Examination: Malignant (Necrotising) Otitis Externa

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Definition

  • It is a potentially life-threatening progressive infection of the external ear canal causing osteomyelitis of the temporal bone and adjacent structures.
  • Suspect a diagnosis of Malignant otitis externa if a person present with:

Typical Symptoms

  • Unremitting disproportionate ear pain,
  • headache,
  • purulent otorrhea,
  • fever or malaise
  • Vertigo
  • Profound conductive Hearing loss

Typical Signs:

  • Systemically unwell, high fever
  • Granulation tissue seen on the floor of the ear canal and at the bone cartilage junction;
  • exposed bone in the ear canal
  • Ipsilateral facial nerve palsy

Risk Factors:

  • Typically in old age,
  • Diabetes
  • immunocompromised patients

D/D:

  • Acute Otitis Externa
  • Chronic Otitis Externa
  • Otitis Media
  • Temporal bone osteomyelitis
  • Cholesteatoma
  • Skull base osteomyelitis:

Rx:

  • immediate referral to ENT specialist
  • They will do further examination
  • ay perform CT scan or MRI to assess the extent of the infection
  • After confirmation, antibiotics through veins and pain killer
  • In some cases, surgery to remove the infected tissue.
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Presenting Complaint

Ear Pain SOCRATES

  • Which ear - One side or both ears
  • Which part of the ear is painful: Front, back or inside - When did it start
  • Describe pain. Does the pain go anywhere Do you feel like it’s getting worse over time
  • Does anything make it worse, does anything make it better
  • On a scale of 0 - 10, 0 being no pain and 10 being the worst pain you’ve ever had, how would you score your pain

Hearing Loss ODIPARA

  • Which ear - One side or both ears
  • Do you feel like it’s getting worse over time
  • Does anything make it worse/ better

DDX

  • Otitis media and otitis externa
  • Ear wax
  • Trauma
  • Tumours of ear
  • Brain tumour
  • Meniere’s disease
  • Medications: aspirin, ibuprofen, antibiotics (gentamicin), water tablets (furosemide), cytotoxic meds
  • Occupation

MAFTOSA - ICE - PSYCHOSOCIAL

Examination

  • Obs
  • Examination of ear: tragus test +ve

Diagnosis

  • This is quite a serious infection and inflammation of the outer ear
  • It can happen often if you have other medical conditions and in immunocompromised people

Management

  • ASE
  • CT temporal bones or MRI
  • Antibiotics
  • Sometimes surgery from debridement
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NICE CKS

Otitis externa: Summary

  • Otitis externa describes diffuse inflammation of the skin and subdermis of the external ear canal, which may also involve the pinna or tympanic membrane.

    • Acute otitis externa is inflammation of less than 6 weeks duration, typically caused by bacterial infection with Pseudomonas aeruginosa or Staphylococcus aureus.
    • Chronic otitis externa is inflammation which has lasted longer than 3 months, and may be caused by fungal infection with Aspergillus species or Candida albicans.
    • Malignant otitis externa is a potentially life-threatening progressive infection of the external ear canal causing osteomyelitis of the temporal bone and adjacent structures.

  • Acute otitis externa may be associated with underlying skin conditions including contact dermatitis; acute otitis media; trauma to the ear canal; foreign body or obstruction in the ear canal; and water exposure.

  • Chronic otitis externa may also be associated with diabetes mellitus or other causes of immunocompromise; or fungal infection due to prolonged topical antibiotic or corticosteroid use.

  • Malignant otitis externa may be associated with diabetes mellitus or other causes of immunocompromise; older age; radiotherapy to the ear, head, or neck; and previous ear surgery or irrigation.

  • A diagnosis of otitis externa should be suspected if there is:

    • Acute — itch, pain, or discharge of the ear canal; hearing loss; tenderness of the tragus and/or pinna; red and oedematous ear canal; tympanic membrane erythema.
    • Chronic — itch in the ear, dry scaly skin or red moist skin in the ear canal, possible signs of fungal infection.
    • Malignant — unremitting pain, purulent ear discharge, systemic illness, hearing loss, granulation tissue in the ear canal, possible facial nerve palsy.

  • Assessment of suspected otitis externa includes:

    • Asking about the onset, nature, and severity of symptoms; impact on daily functioning; risk factors; previous episodes and treatments; previous ear surgery; associated comorbidities.
    • Examining the ear canal, pinna, and local lymph nodes for possible signs.
    • Arranging an ear swab for bacterial and fungal microscopy, culture, and sensitivity if there is treatment failure; severe, recurrent, or chronic infection; ear canal occlusion, or cellulitis beyond the ear canal.

  • Management of otitis externa includes:

    • Providing advice on sources of information and support.
    • Providing advice on self-care measures such as avoiding ear trauma; keeping the ear clean and dry; considering the use of over-the-counter acetic acid 2% ear drops or spray.
    • Managing any underlying causes or risk factors.
    • Advising on analgesia options.
    • Considering the need for ‘aural toilet’ if there is ear canal debris or exudate.
    • Considering prescribing a topical antibiotic or antifungal preparation, with or without corticosteroid, depending on clinical judgement.
    • Arranging follow up if there are persistent or severe symptoms; the person is immunocompromised; or there is ear canal stenosis or obstruction which is causing difficulty using topical treatment effectively.
    • Seeking specialist advice or arranging specialist referral, depending on clinical judgement.

CKS is only available in the UK | NICE

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