1. OTITIS EXTERNA
Dr. Mohammed Shafeeq

2. Definition
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It is a generalised condition of the skin in EAC
characterised by general oedema & erythema
which may be associated with itchy discomfort
with or without ear discharge.

3. External auditory canal - Anatomy
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Bottom of concha to TM
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24mm along posterior border
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Divided into:
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Outer/cartilaginous part
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Inner/bony part
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Outer part – upwards, backwards & medially
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Inner part – downwards,forwards & medially

4. ●
Cartilaginous part:
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8mm, outer 1/3rd
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Fissures of Santorini
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Skin is thick with ceruminous & sebaceous glands
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Hair is confined to this region

5. ●
Bony part:
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16mm, inner 2/3rd
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Tympanic portion of temporal bone
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Skin is thin, with thin layer of sq epithelium
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Devoid of hair/ceruminous glands
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Isthmus
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Anterior recess
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Foramen of Huschke

6. Pathogenesis
Clinical course of otitis externa can be divided
into:
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Pre-inflammatory stage
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Acute inflammatory stage
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Chronic inflammatory stage

7. ●
Pre-inflammatory stage:
protective lipid/acid balance is lost
stratum corneum – oedematous
blocks sebaceous/apocrine glands
-- aural fullness/itching
disruption of epithelial layer
-- invasion of pathogens

8. ●
A/c inflammatory stage:
3 grades – mild / moderate / severe
Pre-inflammatory phase –> acute inflammation
progressive thickening exudate, increasing
oedema
oblitertion of lumen, increasing pain
severe stages – auricular changes & cervical
lymphadenopathy

9. ●
C/c inflammatory stage:
resistant inflammations lasting > 3weeks
thickening of external canal skin
fibrous canal stenosis

10. Pre-disposing factors
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Anatomical - narrow EAC
(hereditary/iatrogenic/exostoses), obstruction of
normal meatus (keratosis obturans/FB/hearing aids)
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Dermatological - eczema,seborrhoeic dermatitis
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Allergic – long term topical medications
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Physiological – humidity, immunocompromised
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Traumatic – skin maceration(swimming), ear
probing, laceration, radiotherapy
Microbiological – active COM, exposure to
P.aeruginosa or fungi

11. Microbiology
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Pseudomonas species -- 50-65%
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Other Gram negative organisms – 25-35%
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Staphylococcus aureus – 15-30%
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Streptococci – 9-15%

12. Classification (etiological basis)
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INFECTIVE group
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Bacterial
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–
–
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Fungal
–
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Otomycosis
Viral
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–
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Localised otitis externa (furuncle)
Diffuse otitis externa
Malignant otitis externa
Herpes zoster oticus
Otitis externa haemmorhagica
REACTIVE group
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Eczematous otitis externa
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Seborrhoeic otitis externa
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Neurodermatitis

13. Acute localised otitis externa
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Infection of a hair follicle (furuncle)
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begin as folliculitis-->small abscess/furuncle
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Staphylococcus aureus
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Lateral cartilaginous (outer 1/3rd) portion of EAC

14. Acute localised otitis externa (contd...)
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Symptoms – severe pain/discharge/hearing
loss/aural fullness
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O/E – tragal tenderness/oedematous EAC/enlarged,
tender preauricular LN
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Furuncle in posterior meatal wall --> oedema over
mastoid --> obliteration of retroauricular groove

15. Acute localised otitis externa (contd...)
Treatment:
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Early cases without abscess formation,
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Systemic antibiotics
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Topical antibiotics+corticosteroids
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Analgesics/local hot fomentation/ear pack with
10% icthammol glycerine
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If abscess has formed,
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Incision & Drainage
Topical antibiotic ointment with/without oral antibiotics
Recurrent furunculosis
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R/o diabetes, staphylococcal skin infection, nasal
vestibule harbouring staphylococci

16. Acute diffuse otitis externa
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Swimmer's ear
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Commonest form of otitis externa
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Usual pathogens – Pseudomonas aeruginosa,
Staphylococcus aureus, Proteus mirabilis
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Symptoms – pain/itching/aural fullness/hearing loss
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O/E – tenderness/ narrow EAC with congested,
oedematous skin/ clear or purulent exudates

17. Acute diffuse otitis externa (contd...)
Treatment:
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Ear toilet
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Medicated wicks ●
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Acidifying/antiseptic agents – gentian violet
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Antibiotic-steroid prepration
Mild astingent – 8% aluminium acetate/3% silver nitrate
Antibiotics ●
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●
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Topical antibiotics – (neomycin/ciprofloxacin/ofloxacin)
with/without corticosteroids
Broad spectrum systemic antibiotics
Analgesics
Avoid water entry/avoid usind cotton buds/avoid digital
manipulation of ear canal

18. Chronic otitis externa
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●
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Low grade, diffuse infection of EAC persisting
for months/years
Pruritis, dry hypertrophic skin of EAC leading to
post inflammatory stenosis
Causes are bacterial/fungal infections, also
include skin conditions seborrhoeic dermatitis,
psoriasis, neurodermatitis, sensitization to an
topical ear drops

19. Chronic otitis externa (contd...)
Treatment:
GOAL – prevent stenosis & restore normal skin in EAC
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Frequent inspection & debridment of EAC
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Antibiotic-corticosteroid topical applications
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EAC can be painted with gentian violet/ triamcinolone/
nystatin
Treat underlying causes – seborrhoea, psoriasis,
neurodermatitis

20. Chronic otitis externa (contd...)
Surgical treatment:
In case of medical treatment failure with canal stenosis
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Canalplasty with skin grafting – restore canal patency
and hearing
Procedure:
➔
Abnormal skin is removed entirely
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Denuded canal is enlarged using diamond bur
➔
➔
➔
➔
Split thickness graft is harvested from medial surface of
upper arm with a dermatome
Graft placed on exposed suface
'rosebud' type of packing is done over skin graft and left for
2 weeks
Crusting may occur for several weeks, requires removal till
complete healing

21. Chronic otitis externa (contd...)
Preventive measures:
●
●
Patients instructed not to use cotton swabs or
any other objects to canal
Swimmers instructed to use ear plugs and
advised to use alcohol-vinegar (1:1) drops after
swimming

22. Malignant (necrotizing) otitis externa
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Progressive, lethal infection of EAC,
surrounding tissue and skull base
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Elderly diabetic/ immunocompromised pts.
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Pseudomonas aeruginosa

23. Malignant otitis externa (contd...)
Pathophysiology:
●
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Infection begins in EAC --> cellulitis, chondritis,
osteitis, osteomyelitis
May spread to osseus auditory canal & skull
base through fissures of Santorini -->
replacement of compact bone with granulation
tissue
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Facial N paalysis – stylomastoid foramen involvement
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CN IX, X, XI palsies - jugular foramen involvement
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Jugular V thrombosis-->lateral sinus thrombosis

24. Malignant otitis externa (contd...)
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Symptoms:
purulent discharge/excruciating pain/facial N palsy/
CN IX,X,XI palsy
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O/E:
granulation tissue in floor of EAC at bony-cartilaginous
junction is typical otoscopic finding
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Investigations:
C&S of discharge
CT scan
Gallium scan

25. Malignant otitis externa (contd...)
Treatment:
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Hospitilization
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Control of diabetes
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Antibiotics ●
Aminoglycosides + penicillin/cephalosporins
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Quinolones
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Daily debridement of EAC
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Surgery ●
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Debridement of devitalised tissue/bone
Mastoidectomy with facial N decompression /
subtotal petrosectomy

26. Fungal otitis externa (Otomycosis)
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Fungal infection of EAC
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Aspergillus niger – black headed filamented growth
Aspergillus fumigatus – brown
Candida albicans – white/creamy deposits
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Secondary fungal infection may be seen in pts
using topical antibiotics for otitis externa/ middle
ear suppuration

27. Fungal otitis externa (contd...)
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Symptoms:
pruritis/ pain or discomfort in ear/ watery
discharge with musty odour/ ear block
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O/E:
erythematous canal with black/grey/white
fungal mass – 'wet piece of filter paper'

28. Fungal otitis externa (contd...)
Treatment:
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Ear toilet
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Antifungal agents – nystatin/clotrimazole
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2% salicylic acid
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Ear must be kept dry
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Secondary bacterial infections – antibiotic +
steroid prepration
Oral antifungals – refractory to topical agents

29. Herpes zoster oticus
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HSV – most frequent virus to affect EAC
HSV stay dominant in sensory ganglia –
reactivates in decreased immunocompetence
Blisters/vesicles on auricle, EAC, TM
Blisters – short lived, rupture, dry & heal
spontaneously
May develop CN VII, VIII palsy

30. Herpes zoster oticus (contd...)
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'Ramsay Hunt Syndrome' – clinical syndrome
with facial N palsy with or without hearing loss
and dizziness owing to herpes zoster
Treatment:
Self limiting, primarily supportive
Antivirals (acyclovir) & steroids can be used

31. Otitis externa haemmorhagica
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Formation of haemmorhagic bullae on TM and
deep meatus
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Viral / seen in influenza epidemics
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Severe ear pain / blood stain discharge
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Treatment:
Analgesics
Antibiotics – secondary infections

32. Complications – Otitis Externa
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Cellulitis/ Perichondritis/ Chondritis
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Medial canal fibrosis
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Tympanic membrane perforation
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Malignant otitis externa

33. Thank you