Step 1 of 7
Presentation & Symptom Pattern
Otalgia ± pruritus ± fullness ± otorrhoea ± hearing loss ± canal/auricular swelling — recognise the syndrome
Otitis externa presents as a constellation of ear pain, itching, a sense of fullness or blockage, otorrhoea, conductive hearing loss, and — in more advanced disease — swelling of the canal or auricle. The dominant symptom hints at the type: pain that is severe and worsened by chewing, by pressure on the tragus, or by pulling the pinna points to an acute diffuse bacterial infection of the canal skin, whereas itch with relatively little pain suggests a fungal or eczematous process. Otorrhoea is common and its character is informative — scanty and purulent in acute bacterial OE, fluffy and pruritic in otomycosis, profuse and offensive when there is an underlying middle-ear or cholesteatomatous source.
The unifying lesion is inflammation of the external auditory canal skin, and the cardinal sign that distinguishes OE from a middle-ear problem is tenderness on manipulation of the auricle — pain on tragal pressure or pinna traction — together with diffuse canal oedema and debris on otoscopy. The purpose of this first step is simply to recognise the syndrome and begin the orderly process that follows: triage for danger, characterise with history and examination, grade the severity, assign the type, and treat. The presentation is rarely diagnostic of the cause on its own — which is why the algorithm, not the first impression, drives management.
- Otalgia, pruritus, aural fullness, otorrhoea, conductive hearing loss, canal/auricular swelling — the OE syndrome
- Pain dominant (worse on tragal pressure / pinna traction / chewing) → bacterial; itch dominant → fungal or eczematous
- Cardinal sign separating OE from middle ear — tenderness on auricle manipulation + diffuse canal oedema
- Recognise the syndrome, then triage → characterise → grade → type → treat
★ High-yield pearls (chapter-wide)
- Otitis externa is a clinical diagnosis — diffuse canal oedema and tenderness on tragal pressure or pinna traction, usually with a recent history of water exposure or canal trauma, and the first job is not to treat but to decide whether this is routine OE or the necrotising disease that mimics it.
- Topical therapy is the mainstay and out-performs oral antibiotics for uncomplicated OE — aural toilet to clear the debris, an anti-pseudomonal or acidifying drop delivered to the medial canal, and dry-ear precautions resolve most cases; oral antibiotics are reserved for spread beyond the canal or the immunocompromised host.
- If the canal is too oedematous for the drops to reach the medial canal, place a wick — without it the most appropriate drop never reaches the infection and the patient returns no better.
- Pain out of all proportion to the otoscopic findings, severe nocturnal otalgia, or granulation tissue at the bony–cartilaginous junction in a diabetic or immunocompromised patient is necrotising otitis externa until proven otherwise — image, culture, biopsy, and start systemic anti-pseudomonal therapy.
- Granulation tissue in the canal must be biopsied — it is the hallmark of necrotising OE, but it is also how external-canal squamous cell carcinoma presents, and the two are indistinguishable without histology.
- Otomycosis is itch with minimal pain, fluffy or 'wet-newspaper' debris and visible hyphae, often after a course of antibiotic drops — meticulous debridement matters as much as the topical antifungal, and dry-ear discipline prevents the relentless recurrence.
- With a tympanic-membrane perforation or an open mastoid cavity, use a non-ototoxic fluoroquinolone drop (ofloxacin, ciprofloxacin) — aminoglycoside-containing drops (neomycin, gentamicin) can reach the inner ear and cause sensorineural hearing loss.
- Chronic, itchy OE that loses its cerumen and never quite settles is usually an underlying dermatosis — eczema, psoriasis, seborrhoeic or contact dermatitis — and it is treated by controlling the skin disease and the trigger, not by yet another antibiotic drop.
- In necrotising OE the canal can look almost normal while the skull base is being destroyed — do not stop treatment because the ear looks better; continue until symptoms resolve and the inflammatory markers (ESR, CRP) and gallium scan normalise, which can take weeks to months.
- Prevention is durable and simple — keep the canal dry, stop cotton-bud and instrument use, treat the underlying dermatosis, and in the recurrent swimmer or hearing-aid user a prophylactic acidifying drop restores the canal's protective acid mantle.
Evidence base
3 sources- HIGH
Wiegand S, Berner R, Schneider A · Dtsch Arztebl Int · 2019ReviewPMID 31064650
Contemporary review of otitis externa covering the symptom pattern, the bacterial and fungal aetiologies, risk factors (water, trauma, occlusion, diabetes), and the topical-led treatment of acute diffuse disease.
- MOD
Jackson EA & Geer K · Am Fam Physician · 2023Evidence reviewPMID 36791445
Rapid evidence review of acute otitis externa — diagnosis, the Pseudomonas/Staphylococcus microbiology, severity-based management, topical therapy, and the indications for systemic antibiotics and referral.
- HIGH
Rosenfeld RM, Schwartz SR, Cannon CR · Otolaryngol Head Neck Surg · 2014Practice guidelinePMID 24491310
The AAO-HNS evidence-based clinical practice guideline for acute otitis externa — diagnosis by rapid-onset canal inflammation, distinguishing it from other causes of otalgia and otorrhoea, assessing pain severity, and treating with topical preparations rather than systemic antibiotics for uncomplicated disease.
Decision tree
The triage screen is the first gate. Classification routes the stable patient to one of the aetiology-keyed pathways below. Cross-cut cards capture the chapter's must-not-miss rules.