Otitis Externa

• Otitis externa


  Inflammation of the skin in the external ear canal
• Otitis externa


  • Can be localised or diffuse
  • Can spread to the external ear (pinna)
  • Can be acute (less than three weeks) or chronic (more than three weeks)
• Swimmers ear


  Otitis externa caused by exposure to water whilst swimming
• Predisposing factors for otitis externa


  • Trauma from the ear canal (e.g., from cotton buds or earplugs)
  • Removal of ear wax (cerumen) which has a protective effect against infection
• Causes of inflammation in otitis externa

  • Bacterial infection
  • Fungal infection (e.g., aspergillus or candida)
  • Eczema
  • Seborrhoeic dermatitis
  • Contact dermatitis
• Pseudomonas aeruginosa


  A gram-negative aerobic rod-shaped bacteria that is a common bacterial cause of otitis externa
• Staphylococcus aureus


  A common bacterial cause of otitis externa
• Pseudomonas aeruginosa can colonise the lungs in patients with cystic fibrosis, significantly increasing their morbidity and mortality
• Pseudomonas aeruginosa is naturally resistant to many antibiotics, making it very difficult to treat in children with cystic fibrosis
• Pseudomonas aeruginosa can be treated with

  Aminoglycosides (e.g., gentamicin) or quinolones (e.g., ciprofloxacin)
• Typical symptoms of otitis externa

  • Ear pain
  • Discharge
  • Itchiness
  • Conductive hearing loss (if the ear becomes blocked)
• Examination findings in otitis externa

  • Erythema and swelling in the ear canal
  • Tenderness of the ear canal
  • Pus or discharge in the ear canal
  • Lymphadenopathy (swollen lymph nodes) in the neck or around the ear
  • Tympanic membrane may be obstructed by wax or discharge, and may be red if the otitis externa extends to it
• Diagnosis

  • Made clinically with an examination of the ear canal (otoscopy)
  • An ear swab can be used to identify the causative organism but is not usually required
• Mild otitis externa

  Treated with acetic acid 2% (available over the counter as EarCalm)
• Moderate otitis externa

  Treated with a topical antibiotic and steroid, e.g. neomycin, dexamethasone and acetic acid (Otomize spray), neomycin and betamethasone, gentamicin and hydrocortisone, or ciprofloxacin and dexamethasone
• Aminoglycosides (e.g., gentamicin and neomycin) are potentially ototoxic, rarely causing hearing loss if they get past the tympanic membrane
• It is essential to exclude a perforated tympanic membrane before using topical aminoglycosides in the ear
• Severe or systemic otitis externa

  May need oral antibiotics (e.g., flucloxacillin or clarithromycin) or discussion with ENT for admission and IV antibiotics
• Ear wick

  Made of sponge or gauze, containing topical treatment for otitis externa (e.g., antibiotics and steroids), inserted into the ear canal and left for a period of time
• Fungal otitis externa

  Treated with clotrimazole ear drops
• Malignant otitis externa

  A severe and potentially life-threatening form of otitis externa where the infection spreads to the bones surrounding the ear canal and skull
• Risk factors for malignant otitis externa

  • Diabetes
  • Immunosuppressant medications (e.g., chemotherapy)
  • HIV
• Malignant otitis externa

  • Symptoms are generally more severe than otitis externa, with persistent headache, severe pain and fever
  • Granulation tissue at the junction between the bone and cartilage in the ear canal is a key finding
• Management of malignant otitis externa

  Admission to hospital under the ENT team, IV antibiotics, and imaging (e.g., CT or MRI head) to assess the extent of the infection
• Complications of malignant otitis externa

  • Facial nerve damage and palsy
  • Other cranial nerve involvement (e.g., glossopharyngeal, vagus or accessory nerves)
  • Meningitis
  • Intracranial thrombosis
  • Death