otitis externa

risk factor

local injury

water exposure » bacterial build up

hearing aid, ear plug, ear protection, headphones »decrease ventilation + cerumen clearance

tortuous, narrow or collapsing canals

bony growths like exostoses

Diabetes

immunosuppression

radiotherapy » compromises the skin integrity, blood supply to the ear and bone narrowing

Pathogen:

Predominantly bacterial, AOE is commonly caused by Pseudomonas or Staph.A.

Fungal causes (otomycosis), like Aspergillus and Candida, often manifest as co-pathogens, in immunocompromised patients, or after prolonged use of topical antibacterial drops

History:

Direct trauma to the EAC and water exposure are the most common causes of AOE.

aboriginal and torres strait islander population:

clinical vigilance is advised when assessing Indigenous patients with acute otalgia due to a higher likelihood of NOE

P.E:

erythema, edema and tenderness in pinna and tragus

periauricular cellulitis

postauricular lymphadenopathy

Otalgia can be elicited by tragal pumping and pinna retraction.

otoscopy » inflamed, erythematous, edematous and moist canal, often painful (needs prior painkiller beforehand).

otorrhea or debris can give diagnostic info of the pathogen:

1-aspergillus white hyphae with black spores.

2-candida off-white sebaceous-like debris)

DX:

AOE usually involves identifiable risk factors and three key features. include:

symptoms (otalgia, pruritus and aural fullness) and

signs (tenderness, edema and erythema) of EAC inflammation

with rapid onset within 48 hours.

Acute tragal tenderness is widely accepted as a pathognomonic sign.

Both bacterial and fungal AOE have overlapping features of otalgia, otorrhoea, pruritus and erythema. Thus, otoscopy, swabs and contextual cues from history are necessary to confirm fungal AOE

DDX:

AOM/CSOM

mastoiditis

furunculosis

perichondritis

neoplasm/ abnormal growth

contact dermatitis

atopic dermatitis

seborrheic dermatitis

psoriasis

ramsay hunt syn. (VZV)

TMJ disorder

management:

Treatment with topical antibiotics and ear cleaning typically lead to significant improvement within 72 hours.

antibiotic:

Topical antibacterial ear drops, either quinolone based or non-quinolone based, are the first-line treatment for AOE and are empirically commenced without the need for swab confirmation because a significant proportion of cases are bacterial in origin. Generally, 65–90% of patients experience clinical improvement within 7–10 days, regardless of the specific topical formulation used

if you are sure about the TM integrity » non-quinolone based agents (cheap)

1. Framycetin 0.5% + gramicidin 0.005% + dexamethasone 0.05% (Sofradex) / AOE / 3 drops into the affected ear / 3–4 times a day until a few days after symptoms have cleared

2. Neomycin 0.25% + gramicidin 0.025% + triamcinolone 0.1% (Kenacomb Otic, Otocomb Otic), suitable for AOE & otomycosis / 3 drops into the affected ear/ 2 or 3 times a day until a few days after symptoms have cleared

if TM is not intact/ you are not sure » quinolone based agents (not ototoxic)

1. Ciprofloxacin 0.3% (Ciloxan) / 5 drops into the affected ear/ BID until a few days after symptoms have cleared

2. Ciprofloxacin 0.2% + hydrocortisone 1%(Ciproxin HC) / 3 drops into the affected ear/ BID until a few days after symptoms have cleared

systematic antibiotic is used in cases extending beyond EAC (periauricular cellulitis) or in high-risk populations (DM, immunocompromised)

drug delivery:

Ear drops are administered with the affected ear facing up, completely filling the EAC, and this is ideally done by another person.3,4 The patient should maintain this position for five minutes for sufficient penetration, with tragal pumping

you can use pope wick to apply topical antibiotics. As improvement is expected within 72 hours, the wick should be removed at this point and the EAC should be reassessed.

analgesia:

Paracetamol and NSAID » Regular dosing is recommended over ‘as needed’

Opioids: reserved for severe pain or before procedures, are rarely used most patients improve within 72 hours

topical analgesics should be avoided.

The steroid contained in the combination topical antibiotic formulation helps alleviate pain by reducing local inflammation and should be taken into account when prescribing.

complications:

complex or untreated cases, especially among diabetics, immunocompromised might lead to severe complications like necrotising otitis externa

NOE is osteomyelitis of temporal bone and skull base (SBO) »

• cranial nerve palsy

• meningitis

• brain abscesses

Refractory cases

Patients without clinical improvement within 72 hours of treatment should be reassessed, to ensure patient compliance and that the EAC is adequately receiving topical treatment. Patients might require repeat microsuction or wick insertion, and an ear swab can be performed if a non-pseudomonal cause (eg other bacteria, fungal) is suspected. Patients with persistent or worsening otologic symptoms, or those developing cellulitic or neurological signs, should be investigated for the possibility of NOE.

Indication for referral

Referral to ENT:

• condition worsens despite appropriate treatment

• condition persists beyond two weeks.

• significant debris or otorrhoea impedes drug delivery and clearance is not feasible in general practice, microsuction might be necessary and warrants referral.

• severe EAC oedema precludes wick insertion,

• focal neurological signs (eg facial nerve palsy) suspicious of NOE should have imaging and an urgent consultation through the emergency department .

• systemic features indicating infection beyond the EAC (eg periauricular cellulitis) also warrant prompt evaluation and potential hospital admission

Red flag symptoms to look for…

• Focal neurology (eg cranial nerve palsies)

• Periauricular cellulitis/abscess

• Systemic symptoms

» should be referred

Prevention

• Ear plugs prevent water retention in the EAC during water-based activities, and petroleum jelly applied around the ear plugs can enhance the seal.

• A hair dryer on the lowest heat setting or applying acetic acid/ethanol ear drops can dry EAC.

• Individuals who use hearing aids or similar devices should take frequent breaks for ventilation and clean the earpieces regularly.

• Cerumenolytics prevent cerumen impaction, but instrumentation (cotton buds) be avoided.

• Effective management of predisposing conditions like diabetes mellitus is crucial