Clinical Notes : ENT

126. Acute Otitis Externa

otitis externa 1.jpg

Acute Otitis Externa

 

Definition

 

  • Otitis externa is inflammation of the external ear canal

    • Acute if it has lasted for 3 weeks or less.

    • Chronic if it has lasted for longer than 3 months.

​​

  • Diffuse (swimmer's ear, or tropical ear)​

    • 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)

 

  • ​Localized (furunculosis)

    • infection of a hair follicle that can progress to become a furuncle (boil) in the ear canal

 

  • Eczematous (eczematoid)

    • Encompasses various dermatologic conditions that may infect the External Auditory Canal 

      • atopic dermatitis

      • psoriasis

      • systemic lupus erythematosus

      • eczema

 

  • Necrotising (malignant)

    • aggressive infection that spreads into the bone surrounding the ear canal (the mastoid and temporal bones

      • fatal condition without treatment

 

  • Otomycosis

    • Infection of the ear canal from a fungal species

 

Incidence

  • Otitis externa is common and more than 1% of people will be diagnosed with the condition each year.

    • It affects people of all ages, but incidence peaks at age 7–12 years.

 

​​Etiology

  • Bacterial infection

    • most common cause of otitis externa

    • Pseudomonas aeruginosa or Staphylococcus aureus are the most prevalent pathogens.

 

  • Fungal infections

    • Superficial fungal infection is usually due to Aspergillus species, or Candida albicans.  

    • Deeper infections (of the stratum corneum) are due to epidermophyton, trichophyton, or microsporum genera.

 

  • Seborrhoeic dermatitis

    • 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.

 

  • Contact dermatitis

    • topical medications (for example neomycin ear drops)

    • hearing aids

    • earplugs.

 

  • Allergic contact dermatitis 

    • usually has a sudden onset and presents with erythematous, itchy, oedematous, and exudative lesions.

 

  • Irritant contact dermatitis 

    • tends to have an insidious onset with lichenification.

 

  • Trauma

    • caused by scratching, aggressive cleaning, ear syringing, foreign objects in the ear, and the use of cotton buds, hearing aids or ear plugs.

 

  • Environmental factors

    • high temperature and/or high humidity

    • perspiration

    • swimming (especially in polluted water)

  • Regular cleaning of the ear canal

    • alkaline eardrops

    • soapy deposits

    • cerumen creates a slightly acidic pH that inhibits infection (especially by P aeruginosa) but can be altered by water exposure, aggressive cleaning

    • removes cerumen, which is an important barrier to moisture and infection

  • Risk factors for malignant otitis include

    • diabetes

    • radiotherapy to the head and neck.

    • compromised immunity, such as from HIV/AIDS, chemotherapy, or chronic kidney disease

 

Diagnosis

  • Signs:

    • The ear canal or external ear, or both, are red, swollen, or eczematous with shedding of the scaly skin.

    • 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.

    • Discharge (serous or purulent) may be present in the ear canal.

    • Inflamed eardrum, which may be difficult to visualize if the ear canal is narrowed or filled with debris.

 

  • Symptoms include any combination of the following:

    • Itch (typical). 

    • Severe ear pain, disproportionate to the size of the lesion (typical).

    • Pain made worse when the tragus or pinna is moved, or when an otoscope is inserted (typical).

    • Tenderness on moving the jaw.

    • Tender regional lymphadenitis — may be present (less common).

    • Sudden relief of pain if the furuncle in localized otitis externa bursts (rare).

    • Loss of hearing if there is sufficient swelling to occlude the ear canal (rare).

otitis externa 2.jpg

Diffuse (swimmers ear)

otitis externa 3.png

Localised (furunculosis)

otitis externa 7.png

Eczematoid

otitis externa 4.png
otitis externa 5.png
otitis externa 6.png

Malignant

Otomycosis

Otomycosis

 

Management

  • Treat the pain if present:

    • analgesic

      • paracetamol or ibuprofen

      • plus codeine for severe pain

    • application of local heat (for example a warm flannel).

    • These measures are sufficient for most cases of localized otitis externa as folliculitis is usually mild and self-limiting

  • Topical antimicrobials are beneficial

    • use topical antibiotic with or without a topical corticosteroid

    • use for a minimum of 7 days

      • if symptoms persist, continue up to a maximum of 14 days

    • Quinolone containing preparations (for example ciprofloxacin, or ofloxacin) only require twice daily dosing

      • can be used in people with a perforated ear drum

    • Topical acetic acid 2% spray

      • is safe and effective treatment

      • can be used for mild cases

    • Chloramphenicol ear drops

      • not recommended as they contain propylene glycol which causes contact dermatitis in about 10% of people

  • Only consider an oral antibiotic if

    • medical condition which is associated with increased risk of severe infection (such as diabetes mellitus, or compromised immunity).

    • systemic signs of infection, such as fever.

    • severe infection, or at high risk for severe infection

      • for example if furunculosis or cellulitis spreads beyond the ear canal to the pinna, neck, or face.

    • If an oral antibiotic is required, consider are a 7-day course of flucloxacillin, or clarithromycin (if the person is allergic to penicillin)​

 

  • If fungal infection is suspected (signs of fungal growth in the ear canal):

    • Prescribe a topical antifungal preparation

      • ​Clotrimazole 1% solution.

      • Acetic acid 2% spray (unlicensed use).

      • Clioquinol and a corticosteroid 

    • Seek specialist advice if there is inadequate response.

 

  • If the cause is Irritant, or allergic dermatitis

    • avoid contact with the irritant or allergen

    • prescribe a topical corticosteroid.

      • Seborrhoeic dermatitis — treat topically with an antifungal/corticosteroid combination

  • Drain pus

    • if pus is causing severe pain and swelling

      • rarely required.

      • usually requires referral

        • a small pustule near the entrance to the ear canal may be drained by incising it with a surgical needle

  • Manage any aggravating or precipitating factors

    • diabetes mellitus

    • dermatitis

    • ear trauma​

 

  • Consider the need for investigations

    • ear swab proves rarely useful, but may be necessary if symptoms are persistent or recurrent.

 

  • Provide appropriate self-care advice to aid recovery and reduce risk of recurrence

    • keep the ears clean and dry

    • avoid the use of cotton buds

  • Treat generalized skin conditions such as eczema

 

  • Seek specialist advice if

    • symptoms persist

    • contact sensitivity is suspected

    • ear canal is occluded.

 

  • Refer to secondary care if

    • extensive cellulitis

    • extreme pain or discomfort

    • considerable discharge or extensive swelling of the auditory canal

    • sufficient earwax or debris to obstruct the application of topical medication

 

  • Follow up  

    • is not usually necessary,

    • recommended for people with 

      • severe otitis externa

      • chronic otitis externa

      • diabetes mellitus

      • compromised immunity.

 

  • Management of localized otitis externa includes:

    • Advising people to apply local heat using a warm flannel — this may be sufficient, as folliculitis is usually mild and self-limiting.

    • 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.

 

  • Urgent admission should be arranged for people with suspected malignant otitis.

 

Self-care

  • Keep ears clean and dry

    • avoid use of cotton buds

    • use a hair dryer (at the lowest heat setting) to dry the ear canal after hair washing, bathing, or swimming

    • swimming

      • use ear plugs and or a tight fitting cap 

      • people with acute otitis externa should abstain from water sports for at least 7 to 10 days

      • consider using acidifying ear drops or spray (such as EarCalm®) shortly before swimming, after swimming, and at bedtime​

 
PHS logo.jpg

Summary tables: infections in primary care

Management and treatment of common infections:

guidance for consultation and adaptation

Access

 
NICE.jpg
SIGN.jpg
journals.png

AAFP 

Acute Otitis Externa

September 2014

View/Access

NICE CSK Guidelines

Otitis Externa

February 2018

View/Access

Clinical practice guideline: acute otitis externa

American Academy of Otolaryngology

2014

View/Access

Otitis Externa

BMJ Best Practice

February 2019

View/Access

 
Ireland notes.png

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

otitis externa meds.png
 

CPD Quiz and Certificate

This activity attracts 1,0 CPD point

Scroll down the box above to view its entire content

All users who successfully complete the quiz are e-mailed a copy of their personalised CPD certificate.