Clinical Notes : ENT
126. Acute Otitis Externa

Acute Otitis Externa
Definition
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Otitis externa is inflammation of the external ear canal
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Acute if it has lasted for 3 weeks or less.
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Chronic if it has lasted for longer than 3 months.
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Diffuse (swimmer's ear, or tropical ear)
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widespread inflammation of the skin and subdermis of the external ear canal, which can extend to the external ear and the tympanic membrane (ear drum)
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Localized (furunculosis)
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infection of a hair follicle that can progress to become a furuncle (boil) in the ear canal
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Eczematous (eczematoid)
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Encompasses various dermatologic conditions that may infect the External Auditory Canal
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atopic dermatitis
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psoriasis
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systemic lupus erythematosus
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eczema
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Necrotising (malignant)
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aggressive infection that spreads into the bone surrounding the ear canal (the mastoid and temporal bones
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fatal condition without treatment
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Otomycosis
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Infection of the ear canal from a fungal species
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Incidence
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Otitis externa is common and more than 1% of people will be diagnosed with the condition each year.
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It affects people of all ages, but incidence peaks at age 7–12 years.
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Etiology
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Bacterial infection
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most common cause of otitis externa
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Pseudomonas aeruginosa or Staphylococcus aureus are the most prevalent pathogens.
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Fungal infections
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Superficial fungal infection is usually due to Aspergillus species, or Candida albicans.
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Deeper infections (of the stratum corneum) are due to epidermophyton, trichophyton, or microsporum genera.
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Seborrhoeic dermatitis
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may affect the ears in isolation, or be associated with one or more of the following: dandruff, eyebrow scaling, blepharitis, or facial redness and scaling.
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Contact dermatitis
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topical medications (for example neomycin ear drops)
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hearing aids
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earplugs.
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Allergic contact dermatitis
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usually has a sudden onset and presents with erythematous, itchy, oedematous, and exudative lesions.
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Irritant contact dermatitis
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tends to have an insidious onset with lichenification.
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Trauma
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caused by scratching, aggressive cleaning, ear syringing, foreign objects in the ear, and the use of cotton buds, hearing aids or ear plugs.
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Environmental factors
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high temperature and/or high humidity
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perspiration
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swimming (especially in polluted water)
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Regular cleaning of the ear canal
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alkaline eardrops
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soapy deposits
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cerumen creates a slightly acidic pH that inhibits infection (especially by P aeruginosa) but can be altered by water exposure, aggressive cleaning
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removes cerumen, which is an important barrier to moisture and infection
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Risk factors for malignant otitis include
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diabetes
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radiotherapy to the head and neck.
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compromised immunity, such as from HIV/AIDS, chemotherapy, or chronic kidney disease
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Diagnosis
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Signs:
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The ear canal or external ear, or both, are red, swollen, or eczematous with shedding of the scaly skin.
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Swelling in the ear canal is typical of an early presentation of localized otitis externa; later the swelling has a white or yellow centre filled with pus; occasionally this progresses and the swelling eventually completely occludes the ear canal.
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Discharge (serous or purulent) may be present in the ear canal.
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Inflamed eardrum, which may be difficult to visualize if the ear canal is narrowed or filled with debris.
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Symptoms include any combination of the following:
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Itch (typical).
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Severe ear pain, disproportionate to the size of the lesion (typical).
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Pain made worse when the tragus or pinna is moved, or when an otoscope is inserted (typical).
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Tenderness on moving the jaw.
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Tender regional lymphadenitis — may be present (less common).
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Sudden relief of pain if the furuncle in localized otitis externa bursts (rare).
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Loss of hearing if there is sufficient swelling to occlude the ear canal (rare).
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Diffuse (swimmers ear)

Localised (furunculosis)

Eczematoid



Malignant
Otomycosis
Otomycosis
Management
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Treat the pain if present:
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analgesic
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paracetamol or ibuprofen
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plus codeine for severe pain
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application of local heat (for example a warm flannel).
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These measures are sufficient for most cases of localized otitis externa as folliculitis is usually mild and self-limiting
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Topical antimicrobials are beneficial
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use topical antibiotic with or without a topical corticosteroid
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use for a minimum of 7 days
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if symptoms persist, continue up to a maximum of 14 days
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Quinolone containing preparations (for example ciprofloxacin, or ofloxacin) only require twice daily dosing
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can be used in people with a perforated ear drum
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Topical acetic acid 2% spray
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is safe and effective treatment
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can be used for mild cases
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Chloramphenicol ear drops
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not recommended as they contain propylene glycol which causes contact dermatitis in about 10% of people
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Only consider an oral antibiotic if
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medical condition which is associated with increased risk of severe infection (such as diabetes mellitus, or compromised immunity).
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systemic signs of infection, such as fever.
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severe infection, or at high risk for severe infection
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for example if furunculosis or cellulitis spreads beyond the ear canal to the pinna, neck, or face.
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If an oral antibiotic is required, consider are a 7-day course of flucloxacillin, or clarithromycin (if the person is allergic to penicillin)
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If fungal infection is suspected (signs of fungal growth in the ear canal):
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Prescribe a topical antifungal preparation
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Clotrimazole 1% solution.
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Acetic acid 2% spray (unlicensed use).
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Clioquinol and a corticosteroid
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Seek specialist advice if there is inadequate response.
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If the cause is Irritant, or allergic dermatitis
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avoid contact with the irritant or allergen
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prescribe a topical corticosteroid.
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Seborrhoeic dermatitis — treat topically with an antifungal/corticosteroid combination
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Drain pus
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if pus is causing severe pain and swelling
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rarely required.
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usually requires referral
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a small pustule near the entrance to the ear canal may be drained by incising it with a surgical needle
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Manage any aggravating or precipitating factors
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diabetes mellitus
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dermatitis
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ear trauma
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Consider the need for investigations
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ear swab proves rarely useful, but may be necessary if symptoms are persistent or recurrent.
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Provide appropriate self-care advice to aid recovery and reduce risk of recurrence
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keep the ears clean and dry
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avoid the use of cotton buds
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Treat generalized skin conditions such as eczema
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Seek specialist advice if
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symptoms persist
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contact sensitivity is suspected
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ear canal is occluded.
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Refer to secondary care if
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extensive cellulitis
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extreme pain or discomfort
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considerable discharge or extensive swelling of the auditory canal
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sufficient earwax or debris to obstruct the application of topical medication
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Follow up
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is not usually necessary,
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recommended for people with
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severe otitis externa
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chronic otitis externa
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diabetes mellitus
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compromised immunity.
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Management of localized otitis externa includes:
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Advising people to apply local heat using a warm flannel — this may be sufficient, as folliculitis is usually mild and self-limiting.
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Considering incision and drainage if pus is causing severe pain and swelling — this usually requires referral, although a small pustule near the entrance to the ear canal may be drained by incising it with a surgical needle.
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Urgent admission should be arranged for people with suspected malignant otitis.
Self-care
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Keep ears clean and dry
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avoid use of cotton buds
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use a hair dryer (at the lowest heat setting) to dry the ear canal after hair washing, bathing, or swimming
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swimming
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use ear plugs and or a tight fitting cap
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people with acute otitis externa should abstain from water sports for at least 7 to 10 days
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consider using acidifying ear drops or spray (such as EarCalm®) shortly before swimming, after swimming, and at bedtime
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Summary tables: infections in primary care
Management and treatment of common infections:
guidance for consultation and adaptation

AAFP
Acute Otitis Externa
September 2014
NICE CSK Guidelines
Otitis Externa
February 2018
Clinical practice guideline: acute otitis externa
American Academy of Otolaryngology
2014
Otitis Externa
BMJ Best Practice
February 2019

Topical ear preparations available in the ROI for treating otitis externa :

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