Diseases of external ear

Diseases of external ear

Dr T Balasubramanian

drtbalu's otolaryngology online

Anatomy of external canal
● Length 2.5 cms
● Outer 1/3 cartilagenous
● Inner 2/3 bony
● Postero superior wall is shorter than antero
inferior wall
● It is not a straight tube


Classification
● Congenital
● Inflammatory
● Reactive
● Trauma
● Tumors


Congenital conditions
● Preauricular sinus
● Congenital swellings (Pinna)
● Collaural fistula
● Congenital anamolies (Pinna)
● Atresia external canal
● Congenital tumors of external canal


Preauricular sinus


Preauricular sinus (synonyms)
● Preauricular pit
● Preauricular sinus
● Preauricular tract
● Helical fistula
● Preauricular cyst


Pinna (Embryology)
● Begins during the 6th week of gestation
● Begins from 6 hillocks (Hillocks of His)
● 3 hillocks arise from caudal border of I arch
● Other 3 arise from the cephalic border of II
arch


Embryology of Pinna


Preauricular sinus theories
● Embryological fusion: Incomplete fusion of
Hillocks
● Ectodermal infolding: Isolated ectodermal
infolding
● Incomplete closure of dorsal part of first
pharyngeal groove: (accepted)


Mode of inheritance
● Autosomal dominant
● Varying degrees of penetrance
● Chromosome 8q 11 (postulated)


Preauricular sinus (syndromes)
● BOR syndrome (Branchio oto renal)
● Branchio oto urethral
● Branchio otic syndrome
● Branchio otocostal syndrome
● Cat eye syndrome
● Trisomy 22


Preauricular sinus clinical
features
● Seen as a small pit along the anterior margin
of ascending limb of helix
● The tract usually blends with the
perichondrium of auricle
● Sinus tract is usually superior and lateral to
facial nerve and parotid gland
● Subcutaneous cyst formation in the area is
common

Common sites of preauricular
sinus


Management
● Complete removal
with the tract
● Leaving behind
remanant leads to
recurrence


Complete resource can be found
here

http://www.drtbalu.co
.in/preauricular.html


Congenital swellings of pinna
● Dermoid
● Hemangiomas
● Lymphangiomas


Collaural fistula
● This is an anamaly of first branchial cleft
● One opening in the floor of external meatus
and another one behind the angle of mandible
close to the anterior border of sternomastoid
muscle
● Fistula passes through parotid gland close to
facial nerve branches


Congenital anamolies of pinna

● Anotia
● Microtia
● Melotia
● Polyotia


Congenital atresia of external
meatus
● Very rare congenital disorder
● Caused by failure of canalization of first
branchial cleft
● Bony atretic plate may be present at the level
of ear drum
● Ossicular malformations common


Inflammatory conditions of pinna
● Erysipelas
● Perichondritis
● Aural seroma


Erysipelas
● St. Anthony's fire
● Caused by streptococcus hemolyticus
infection of skin of pinna
● Pinna appears reddish and oedematous
● Systemic symptoms (common)


Perichondritis Pinna
● Inflammation of perichondrial lining of pinna
● Can follow trauma to ear
● Pinna enlarged
● Cauliflower ear can be caused


Furunculosis
● Staph infection of
hair follicle present in
the cartilagenous
portion of external
canal
● Pain
● Tragal sign +


Furunculosis (clinical features)
● Swelling of external canal
● Tenderness
● Tragal sign +
● Ear drum normal
● Post aural sulcus obliterated
● Regional nodes enlarged and tender


Furunculosis (Management)
● Broad spectrum antibiotics
● Anti inflammatory drugs
● Diabetes should be ruled out


Malignant otitis externa
● Severe form of otitis externa caused by
pseudomonas
● Extensive destruction of adjacent tissues
● Facial palsy is also common
● Skull base involvement is also common


Malignant otitis externa


Otomycosis


Otomyosis (clinical features)
● Irritation
● Itching
● Dull pain / discharge
● Ear block


Otomycosis (management)
● Keeping the ear dry
● Removal of fungal mass
● Antifungal ear drops (clotrimazole)
● Anti inflammatory drugs


Ramsay Hunt Syndrome
● Caused by Herpes zoster virus
● Blisters in external auditory canal
● Otalgia
● Lower motor neuron type facial paralysis


Ramsay Hunt syndrome


Reactive conditions
● Eczematous otitis externa
● Seborrhoeic otitis externa
● Neurodermatitis


Traumatic conditions
● Hematoma
● Frost bite
● Pseudo cyst pinna


Exostosis
● Occurs in the bony meatus
● Usually multiple
● When single occurs at the bony cartilagenous
junction
● Associated with swiming
● Usually asymptomatic


Adenoma external canal
● Arises from sebaceous glands in the
cartilagenous portion of external canal
● Ceruminoma arising from ceruminous glands


Malignant lesions
● Basal cell carcinoma
● Squamous cell carcinoma


Miscellaneous
● Cerumen
● Keratosis obturans
● Foreign bodies – animate and inanimate


Keratosis obturans
● Accumulation of
desquamated kerain
in external canal
● Expands the external
canal
● Due to abnormal
epithelial migration


Keratosis obturans types
● Inflammatory type
● Silent type
● Primary auditory canal cholesteatoma – due to
trauma involving bone of external canal


Keratosis obturans clinical
features
● Otalgia
● Conductive hearing loss
● Associated bronchitis / sinusitis


Other resources
● Www.drtbalu.com
● Www.drtbalu.co.in
● http://www.otolaryngologyonline.net/
● http://otolaryngology.co.in/exam/


Thank you


Diseases of external ear

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