Dr. T. Balasubramanian M.S.
Synonyms: Infections of the external ear
Definition: Otitis externa is defined as
infection / inflammation of the external auditory canal / auricle.
It can range in its severity between mild infection to a more severe
one. It is one of the most common disease involving the external
Otitis externa is classified as follows:
1. Acute diffuse otitis externa (commonly caused
2. Acute localised otitis externa (commonly
3. Chronic otitis externa
4. Eczematous otitis externa
5. Fungal otitis externa
6. Malignant otitis externa
Predisposing factors responsible for otitis
Under normal conditions the skin lining the
external auditory canal is well protected by its self cleansing
mechanism. In diseased conditons several factors may come into play
in the pathogenesis of otitis externa.
1. Absence of cerumen: The cerumen plays an
important role in the protection of the external canal. It protects
the external canal from moisture. It also has anti bacterial
properties which helps in the protection of the external canal. The
cerumen also lowers the pH of the external canal making it difficult
for the bacterial pathogens to colonize.
2. Removal of cerumen by ear buds: is one of the
common causes of otitis externa. The act of removal traumatises the
skin lining of the external canal making it vulnerable to
3. Frequent exposure to water: external canal
when constantly bathed in water loses its ability to protect itself.
The presence of water macerates the skin lining of the external
canal and also increase the pH of the external canal making it more
favourable for bacterial colonisation. This condition is common in
Acute diffuse otitis externa:
This is also known as the swimmers ear. This is
an inflammatory condition involving the external canal in a diffuse
manner. This condition is common in swimmers
because of the propensity for the external canal to be exposed to
water for long durations. This exposure leads to maceration of the
external canal skin, and also lowers the pH of the external canal
providing an environment favorable to infections.
1. Itching in the external canal
2. Tenderness on palpation
3. Aural fullness rarely occur due to the
reduction in size of the external canal lumen due to oedema
4. Rarely stenosis of the external canal may
occur causing accumulation of debris and secretions
1. Erythema of the external canal
2. Oedema of external canal
3. Secretions from the external canal (weeping
4. Pain on mastigation
5. Pulling of helix in a postero superior
direction cause pain
6. In advanced cases fever and lymphadenopathy
may occur (pre and post auricular nodes may be involved)
Stages of acute diffuse otitis externa:
Preinflammatory stage: is characterised by
intense itching, edema and sensation of fullness in the
Inflammatory stage: may be divided into mild,
moderate and severe.
Mild acute inflammatory stage: here the cardinal
features are increased itching, pain, mild erythema and oedema of
the external canal skin. At later stages exfoliation of skin with
minimal amount of cloudy secretions may be seen in the external
Moderate acute inflammatory stage: in this stage
the itching and tenderness of the external canal intensifies. The
external canal is narrowed due to oedema and accumulation of
Severe acute inflammatory type: In this stage
pain becomes intolerable to such an extent the patient may refuse to
eat, the lumen of the external canal becomes totally obliterated due
to oedema and accumulated epithelial debris. Otorrhoea may become
purulent. In addition regional nodes may also be involved.
Infections from the external canal may involve the parotid gland via
the fissure's of santorini.
Common organisms involved: Psuedomonas aeruginosa
and staphylococcus aureus are commonly cultured from the external
canal of these patients. The normal commensols like staphylococcus
epidermidis and corynebacteria are conspicously absent.
The aim is two fold:
1. Resolving the infection
2. Promoting the external canal skin's recovery
to its original state.
Firstly the canal is cleaned atraumatically by
gentle suctioning and debridement under microscope.
Topical hydrogen peroxide solution instilled will
help the process of debridement.
A cotton wick dipped in I.G. paint can be
inserted in to the external canal and allowed to stay for a day.
This will reduce the external canal skin oedema and will increase
the size of the meatus. Ear drops containing a mixture of neomycin
and 1% hydrocortisone may be instilled as ear drops atleast three
times a day. In addition to the antibiotic and antiinflammatory
effects this drug reduces the pH of the external canal making it
more resistant to the organisms.
In severe cases oral antibiotics and anti
inflammatory drugs can be resorted to. Quinolones are commonly used
Acute localised otitis externa: This
condition is otherwise known as furunculosis or circumscribed otitis
externa. This is a localised infection usually found to involve the
lateral 1/3 of the external canal. It also has a propensity to
involve the posterior superior aspect of the external canal. This is
caused due to obstruction of the apopilosebaceous units found
extensively in this area.
Trauma to skin in this area followed by infection
is commonly attributed cause. The organism responsible is commonly
1. Localised pain
2. Localised itching
3. Purulent discharge if the abscess
4. If oedema or abscess occludes the external
canal hearing loss can occur.
showing furuncle of external auditory canal
1. Erythema of the skin
2. Localised abscess formation
If the abscess is pointing it can be treated by
incision and drainage. Oral antibiotics should be used. The
preferred drug of choice is penicillin of first generation
cephalosporins. Anti inflammatory drugs can be used to reduce
inflammation and pain.
These patients must be advised to cut their nails
short and to keep their hands clean, since this is the commonest
route of infection.
Chronic otitis externa:
This is a chronic infection / inflammation
involving the skin lining of the external canal. There is thickening
of the skin lining of the external canal due to persistent low grade
infection / inflammation.
1. Unrelenting pruritus
2. Mild pain
3. Presence of dry skin in the external
1. Asteatosis (lack of ceumen)
2. Hypertrophic external canal skin
3. Presence of dry flaky skin in the external
4. Mild tenderness on ear manupulation
5. Rarely muco purulent otorrhoea
Cultures from the external canal of these
patients are highly unreliable because they would have been using
various antibiotic drops to surmount the problem.
Involves extensive use of acetic acid ear drops.
This helps to reduce the pH of the skin lining the external canal
making it more resistant to bacterial infections. In intractable
cases steriod drops can be tried. Antibiotic drops may not be useful
in these patients.
Surgery is indicated in extreme cases. A
canalplasty is performed to widen the external canal. The involved
skin may be removed to be replaced by a split thickness graft.
Eczematous otitis externa:
This condition includes various dermatologic
conditions involving the skin of the external canal.
It may range from atopic dermatitis, contact dermatitis,
seborrheic dermatitis, neuro dermatitis, infantile eczema etc.
This condition is characterised by intense
itching, infact this could be the only complaint of the patient. On
examination, erythema of the external canal skin may be seen. There
may also be associated scaling and oozing from the canal
Success lies in the management of the underlying
It is also known as Fungal otitis externa. This
is the commonest type of otitis externa in tropical countries. This
condition is associated with increased ear canal moisture, or
following treatment of otitis external by prolonged use of topical
antibiotics. The protective cerumen layer is absent in these
patients. This condition is more common in diabetics.
1. Intense itching
2. Pain when otitis externa is
3. Blocking sensation due to the presence of
1. Inflammed external canal skin
2. External canal tenderness
3. Fungal debris (black in case of aspergillus
and white in the case of candida). Invariably the infection is mixed
The condition is managed by careful aural
toileting to remove the fungal balls. The best way to remove fungus
from the ear canal is by aural syringing. Antifungal ear drops of
clotrimazole can be administered. If secondary infections are
present oral antibiotics and antiinflammatory drugs may be resorted
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