1. The External Ear

2. General Compartments
External
Middle
Inner

3. External Ear Consists of:
Auricle / Pinna: yellow elastic cartilage except the lobule.
External Auditory Canal:
24mm in length
S – shaped (not straight)
2 parts:
Cartilaginous Part: outer 1/3, skin contains ceruminous and pilosebaceous glands which secret wax, and hair follicles.
Bony Part: inner 2/3, skin is thin and continuous with outer layer of tympanic membrane.

4. External Ear (continued)
Tympanic Membrane:
Oblique, oval
9-10 mm tall, 8-9 mm wide, 0.1 mm thick.
Layers: 3 layers
Outer epithelial layer: continuous with the skin lining the ear canal
Inner mucosal layer: continuous with the mucosa of the middle ear.
Middle fibrous layer: more well- formed and organized in pars tensa.
2 parts:
Pars Tensa: most of TM, periphery is thickened to form the annulus.
Pars Flaccida: above the lateral process of malleus

5. Cerumen
consists of desquamated epithelium mixed with the sebum produced from sebaceous glands and the watery secretions of modified apocrine sweat glands (apopilo- sebaceous unit)
acidic: bacteriostatic + fungostatic
contains lysozymes which are bactericidal

6. Nerve Supply
Anterior part: Auriculotemporal branch of mandibular branch of trigeminal (V)
Posterior and central part: auricular branch of Vagus Nerve (X), Facial nerve (VII)
Posterior and inferior part: cervical C2, C3
Understanding innervation is important to understand referred ear pain

7. External ear Embryology:
Condensation of the mesoderm of the 1st and 2nd pharyngeal/brachial arches occurs to give rise to 6 hillocks of His
20th week gestation: It has reached adult shape
9 years: reach adult size (this is the age of performing plastic surgery)

8. Congenintal anomalies of the Pinna
Preauricular tag
Remnant of one of the hillocks.
Uncertain risk factor for hearing loss.
Preauricular sinus
results from improper fusion of the 1st & 2nd brachial arches
May be associated with branchio-oto-renal syndrome
Surgery is only indicated when it is complicated by recurrent infection or abscesses
Microtia: underdeveloped ear pinna
Bat ears: protruding ears, loss of antihelix

9. Preauricular Tag

10. Trauma to the Auricle Haematoma of the Auricle:
Collection of blood between the cartilage and its perichondrium.
A result of blunt trauma, e.g. boxers, wrestlers.
Extravasated blood may clot and organize resulting in “Cauliflower Ear” or “Boxers Ear”
Treatment: either repeated aspiration under aseptic precautions with pressure dressing or incision and drainage with pressure dressing and prophylactic antibiotics.
Haematoma
Cauliflower ear

11. Infections of the auricle
Erysipelas:
infection of the overlying skin
Caused by group A beta hemolytic strep.
Rapid treatment with oral or IV antibiotic
cellulitis (infection of the soft tissue)
Cellulitis of the ear typically results from a spreading otitis externa or a penetrating injury.
It is distinguished from perichondritis by the lack of induration
Rapid treatment with Anti-staph oral or IV antibiotic
Perichondiritis to chondritis :
represent infections of the auricular perichondrium or cartilage
Secondary to lacerations, haematoma, surgical incisions or piercings. Or as an extension from diffuse otitis externa.
infection involving the cartilage itself of the auricle & external auditory canal.
The lobule, which contains no cartilage, is spared
Most common cause is Pseudomonas aeruginosa and mixed flora.
Treament: systemic and local antibiotics. In case of abscess formation, it must be drained promptly and treated with systemic and local antobiotics.

12. Relapsing Polychondritis
Auto-immune disease
Other cartilages may be involved like septal, laryngeal, tracheal and costal cartilages.
presentation:
acute phase: fever
sudden sever painful uniform swelling and erythema of the auricle
Chondritis rapidly develops and resolves in days
Spares: external auditory canal, lobule

13. Inflammations of Ear Canal

14. External auditory canal infections
Furunculosis
Furuncle is a localized abscess of the apopilo-sebaceous unit
Most common organism: Staph aureus.
Confined to the outer 1/3 of the ear canal.
Symptoms: severe pain and tenderness.
Treatment:
Analgesia
Anti-staphylococcal oral and topical antibiotics should be administered.
A fluctuant lesion should be incised and drained under local anesthetic.

15. Otitis externa
Diffuse swelling of the meatal skin which may spread to the pinna and epidermal layer of the tympanic membrane.
Approximately 80% of cases occur in the summer, particularly in warm, humid environments.
Other predisposing factors include anatomic obstructions of the ear canal (e.g., stenosis, impacted cerumen), hearing aid or ear plug use, self-induced trauma (e.g., by cotton swabs), and swimming, secondary to chronic middle ear discharge.
Common pathogens: Staph aureus, Pseudomonas pyocyaneus, Bacillis proteus, E coli but more often the infection is mixed.
Symptoms: hot, burning sensation in the ear, pain, discharge, inflamed swollen meatal skin.
Treatment :
Frequent aural toileting
Local and systemic antibiotics
Medicated ear wicks/packs
Analgesics
Avoid water contact

16. Fungal otitis externa (otomycosis)
Aspergillus accounts for % of cases with Candida being responsible for the remaining %.
In hot, humid climates.
Secondary fungal growth is also seen in patients using topical antibiotics for treatment of otitis externa or middle ear suppuration.
Presentation: intense itching, discomfort or pain in the ear, watery discharge with a musty odour and ear blockage. The fungal mass may appear white, brown or black and has been likened to a wet piece of filter paper.
Treatment :
Frequent aural toileting
Local antifungal
Avoid water contact
Aspergillus
Candida

17. Malignant (Necrotizing) otitis externa
Malignant Otitis Externa: otitis externa + osteomyelitis of the tympanic plate of the temporal bone which may extend to involve skull base
Clinical Presentation:
Persistent Otalgia more than 1 month
Persistent Otorrhea with granulation tissue
Persistent Otorrhea in the immunocompromised patients (Diabetics with microangiopathy and cellular immune dysfunction), HIV.
Deep-seated aural pain (pain out of proportion to examination findings).
Facial nerve palsy and multiple lower cranial nerves palsy.
Most cases are caused by P. aeruginosa
Diagnostic:
CT scan with IV contrast
MRI
Gallium-67 and Technetium-99m bone scanning

18. Malignant (Necrotizing) otitis externa
Treatment:
Regular aural toilet
Blood sugar control
Correct immunodeficiency if possible
Pain killer
Infectious disease consult
IV antibiotic for 6-8 weeks, with anti-pseudomonal coverage (gentamicin+ticarcillin or ceftazidime+aminoglycoside or quinolones like ciprofloxacin)
Prognosis:
Mortality is 5-20%

19. Herpes Zoster Oticus prodrome of otalgia, which may be severe.
A vesicular eruption is seen in the canal and concha.
Ultimately, these vesicles rupture and form crusts.
Etiology:
After primary infection (chickenpox), varicella-zoster virus is harbored in a latent state in sensory ganglia, and reactivates with infection spreading along dermatomes.
Harbored in the facial nerve VII and the vestibular ganglia of VIII
A subgroup of patients manifest Ramsay Hunt syndrome: SNHL, tinnitus or vertigo or both, Palsy: lower motor neuron palsy of the ipsilateral facial nerve
2nd commonest cause of lower facial nerve palsy after bell's palsy (9%)
Prognosis for facial nerve recovery worse than Bell’s palsy (only 60% regain normal function, where as up 90% regain normal function in bell’s palsy).
Symptoms:
Auricular pain: the 1st symptom to appear
Vesicular Rash: location: concha, EAC, mucosa of the palate, anterior 2/3 of the tongue
Treatment:
acyclovir or valacyclovir
High-dose steroids
Corneal protection