1. OTITIS EXTERNA
Dr. Mohammed Shafeeq

2. Definition
● 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
● Bottom of concha to TM
● 24mm along posterior border
● Divided into:
● Outer/cartilaginous part
● Inner/bony part
● Outer part – upwards, backwards & medially
● Inner part – downwards,forwards & medially

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

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

6. Pathogenesis
Clinical course of otitis externa can be divided
into:
● Pre-inflammatory stage
● Acute inflammatory stage
● 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
● Anatomical - narrow EAC
(hereditary/iatrogenic/exostoses), obstruction of
normal meatus (keratosis obturans/FB/hearing aids)
● Dermatological - eczema,seborrhoeic dermatitis
● Allergic – long term topical medications
● Physiological – humidity, immunocompromised
● Traumatic – skin maceration(swimming), ear
probing, laceration, radiotherapy
● Microbiological – active COM, exposure to
P.aeruginosa or fungi

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

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

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

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

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

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

17. Acute diffuse otitis externa (contd...)
Treatment:
● Ear toilet
● Medicated wicks -
● Antibiotic-steroid prepration
● Acidifying/antiseptic agents – gentian violet
● Mild astingent – 8% aluminium acetate/3% silver nitrate
● Antibiotics -
● 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
● 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
● Frequent inspection & debridment of EAC
● Antibiotic-corticosteroid topical applications
● 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
● Canalplasty with skin grafting – restore canal patency
and hearing
Procedure:
➔ Abnormal skin is removed entirely
➔ 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
● Progressive, lethal infection of EAC,
surrounding tissue and skull base
● Elderly diabetic/ immunocompromised pts.
● Pseudomonas aeruginosa

23. Malignant otitis externa (contd...)
Pathophysiology:
● 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
● Facial N paalysis – stylomastoid foramen involvement
● CN IX, X, XI palsies - jugular foramen involvement
● Jugular V thrombosis-->lateral sinus thrombosis

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

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

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

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

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

29. Herpes zoster oticus
● 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...)
● '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
● Formation of haemmorhagic bullae on TM and
deep meatus
● Viral / seen in influenza epidemics
● Severe ear pain / blood stain discharge
● Treatment:
Analgesics
Antibiotics – secondary infections

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

33. Thank you