This document provides information about otitis externa (OE), including: 1) OE is an inflammation of the external ear canal caused most often by bacterial infection, but sometimes fungi or viruses. Risk factors include water exposure, trauma from cotton swabs, and eczema. 2) Symptoms include ear pain, fullness, discharge, and hearing loss. Examination reveals erythema and tenderness of the ear canal. 3) Treatment involves cleaning the ear canal and using topical antibiotics, corticosteroids, or antifungals depending on the cause. Imaging is not usually needed but may help identify complications like mastoiditis.

1. OTITIS EXTERNA
Fahad zakwan
MD5

2. introduction
• Otitis externa (OE) is an inflammation or
infection of external auditory canal (EAC),
the auricle or both.
• It is a common disease that can be found in
all age groups
• OE usually represents an acute bacterial
infection of the skin of the ear canal but can
also be caused by other bacteria, viruses, or
a fungal infection.

3. •Several factors can contribute to EAC
infection and the development of OE,
including the following:
•Absence of cerumen
•High humidity
•Retained water in ear canal
•Increased temperature
•Local trauma (eg, use of cotton swabs or
hearing aids)

4. • Aquatic athletes are particularly prone to the
development of OE because repeated exposure to water
results in removal of cerumen and drying of the EAC.
• Retained water in the ear canal can cause maceration of
the skin and a milieu conducive to bacterial or fungal
proliferation.
• OE occurs more often in the summer months, when
swimming is more common, and it is also common in
tropical areas.
• Individuals with allergic conditions (eg, eczema, allergic
rhinitis, and asthma) are also at significantly higher risk for
OE

5. Classification
OE may be classified as follows:
•Acute diffuse OE
•Acute localized OE
•Chronic OE
•Eczematous (eczematoid) OE
•Necrotizing (malignant) OE
•Otomycosis

6. Acute diffuse OE
• This is the most common form of OE, typically seen
in swimmers;
• it is characterized by rapid onset (generally within
48 hours) and symptoms of EAC inflammation (e.g,
otalgia, itching, or fullness, with or without hearing
loss or jaw pain) as well as:
• tenderness of the tragus or pinna or diffuse ear edema
or erythema or both, with or without otorrhea,
• regional lymphadenitis,
• tympanic membrane erythema, or
• cellulitis of the pinna

8. Acute localized OE
•This condition, also
known as furunculosis, is
associated with
infection of a hair follicle

9. Chronic OE
•This is the same as
acute diffuse OE
but is of longer
duration (>6 weeks)

10. Eczematous (eczematoid) OE
•This encompasses various
dermatologic conditions (eg,
atopic dermatitis, psoriasis,
systemic lupus erythematosus,
and eczema) that may infect the
EAC and cause OE

11. Necrotizing (malignant) OE
• This is an infection that extends into the
deeper tissues adjacent to the EAC;
• it primarily occurs in adult patients who are
immunocompromised (eg, as a result of
diabetes mellitus or AIDS) and is rarely
described in children;
• it may result in cases of cellulitis and
osteomyelitis

12. Otomycosis
•Infection of the
ear canal
secondary to
fungus species
such as Candida
or Aspergillus

13. Pathophysiology
• OE is a superficial infection of the skin in the EAC.
• The processes involved in the development of OE
can be divided into the following 4 categories:
• Obstruction (eg, cerumen buildup, surfer’s exostosis, or
a narrow or tortuous canal), resulting in water retention
• Absence of cerumen, which may occur as a result of
repeated water exposure or overcleaning the ear
canal
• Trauma
• Alteration of the pH of the ear canal

14. • If moisture is trapped in the EAC, it may cause
maceration of the skin and provide a good
breeding ground for bacteria.
• This may occur after swimming (especially in
contaminated water) or bathing—hence the
common lay term “swimmer’s ear.”
• It may also occur in hot humid weather.
• Obstruction of the EAC by excessive cerumen,
debris, surfer’s exostosis, or a narrow and tortuous
canal may also lead to infection by means of
moisture retention.

15. • Trauma to the EAC allows invasion of bacteria into
the damaged skin.
• This often occurs after attempts at cleaning the ear
with a cotton swab, paper clip, or any other utensil
that can fit into the ear.
• Once infection is established, an inflammatory
response occurs with skin edema.
• Exudate and pus often appear in the EAC as well.
• If severe, the infection may spread and cause a
cellulitis of the face or neck.

16. Etiology
• OE is most often caused by a bacterial pathogen;
other varieties include fungal OE (otomycosis) and
eczematoid (psoriatic) OE.
• The most common causative bacteria are:
• Pseudomonas species (38% of all cases),
• Staphylococcus species,
• Anaerobes,
• gram-negative organisms.

17. •Fungal OE may result from
overtreatment with topical
antibiotics or may arise de novo from
moisture trapped in the EAC.
•It is caused by Aspergillus 80-90% of
the time;
•Candida and other organisms have
also been isolated.

18. •Eczematoid (psoriatic) OE is
associated with the following
conditions:
•Eczema
•Seborrhea
•Neurodermatitis
•Contact dermatitis from earrings or
hearing aid use
•Sensitivity to topical medications

19. • Necrotizing OE occurs in patients who are
immunocompromised and represents a true
osteomyelitis of the temporal bone.
• Risk factors for OE include the following:
• Previous episodes of OE
• Swimming, diving, or participating in aquatic activities
• Use of earplugs or probing of the EAC
• Hot, humid weather
• Use of a hearing aid
• Coexistence of eczema, allergic rhinitis, or asthma
• Comorbidities such as diabetes mellitus, AIDS,
leukopenia, or malnutrition

20. Epidemiology
• Although the infection can affect all age groups,
OE appears to be most prevalent in the older
pediatric and young adult population, with a peak
incidence in children aged 7-12 years
• OE affects both sexes equally.
• No racial predilection has been established,
though people in some racial groups have small
ear canals, which may predispose them to
obstruction and infection.

21. History
Patients with otitis externa (OE) may complain of the
following:
• Otalgia, ranging from mild to severe, typically progressing
over 1-2 days
• Hearing loss
• Ear fullness or pressure
• Tinnitus
• Fever (occasionally)
• Itching (especially in fungal OE or chronic OE)

22. • Severe deep pain – If this is experienced by a patient
who is immunocompromised or diabetic, be alerted to
the possibility of necrotizing (malignant) OE
• Discharge – Initially, the discharge may be clear and
odorless, but it quickly becomes purulent and foul-
smelling
• Bilateral symptoms (rare)
• Frequently, a history of exposure to or activities in
water (e.g, swimming, surfing, and kayaking)
• Usually, a history of preceding ear trauma (e.g,
forceful ear cleaning, use of cotton swabs, or water in
the ear canal)

23. Physical Examination
• The key physical finding of OE is pain
upon palpation of the tragus (anterior
to ear canal) or application of traction
to the pinna (the hallmark of OE).
• Examination reveals erythema, edema,
and narrowing of the external auditory
canal (EAC), and a purulent or serous
discharge may be noted.
• Conductive hearing loss may be
evident.
• Cellulitis of the face or neck or
lymphadenopathy of the ipsilateral
neck occurs in some patients.

24. • The tympanic membrane may be difficult to visualize and
may be mildly inflamed, but it should be normally mobile
on insufflation.
• Eczema of the pinna may be present.
• Fungal OE results in severe itching but typically causes less
pain than bacterial OE does. A thick discharge that may
be white or gray is often present.
• pseudomonal infection produces purulent otorrhea that
may be green or yellow,
• Aspergillus otomycosis looks like a fine white mat topped
by black spheres. Upon close examination, the discharge
may contain visible fungal elements (eg, spores or
hyphae) or have a fuzzy appearance.

26. Complications
Complications of OE are rare and may include the
following:
• Necrotizing OE (the most significant complication)
• Mastoiditis
• Chondritis of the auricle (from spread of acute OE to the
pinna, particularly in patients with newly pierced ears)
• Bony erosion of the base of the skull
• Central nervous system (CNS) infection
• Cellulitis or lymphadenitis

27. Differential diagnosis
• Ear canal trauma
• Otitis media
• Hearing loss
• Intracranial abscess
• Furuncle
• Preauricular cyst and fistula
• Lacerations
• Atopic dermatitis
• Cerumen impaction
• Foreign body

28. investigations
• The patient’s history and physical examination
usually provide sufficient information to allow the
clinician to make the diagnosis of otitis externa
(OE). Most persons with OE are treated empirically.
• Thus, laboratory studies typically are not needed.
However, Gram staining and culture of any
discharge from the auditory canal may be helpful
if the patient is immunocompromised, if the usual
treatment measures are ineffective, or if a fungal
cause is suspected.

29. Lab studies
•Gram staining and
culture of the canal
discharge
•Blood glucose
check/urine dipstick test

30. CT, MRI, Bone Scan, and Gallium
Scan
• Imaging studies are not required for most cases of OE. However,
radiologic investigation may be helpful if an invasive infection such as
necrotizing (malignant) OE is suspected or if the diagnosis of
mastoiditis is being considered.
• High-resolution computed tomography (CT) is preferred and better
depicts bony erosion.[6] Radionucleotide bone scanning and gallium
scanning have been used to make the diagnosis. Magnetic resonance
imaging (MRI), though not used as often, may be considered
secondarily or if soft tissue extension is the predominant concern.[7]

31. Otoscopy
• In cases of external ear
infection, otoscopic
examination must be
performed in
conjunction with
evaluation of related
structures (eg, the
external ear and the
head and neck).

33. The otoscope
• An otoscope consists of a head and a handle and is used
to examine the external auditory canal (EAC), the
tympanic membrane, and the middle ear.
• A magnifying lens enhances the clinician’s view.
• The following 2 types of head are available for the
otoscope:
• Diagnostic head – This head is fixed to the otoscope and does
not allow the use of microinstruments through the scope
• Working (operating head) – This head has a magnifying lens that
can slide to the side, enabling passage of microinstruments
through the speculum into the EAC and the middle ear

35. • For optimal viewing of the tympanic membrane in an
adult, retract the auricle posteriorly and superiorly to
straighten the EAC;
• for optimal viewing in a child, pull the auricle posteriorly.
• Remove any debris or cerumen to allow an adequate
examination.
• Proceed with the examination as follows:
• First, examine the EAC for masses, skin changes, and
otorrhea
• Next, examine all parts of the tympanic membrane
• Next, assess the motion of the tympanic membrane by
means of pneumatic otoscopy
• Finally, attempt a thorough examination of the middle
ear contents through the tympanic membrane.

37. TREATMENT
Primary treatment of otitis externa (OE)
involves:
• management of pain,
• removal of debris from the external auditory
canal (EAC),
• administration of topical medications to
control edema and infection, and
• avoidance of contributing factors.

38. • Most cases can be treated with over-the-
counter analgesics and topical eardrops.
• Commonly used eardrops include:
•acetic acid drops, which change the pH of
the ear canal;
•antibacterial drops, which control bacterial
growth; and
•antifungal preparations.
•topical steroid drops.

39. Removal of Debris From Ear Canal
• Removal of debris from the ear canal improves the
effectiveness of the topical medication.
• Gentle cleaning with a soft plastic curette or a
small Frazier suction tip under direct vision is
appropriate.
• Irrigation with a mix of peroxide and warm water
may be useful for removing debris from the canal,
but only if the tympanic membrane is intact.
• Any water instilled must be removed to keep from
exacerbating the condition.

40. Pharmacologic therapy
Available antiseptic preparations includes:
• acetic and boric acids,
• phenol,
• aluminum acetate,
• gentian violet,
• thymol,
• alcohol.

41. Available antibiotic
preparations include:
•ofloxacin,
•ciprofloxacin,
•chloramphenicol,
•gentamicin

42. •Treat underlying course if it known.
•Preparations with steroids help to
reduce edema and otalgia.
•Systemic antibiotics are indicated for
infections that spread beyond the EAC.
•Fungal infections need antifungal
agents such as nystatin or clotrimazole.
•Eczematous reactions of the pinna
require application of anti allergic
creams or ointments

43. •Medication may be instilled as drops twice a
day, painted on the meatal walls with cotton
wool on a wire wool carrier, inserted on an
impregnated gauze wick, or insufflated as a
powder after toilet.
•Systemic antibiotics are never necessary.
•Topical preparations should not be used for
long periods (7–10 days at most).
•There is, however, a case for applying drops
intermittently (for example once a week) to
try to prevent repeated relapses.

44. Surgical Debridement and Drainage
• Surgical debridement of the ear canal is usually
reserved for necrotizing OE or for complications of
OE (eg, external canal stenosis).
• It is often necessary in more severe cases of OE or
in cases where a significant amount of discharge is
present in the ear.
• An otolaryngologist usually performs debridement
using magnification and suction equipment.
• Debridement is the mainstay of treatment for
fungal infections.

45. •Occasionally, an abscess forms in
the ear canal; this usually occurs in
cases of OE caused by S aureus.
•Treatment of the abscess is often
accomplished by means of a simple
incision and drainage procedure
that is usually performed by an
otolaryngologist using a needle or a
small blade.

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