Otitis Externa Flashcards
Definition of otitis externa
Diffuse inflammation of the skin and subdermis of the external auditory canal, which may also involve the pinna or the tympanic membrane. Also known as ‘swimmers ear’ or ‘tropical ear’
WHat are the different classifications of otitis externa
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Acute Diffuse Otitis Externa: Inflammation of less than 6 weeks duration
Typically caused by bacterial infection with Pseudomonas aeruginosa or Staphylococcus Aureus -
Chronic Otitis Externa: Inflammation which has lasted longer than 3 months
Persistent inflammation may be caused by fungal infection- due to Aspergillus or Candida Albicans -
Malignant or Necrotising Otitis Externa: A potentially life threatening progressive infection of the external auditory canal which may spread to cause osteomyelitis
Commonly caused by P. Aeruginosa and requires urgent ENT referral
Pain, oedema, exudate, micro abscess, granulation tissue, pseudomonas culture
Prevalence and peak incidence of otitis externa
- Otitis externa was a common diagnosis in all age groups, and was more common in females than in males up to the age of 65 years
- Prevalence increases at the end of the summer, especially in those aged 5-19 years
- 21% prevalence of repeated episodes
- Lifetime prevalence is around 10% for acute otitis externa
Causes of AOE
- AOE can be caused by: skin conditions (eczma, psoriasis, seborrheic eczma can produce debris in the ear canal), AOM (due to purulent middle ear secretions entering the external canal if there is perforation), contact dermatitis (shampoo, detergents etc), trauma to the ear canal (use of cotton buds, hearing aids, ear plugs, cleaning), water exposure
- COE can be caused by: skin conditions, uncontrolled DM (more likely in older adults- leading to infection), contact dermatitis, fungal or bacterial infection
- Malignant OE can be caused by: uncontrolled DM, older age, radiotherapy to the ear, head or neck, previous ear surgery or irrigation
Complications of AOE
- Chronic otitis externa
- Regional spread of infection causing cellulitis, perichondritis, or chondritis of the pinna and surrounding skin, abscess formation
- Fibrosis and stenosis of the ear canal, and fibrosis of the tympanic membrane with potential conductive hearing loss (particularly if chronic otitis externa)
- Myringitis (inflammation of the tympanic membrane) and perforation
- Malignant OE
Presentation of AOE
Must present with at least ONE typical symptom (rapid onset within 48hrs):
* Itching of the ear canal, ear pain and tenderness with possible jaw pain ear discharge, hearing loss due to ear canal occlusion
At least TWO typical signs:
* Tenderness of the tragus and/or pinna, red and oedematous ear canal (may be debris and discharge), erythema of the tympanic membrane, cellulitis of the pinna and adjacent skin, conductive hearing loss (less common)
Presentation of COE
- Constant itching in the ear and rarely mild discomfort or pain
- Typical signs: Loss of ear wax in external canal, dry scaly skin in the ear canal (varies in thickness and degree of stenosis), fluffy cotton-like debris, hyphae, or dots of black debris if fungal infection, conductive hearing loss
Presentation of malignant OE
- Unremitting and disproportionate ear pain, headache or purulent discharge, vertigo, profound conductive hearing loss
- Signs: Systemically unwell with high fever, granulation tissue seen on the floor of the ear canal and at the bone cartilage junction, ipsilateral fascial nerve palsy
Investigations for AOE
- Detailed history and top to toe examination
- Otoscopy and general examination of ear (starting with unaffected side)
- Consider arranging an ear swab for bacterial and fungal microscopy, culture, and sensitivity
Differentials for AOE
AOM, foreign body in the ear, impacted ear wax, skin conditions, mastoiditis
**Ramsay Hunt Syndrome **(herpes zoster affecting the facial nerve> severe pain, facial paralysis, loss of taste on the anterior two-thirds of the tongue, decreased lacrimation on involved side)
Management of AOE (<6 weeks)
Advice on self-care measures:
* Avoid damage to external canal (ear buds should be avoided), keep the ears clean and dry (avoid swimming, keep shampoo/ soap out of ears, consider using hair dryer after shower
* Analgesia and local heat application using a warm flannel
* For children over 12, consider using over-the-counter acetic acid 2% ear drops or spray (morning, evening, after water exposure)
* Ibuprofen/ paracetamol can be used for pain management. If severe pain and >12 yo can use co-codamol
Additional measures:
* Consider cleaning the external auditory canal (‘aural toilet’) to enable topical treatment
* Consider prescribing antibacterial ear drops: ciprofloxacin and dexamethasone otic (0.3%/0.1%) 2x day for 7-14 days (trust guidelines)
* Oral flucloxacillin OR clarithromycin (penicillin allergy) is rarely indicated but can be given if: severe infection, spread beyond auditory canal, diabetes or immunocompromised
* Arrange follow up if symptoms not improving after 48-72 hours of initial treatment (or resolved after 2 weeks of treatment)
Management of COE (>3 months)
- Self-care measures
- Manage any underlying RFs (skin conditions etc.)
- Consider arranging an ear swab for bacterial and fungal microscopy, culture and sensitivity
- If fungal infection suspected: Give topical Clotrimazole 1% solution, Acetic acid 2% spray, Clioquinol and corticosteroid (e.g. Locorten-Vioform)
If the cause is evident:
* Allergic dermatitis: topical corticosteroid
* Seborrhoeic dermatitis: antifungal/corticosteroid combination
If no cause evident:
* 7-day topical preparation containing only corticosteroid and no antibiotic. Consider co-prescribing acetic acid spray.
If malignant otitis suspected, urgent admission required
