratemporal fossa
Anatomy and Physiology : Anatomy and Physiology Innervation: cranial nerves V, VII, IX, X, and greater auricular nerve
Arterial supply: superficial temporal, posterior and deep auricular branches
Venous drainage: superficial temporal and posterior auricular veins
Lymphatics
Anatomy and Physiology : Anatomy and Physiology Squamous epithelium
Bony skin – 0.2mm
Cartilage skin
0.5 to 1.0 mm
Apopilosebaceous unit
Otitis Externa : Otitis Externa Bacterial infection of external auditory canal
Categorized by time course
Acute
Subacute
Chronic
Acute Otitis Externa (AOE) : Acute Otitis Externa (AOE) “swimmer’s ear”
Preinflammatory stage
Acute inflammatory stage
Mild
Moderate
Severe
AOE: Preinflammatory Stage : AOE: Preinflammatory Stage Edema of stratum corneum and plugging of apopilosebaceous unit
Symptoms: pruritus and sense of fullness
Signs: mild edema
Starts the itch/scratch cycle
AOE: Mild to Moderate Stage : AOE: Mild to Moderate Stage Progressive infection
Symptoms
Pain
Increased pruritus
Signs
Erythema
Increasing edema
Canal debris, discharge
AOE: Severe Stage : AOE: Severe Stage Severe pain, worse with ear movement
Signs
Lumen obliteration
Purulent otorrhea
Involvement of periauricular soft tissue
AOE: Treatment : AOE: Treatment Most common pathogens: P. aeruginosa and S. aureus
Four principles
Frequent canal cleaning
Topical antibiotics
Pain control
Instructions for prevention
Chronic Otitis Externa (COE) : Chronic Otitis Externa (COE) Chronic inflammatory process
Persistent symptoms (> 2 months)
Bacterial, fungal, dermatological etiologies
COE: Symptoms : COE: Symptoms Unrelenting pruritus
Mild discomfort
Dryness of canal skin
COE: Signs : COE: Signs Asteatosis
Dry, flaky skin
Hypertrophied skin
Mucopurulent otorrhea (occasional)
COE: Treatment : COE: Treatment Similar to that of AOE
Topical antibiotics, frequent cleanings
Topical Steroids
Surgical intervention
Failure of medical treatment
Goal is to enlarge and resurface the EAC
Furunculosis : Furunculosis Acute localized infection
Lateral 1/3 of posterosuperior canal
Obstructed apopilosebaceous unit
Pathogen: S. aureus
Furunculosis: Symptoms : Furunculosis: Symptoms Localized pain
Pruritus
Hearing loss (if lesion occludes canal)
Furunculosis: Signs : Furunculosis: Signs Edema
Erythema
Tenderness
Occasional fluctuance
Furunculosis: Treatment : Furunculosis: Treatment Local heat
Analgesics
Oral anti-staphylococcal antibiotics
Incision and drainage reserved for localized abscess
IV antibiotics for soft tissue extension
Otomycosis : Otomycosis Fungal infection of EAC skin
Primary or secondary
Most common organisms: Aspergillus and Candida
Otomycosis: Symptoms : Otomycosis: Symptoms Often indistinguishable from bacterial OE
Pruritus deep within the ear
Dull pain
Hearing loss (obstructive)
Tinnitus
Otomycosis: Signs : Otomycosis: Signs Canal erythema
Mild edema
White, gray or black fungal debris
Otomycosis : Otomycosis
Otomycosis: Treatment : Otomycosis: Treatment Thorough cleaning and drying of canal
Topical antifungals
Granular Myringitis (GM) : Granular Myringitis (GM) Localized chronic inflammation of pars tensa with granulation tissue
Toynbee described in 1860
Sequela of primary acute myringitis, previous OE, perforation of TM
Common organisms: Pseudomonas, Proteus
GM: Symptoms : GM: Symptoms Foul smelling discharge from one ear
Often asymptomatic
Slight irritation or fullness
No hearing loss or significant pain
GM: Signs : GM: Signs TM obscured by pus
“peeping” granulations
No TM perforations
GM: Treatment : GM: Treatment Careful and frequent debridement
Topical anti-pseudomonal antibiotics
Occasionally combined with steroids
At least 2 weeks of therapy
May warrant careful destruction of granulation tissue if no response
Bullous Myringitis : Bullous Myringitis Viral infection
Confined to tympanic membrane
Primarily involves younger children
Bullous Myringitis: Symptoms : Bullous Myringitis: Symptoms Sudden onset of severe pain
No fever
No hearing impairment
Bloody otorrhea (significant) if rupture
Bullous Myringitis: Signs : Bullous Myringitis: Signs Inflammation limited to TM & nearby canal
Multiple reddened, inflamed blebs
Hemorrhagic vesicles
Bullous Myringitis: Treatment : Bullous Myringitis: Treatment Self-limiting
Analgesics
Topical antibiotics to prevent secondary infection
Incision of blebs is unnecessary
Necrotizing External Otitis(NEO) : Necrotizing External Otitis(NEO) Potentially lethal infection of EAC and surrounding structures
Typically seen in diabetics and immunocompromised patients
Pseudomonas aeruginosa is the usual culprit
NEO: History : NEO: History Meltzer and Kelemen, 1959
Chandler, 1968 – credited with naming
NEO: Symptoms : NEO: Symptoms Poorly controlled diabetic with h/o OE
Deep-seated aural pain
Chronic otorrhea
Aural fullness
NEO: Signs : NEO: Signs Inflammation and granulation
Purulent secretions
Occluded canal and obscured TM
Cranial nerve involvement
NEO: Imaging : NEO: Imaging Plain films
Computerized tomography – most used
Technetium-99 – reveals osteomyelitis
Gallium scan – useful for evaluating Rx
Magnetic Resonance Imaging
NEO: Diagnosis : NEO: Diagnosis Clinical findings
Laboratory evidence
Imaging
Physician’s suspicion
Cohen and Friedman – criteria from review
NEO: Treatment : NEO: Treatment Intravenous antibiotics for at least 4 weeks – with serial gallium scans monthly
Local canal debridement until healed
Pain control
Use of topical agents controversial
Hyperbaric oxygen experimental
Surgical debridement for refractory cases
NEO: Mortality : NEO: Mortality Death rate essentially unchanged despite newer antibiotics (37% to 23%)
Higher with multiple cranial neuropathies (60%)
Recurrence not uncommon (9% to 27%)
May recur up to 12 months after treatment
Perichondritis/Chondritis : Perichondritis/Chondritis Infection of perichondrium/cartilage
Result of trauma to auricle
May be spontaneous (overt diabetes)
Perichondritis: Symptoms : Perichondritis: Symptoms Pain over auricle and deep in canal
Pruritus
Perichondritis: Signs : Perichondritis: Signs Tender auricle
Induration
Edema
Advanced cases
Crusting & weeping
Involvement of soft tissues
Relapsing Polychondritis : Relapsing Polychondritis Episodic and progressive inflammation of cartilages
Autoimmune etiology?
External ear, larynx, trachea, bronchi, and nose may be involved
Involvement of larynx and trachea causes increasing respiratory obstruction
Relapsing Polychondritis : Relapsing Polychondritis Fever, pain
Swelling, erythema
Anemia, elevated ESR
Treat with oral corticosteroids
Herpes Zoster Oticus : Herpes Zoster Oticus J. Ramsay Hunt described in 1907
Viral infection caused by varicella zoster
Infection along one or more cranial nerve dermatomes (shingles)
Ramsey Hunt syndrome: herpes zoster of the pinna with otalgia and facial paralysis
Herpes Zoster Oticus: Symptoms : Herpes Zoster Oticus: Symptoms Early: burning pain in one ear, headache, malaise and fever
Late (3 to 7 days): vesicles, facial paralysis
Herpes Zoster Oticus: Treatment : Herpes Zoster Oticus: Treatment Corneal protection
Oral steroid taper (10 to 14 days)
Antivirals
Erysipelas : Erysipelas Acute superficial cellulitis
Group A, beta hemolytic streptococci
Skin: bright red; well-demarcated, advancing margin
Rapid treatment with oral or IV antibiotics if insufficient response
Perichondritis: Treatment : Perichondritis: Treatment Mild: debridement, topical & oral antibiotic
Advanced: hospitalization, IV antibiotics
Chronic: surgical intervention with excision of necrotic tissue and skin coverage
Radiation-Induced Otitis Externa : Radiation-Induced Otitis Externa OE occurring after radiotherapy
Often difficult to treat
Limited infection treated like COE
Involvement of bone requires surgical debridement and skin coverage
Conclusions : Conclusions Careful History
Thorough physical exam
Understanding of various disease processes common to this area
Vigilant treatment and patience