Ear pain is a bread-and-butter ED presentation, but the spectrum of disease it represents ranges from a self-limiting viral acute otitis media in a toddler to life-threatening malignant (necrotising) otitis externa with skull base involvement in an immunocompromised adult. For trainees preparing MRCEM SBA practice questions, otitis sits squarely in the syllabus because it tests diagnostic reasoning, antimicrobial stewardship, recognition of complications, and safe-disposition decision-making simultaneously. The RCEM curriculum explicitly maps ear, nose and throat emergencies to the competencies examined in the MRCEM Single Best Answer, and questions in this domain are characterised by deceptively similar stems that require precise clinical discrimination.
MRCEM SBA practice questions: Key Points
- Malignant otitis externa is a rare but potentially fatal complication of otitis externa, almost exclusively in diabetic or immunocompromised patients, caused predominantly by Pseudomonas aeruginosa, and requires urgent specialist referral and systemic antipseudomonal therapy.
- Acute otitis media (AOM) management in the ED is governed by NICE guidance: most children do not require immediate antibiotics, and a delayed prescription strategy is appropriate for the majority of uncomplicated cases in children over 2 years.
- Mastoiditis must be excluded in any child with AOM and post-auricular swelling, erythema, tenderness or auricular displacement. CT of the temporal bones is the investigation of choice if clinically suspected.
- Otitis externa (OE) is managed with topical aural toilet and topical antibiotic-steroid drops; systemic antibiotics are not indicated unless there is spreading cellulitis or systemic features.
- The key examination discriminator between AOM and OE is the presence or absence of tragal tenderness and pain on pinna traction: both are hallmarks of OE, not AOM.
- Otitis media with effusion (OME) is not an acute infective condition and requires no antibiotic treatment; it should be referred to outpatient audiology or ENT rather than managed in the ED.
Definitions, Epidemiology and Why This Matters in the ED
Otitis in the ED encompasses three principal conditions: otitis externa, acute otitis media, and otitis media with effusion. Each has a distinct pathophysiology, patient demographic and management pathway, and conflating them is a reliable source of mark loss in MRCEM SBA exam questions.
Acute otitis media is predominantly a paediatric condition. Approximately 80% of children experience at least one episode before the age of 10, with peak incidence between 6 and 24 months of age. Risk factors include nursery attendance, passive tobacco smoke exposure, bottle-feeding, and craniofacial anomalies such as cleft palate or Down syndrome. In the ED, AOM most commonly presents either as a primary consultation or following failure of outpatient management. It represents one of the most common indications for antibiotic prescribing in UK primary care, making antimicrobial stewardship a central examination theme.
Otitis externa has a lifetime incidence of approximately 10% in the general population and a marked peak in adults aged 45 to 75 years. It is more prevalent during summer months and in those with frequent water exposure, earning its colloquial name of swimmer’s ear. Predisposing factors include trauma from cotton bud use, hearing aid wear, and underlying dermatological conditions such as eczema and psoriasis. Critically for the exam, diabetes mellitus and immunosuppression are the principal risk factors for malignant otitis externa, a condition with significant morbidity and mortality that the emergency physician must not miss.
The causative organisms differ meaningfully across conditions and are a frequent target of MRCEM SBA practice questions. In AOM, Streptococcus pneumoniae, Haemophilus influenzae and Moraxella catarrhalis are the dominant bacterial pathogens, but viral aetiology (respiratory syncytial virus, rhinovirus) accounts for up to 40% of cases. In uncomplicated OE, Pseudomonas aeruginosa and Staphylococcus aureus predominate, with fungal pathogens (particularly Aspergillus and Candida) emerging in chronic or post-antibiotic cases. Malignant OE is caused by Pseudomonas aeruginosa in the vast majority, with Aspergillus a rare but recognised cause in profoundly immunocompromised patients. Mastoiditis shares organisms with AOM but also includes Streptococcus pyogenes, S. aureus (including MRSA) and P. aeruginosa. This organism-condition mapping is consistently examined. The NICE Clinical Knowledge Summaries provide an accessible and exam-relevant overview of these causative organisms and their management.
Pathophysiology: The Science Behind the Stem
Understanding the underlying mechanisms helps candidates select the single best answer with confidence, rather than relying on pattern recognition alone.
AOM begins with viral upper respiratory tract infection. Eustachian tube dysfunction follows, generating negative middle ear pressure. This allows nasopharyngeal bacteria to colonise the middle ear cleft. The resulting inflammatory exudate within the closed middle ear space causes the cardinal features of AOM: otalgia, conductive hearing loss, and a bulging, erythematous, opaque tympanic membrane. Spontaneous rupture of the tympanic membrane produces otorrhoea and frequently provides symptomatic relief, which is why a child who abruptly stops crying after developing a purulent ear discharge has likely perforated. Importantly, a perforated AOM is not a contraindication to analgesia, and the perforation itself usually heals without intervention.
Mastoiditis represents direct extension of middle ear infection into the mastoid air cells. The periosteum overlying the mastoid becomes inflamed and, in the more serious subperiosteal abscess, pus collects beneath it. This produces the characteristic clinical picture of post-auricular erythema, swelling, tenderness and forward or downward displacement of the auricle. Untreated, intracranial extension can produce sigmoid sinus thrombosis, meningitis, or brain abscess, all of which are genuine emergencies.
Otitis externa results from disruption of the protective cerumen layer and skin of the external auditory canal. Moisture, trauma or dermatological disease permits bacterial or fungal colonisation. Canal oedema progressively narrows the lumen, causing pain that is disproportionate to visible external signs. In malignant OE, immune dysfunction (most commonly diabetic microangiopathy and neuropathy combined with impaired neutrophil function) allows Pseudomonas aeruginosa to invade perichondrium, cartilage and ultimately bone. Extension to the skull base can involve cranial nerves VII, IX, X and XI, making cranial nerve palsy a red flag that demands emergency imaging and inpatient management.
ED Assessment and Management
History and Examination
A structured history should clarify the onset, character and severity of otalgia, any associated otorrhoea, hearing change, fever, and preceding upper respiratory tract infection. Crucially, the examining clinician must document: tragal tenderness (OE), pain on pinna traction (OE), tympanic membrane appearances (AOM: bulging, erythematous, opaque; OME: dull, retracted, amber), post-auricular findings (mastoiditis), cranial nerve examination (malignant OE), and glycaemic status (malignant OE risk).
Pitfall for exam candidates: ear pain with a normal tympanic membrane requires a broad differential, including temporomandibular joint dysfunction, dental pathology, parotid disease and cervical spine pathology, all of which cause referred otalgia via shared sensory innervation. MRCEM SBA clinical scenarios frequently exploit this.
Investigations
Uncomplicated AOM and OE require no investigations in the ED. When mastoiditis is suspected clinically, CT of the temporal bones is the investigation of choice and should not be delayed in the presence of systemic sepsis or neurological features. Where malignant OE is suspected, blood glucose, inflammatory markers (CRP, ESR), and CT or MRI of the skull base are required; MRI is superior for assessing soft tissue and dural involvement. Urgent ENT involvement is mandatory.
Management: NICE Guidance and Antimicrobial Stewardship
For AOM, current NICE guidance recommends a no-antibiotic or delayed antibiotic approach for most children over 2 years with non-severe AOM. Immediate antibiotics are indicated for: children under 2 years with bilateral AOM, any child with otorrhoea, children who are systemically unwell, or those with high-risk comorbidities. First-line antibiotic is amoxicillin for 5 to 7 days. Co-amoxiclav is reserved for treatment failure or when a resistant organism is suspected. Adequate analgesia with paracetamol or ibuprofen is essential and often the single most effective intervention in the ED.
For otitis externa, topical treatment is first-line. Gentle aural toilet to clear debris is performed before instilling topical antibiotic-steroid drops. Acetic acid 2% spray is an alternative, particularly where perforation cannot be excluded. Systemic antibiotics are not routinely indicated; they are reserved for spreading cellulitis beyond the canal, systemic sepsis, or when canal oedema prevents effective topical therapy and an aural wick is used. Cotton bud use must be actively discouraged and the ear kept dry. The British National Formulary provides current formulary recommendations for topical aural preparations.
For malignant OE, emergency ENT referral and admission are mandatory. Systemic antipseudomonal antibiotics (typically ciprofloxacin orally or intravenous antipseudomonal therapy for severe cases) are commenced after microbiological sampling. Diabetic patients require glucose optimisation. Surgical debridement may be necessary. The BMJ and associated resources provide detailed reviews of the clinical approach to necrotising OE for those seeking a deeper understanding of this condition.
For mastoiditis, any suspected case warrants emergency ENT referral. Intravenous broad-spectrum antibiotics covering the organisms above are commenced after blood cultures. Surgical intervention (cortical mastoidectomy) or drainage of a subperiosteal abscess may be required.
How the MRCEM SBA Exam Tests This Topic
The MRCEM Single Best Answer examination tests otitis through clinical scenario stems that require the candidate to differentiate between conditions, select appropriate management, or identify the correct complication. Common question archetypes include:
- A diabetic adult with severe otalgia disproportionate to canal appearances, with granulation tissue visible at the bony-cartilaginous junction, asking for the single most appropriate next management step. The answer is urgent ENT referral and CT skull base, not topical drops alone.
- A 14-month-old with bilateral AOM and high fever: the question asks whether to prescribe immediate antibiotics. The answer is yes, because age under 2 years with bilateral disease is an indication for immediate antibiotic therapy per NICE.
- A 6-year-old with AOM and new post-auricular swelling with auricular displacement: the question asks for the most important next investigation. CT temporal bones is the correct answer, not tympanometry or audiometry.
- Differentiating OE from AOM: the question provides a stem with tragal tenderness, pain on manipulation of the pinna, and an intact drum. The single best answer is otitis externa, and first-line treatment is topical acetic acid or antibiotic-steroid drops, not oral antibiotics.
The RCEM curriculum maps these scenarios to the ENT and Head and Neck domain. Candidates who perform best in MRCEM SBA exam questions on this topic are those who have a systematic approach to the tympanic membrane and peri-auricular examination and who know the NICE decision thresholds precisely. The Royal College of Emergency Medicine publishes curriculum documentation that identifies the clinical presentations and levels of competence expected, and review of this alongside structured SBA revision is strongly recommended.
Revision Pearls: High-Yield Facts for the MRCEM SBA
- Tragal tenderness and pain on pinna traction are the clinical hallmarks of OE, not AOM. Memorise this discriminator.
- A bulging, opaque, erythematous tympanic membrane with loss of the light reflex is the definitive otoscopic finding in AOM. A dull, amber, retracted drum with a visible fluid level indicates OME, which does not require antibiotics.
- Immediate antibiotics in AOM are indicated for: age under 2 with bilateral disease, any otorrhoea, systemic illness, or high-risk comorbidities. All others can be managed with a delayed prescription or no prescription plus analgesia.
- Malignant OE affects immunocompromised and diabetic patients almost exclusively. Pseudomonas aeruginosa is the causative organism in the vast majority of cases. Granulation tissue at the floor of the external canal at the bony-cartilaginous junction is the pathognomonic finding.
- Cranial nerve VII palsy in the context of OE is a neurosurgical and ENT emergency. Do not discharge. CT or MRI skull base, inpatient admission, and urgent ENT review are mandatory.
- First-line antibiotic for AOM in children without penicillin allergy is amoxicillin for 5 to 7 days. Co-amoxiclav is second-line for treatment failure.
- Mastoiditis: post-auricular swelling with auricular displacement in a child with AOM is mastoiditis until proven otherwise. CT temporal bones is the investigation of choice, and intravenous antibiotics plus urgent ENT referral are the ED management priorities.
- Fungal OE (otomycosis) should be suspected when OE fails to respond to standard bacterial topical therapy, especially in patients who have received prolonged antibiotic drops. The canal classically shows a white or black fluffy material. Treatment is with topical antifungals such as clotrimazole.
Common Pitfalls: Where Candidates Lose Marks
- Prescribing systemic antibiotics for uncomplicated OE when topical therapy is the correct and evidence-based first-line approach.
- Failing to identify malignant OE in a diabetic patient presenting with disproportionately severe otalgia, interpreting the presentation as simple OE and discharging with drops.
- Confusing OME with AOM and prescribing antibiotics when none are indicated. OME is not an acute infective condition.
- Missing mastoiditis because post-auricular examination is omitted in a child with AOM.
- Selecting co-amoxiclav as first-line for AOM rather than amoxicillin, or prescribing a prolonged course beyond current NICE guidance duration.
- Attributing otalgia to ear pathology without considering referred pain from the temporomandibular joint, teeth or pharynx when the tympanic membrane and canal are normal.
- Not documenting cranial nerve examination in any patient with OE who is diabetic or immunocompromised, thereby missing early malignant OE.
How EM Learning Centre Supports Your MRCEM Single Best Answer Revision
Preparing for the MRCEM SBA exam requires more than reading guidelines in isolation. You need to apply clinical knowledge under exam conditions, identify your weak areas and consolidate understanding through structured feedback. The MRCEM Single Best Answer revision course at EM Learning Centre is designed by practising UK EM clinicians and maps directly to the RCEM curriculum. It includes worked MRCEM SBA practice questions across all the major clinical domains, including ENT emergencies such as otitis, with detailed answer rationales that go beyond the correct answer to explain why the distractors are wrong. This is the level of analytical preparation that separates candidates who pass from those who narrowly miss.
Whether you are beginning your revision or fine-tuning your approach in the final weeks before your exam, the EM Learning Centre homepage provides access to question banks, structured lesson content, and clinical scenario-based learning that reflects the precise style and difficulty of MRCEM SBA exam questions. Evidence-grounded, written at registrar level, and built around the conditions you will actually see and be tested on.
References
- National Institute for Health and Care Excellence. Otitis media (acute): antimicrobial prescribing. NICE guideline NG91. Available at: NICE (nice.org.uk)
- NICE Clinical Knowledge Summaries. Otitis externa. Available at: NICE Clinical Knowledge Summaries
- NICE Clinical Knowledge Summaries. Otitis media with effusion. Available at: NICE Clinical Knowledge Summaries
- Royal College of Emergency Medicine. RCEM Curriculum. Available at: Royal College of Emergency Medicine (rcem.ac.uk)
- British National Formulary. Ear preparations. Available at: British National Formulary (bnf.nice.org.uk)
- BMJ Best Practice and related clinical reviews on necrotising otitis externa. Available at: The BMJ (bmj.com)
