[Durgical](https://durgical.com/en/) › [DurgiPedia](https://durgical.com/en/durgipedia/) › [Conditions](https://durgical.com/en/conditions/) › Necrotising (malignant) otitis externa

# Necrotising (malignant) otitis externa

A severe [ear canal](https://durgical.com/en/anatomy/external-acoustic-meatus/) infection that spreads into the skull base bone, mainly in older people with diabetes. Not cancer, but it can kill without long treatment.

Updated Nov 5, 2026

On this page

- The basics What it is
- Who gets it
- Causes
- Risk factors
- Classification
- Why it happens
- In ENT

- Clinical Symptoms and signs
- Red flags
- Diagnosis
- Differential diagnosis
- Complications
- Prognosis

- Treatment Treatment

- Study Test yourself

- Connections Connections

## What it is

An aggressive infection of the external ear canal that spreads to the temporal bone and skull base as osteomyelitis. «Malignant» refers to its course, not to cancer; it can involve cranial nerves, the venous sinuses and the brain.

See it in 3D

- [Ear canal](https://durgical.com/en/anatomy/external-acoustic-meatus/)
- [Temporal bones](https://durgical.com/en/anatomy/temporal-bone/)
- [Auricle](https://durgical.com/en/anatomy/auricle/)
- [Facial nerve (VII)](https://durgical.com/en/anatomy/facial-nerve/)

## +5

- [Stylomastoid foramen](https://durgical.com/en/anatomy/stylomastoid-foramen/)
- [Jugular foramen](https://durgical.com/en/anatomy/jugular-foramen/)
- [Glossopharyngeal nerve (IX)](https://durgical.com/en/anatomy/glossopharyngeal-nerve/)
- [Vagus nerve](https://durgical.com/en/anatomy/vagus-nerve/)
- [Sigmoid sinus](https://durgical.com/en/anatomy/sigmoid-sinus/)

## Who gets it

Rare. It occurs mostly in older adults with diabetes mellitus, and in people with HIV, chemotherapy or other immunosuppression. With the growing number of people with diabetes in Colombia, it should be suspected in any diabetic patient with a severe ear infection that does not improve.

## Causes

- Pseudomonas aeruginosa in most cases
- Less often Staphylococcus aureus (including MRSA) and other gram-negative bacteria
- Fungi (Aspergillus, Candida), especially in immunosuppressed people
- Spread from the canal floor through natural clefts in the cartilage to the skull base

## Risk factors

- Diabetes mellitus, especially poorly controlled
- Older age
- Immunosuppression: HIV, chemotherapy, transplant, corticosteroids
- Ear canal trauma, such as irrigation or instrumentation
- Radiotherapy to the [head and neck](https://durgical.com/en/anatomy/region/head-and-neck/)

## Classification

- Limited to the ear canal and adjacent soft tissue
- Skull base osteomyelitis
- With cranial nerve palsy (facial nerve first, then glossopharyngeal, vagus, accessory and hypoglossal)
- With intracranial spread: venous sinus thrombosis, meningitis, abscess

## Symptoms and signs

- Severe, persistent ear pain, often worse at night and out of proportion to the findings
- Purulent ear discharge
- Granulation tissue on the floor of the canal at the bony-cartilaginous junction
- Headache and pain at the [temporomandibular joint](https://durgical.com/en/anatomy/temporomandibular-joint/)
- Hearing loss and fullness
- Fever is often absent

## Red flags

- Facial palsy or other cranial nerve palsy (hoarseness, dysphagia)
- Otitis externa that does not improve with topical treatment in a diabetic or immunosuppressed person
- Granulation tissue in the canal of an older diabetic patient
- Severe headache, altered consciousness, neck stiffness
- Weight loss or a mass (rule out carcinoma)

## Diagnosis

**Clinical**
Suspected from severe otalgia and granulation tissue in the canal floor in a diabetic or immunosuppressed person. Examination includes the cranial nerves, especially the [facial nerve](https://durgical.com/en/anatomy/facial-nerve/).

**Tests**
Raised ESR and CRP (useful to follow response); blood glucose and HbA1c; culture of the discharge or deep tissue before antibiotics when possible; biopsy of granulation tissue to exclude squamous cell carcinoma.

**Imaging**
CT of the [temporal bone](https://durgical.com/en/anatomy/temporal-bone/) shows bone erosion; MRI shows soft tissue and intracranial spread. Technetium bone scan is sensitive early; gallium or labelled white cell scans help follow activity.

## Differential diagnosis

- Severe acute otitis externa
- Squamous cell carcinoma of the ear canal
- Cholesteatoma of the external canal
- Mastoiditis
- Granulomatous diseases (tuberculosis, granulomatosis with polyangiitis)

## Treatment

**Acute**
Hospital admission, strict glycaemic control and referral to otolaryngology and infectious diseases; samples for culture are taken before antibiotics when possible.

**Medical**
Prolonged systemic antipseudomonal antibiotics (a fluoroquinolone such as ciprofloxacin, or an antipseudomonal beta-lactam), guided by culture, for at least six weeks; antifungals for fungal disease.

**Medical**
Regular aural toilet and topical antibiotic drops as an adjunct.

**Surgical**
Surgical debridement of necrotic bone or abscess drainage in selected cases; biopsy to exclude malignancy.

**Procedure**
Hyperbaric oxygen therapy is sometimes used as an adjunct in refractory disease.

**Follow-up**
Follow-up with symptoms, ESR or CRP and functional imaging to decide when to stop antibiotics; relapse can occur months later.

## Complications

- Facial palsy and lower cranial nerve palsies
- Sigmoid or lateral sinus thrombosis
- Meningitis and brain abscess
- Hearing loss
- Death, especially with multiple cranial neuropathies or intracranial spread

## Prognosis

With early diagnosis and prolonged antibiotics, most patients are cured, and mortality has fallen a great deal. Cranial nerve palsies, intracranial spread and fungal infection worsen the outlook; relapse is possible.

## Test yourself

Think of the answer, then tap the question to see it.

## Which organism causes most cases of necrotising otitis externa?

Pseudomonas aeruginosa.

## What is the typical patient?

An older adult with diabetes mellitus, or an immunosuppressed person, with severe otalgia and granulation tissue in the ear canal.

## Which cranial nerve is affected first, most often?

The facial nerve (VII), at the stylomastoid foramen.

## Why is a biopsy of the granulation tissue taken?

To exclude squamous cell carcinoma of the ear canal, which can look similar.

## Which laboratory markers are used to follow treatment response?

ESR and CRP.

[Add to my cards (5)](https://durgical.app/estudiar/?add=/en/conditions/necrotising-otitis-externa/)

## Why it happens

- [The ear: otitis media, cholesteatoma, otosclerosis and ear tumours](https://durgical.com/en/general-pathology/the-ear-otitis-media-cholesteatoma-otosclerosis-and-ear-tumours/)

## In ENT

- [External ear problems: wax, otomycosis, furuncle, perichondritis, exostoses and keratosis obturans](https://durgical.com/en/ent/external-ear-problems-wax-otomycosis-furuncle-perichondritis-exostoses-and-kerat/)
- [Imaging in ENT: which study for which question](https://durgical.com/en/ent/imaging-in-ent-which-study-for-which-question/)

## Connections

## Related conditions 7

- [Otitis externa](https://durgical.com/en/conditions/otitis-externa/)
- [Type 2 diabetes mellitus](https://durgical.com/en/conditions/type-2-diabetes-mellitus/)
- [Osteomyelitis](https://durgical.com/en/conditions/osteomyelitis/)
- [Acute mastoiditis](https://durgical.com/en/conditions/acute-mastoiditis/)
- [Bell palsy](https://durgical.com/en/conditions/bell-palsy/)
- [Head and neck squamous cell carcinoma (oral cavity and oropharynx, HPV)](https://durgical.com/en/conditions/head-and-neck-squamous-cell-carcinoma/)
- [HIV infection and AIDS](https://durgical.com/en/conditions/hiv-infection-and-aids/)

Educational information, not medical advice. For any symptom, see a health professional.

Sources: [Necrotizing (Malignant) Otitis Externa](https://www.ncbi.nlm.nih.gov/books/NBK556138/) (StatPearls (NCBI Bookshelf), 2023).

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Representative model, for educational purposes only.

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Source: https://durgical.com/en/conditions/necrotising-otitis-externa/
License: CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). Cite as: DurgiPedia (durgical.com), https://durgical.com/en/conditions/necrotising-otitis-externa/