Otitis Externa


Overview Acute otitis externa (AOE) is a common ear condition seen in the primary health care setting. Also known as ‘swimmer’s ear’ or ‘tropical ear’, it is prevalent in hot humid climates.  AOE is an inflammatory condition of the ear canal skin. The causes are infective or non-infective.

Otitis externa: Inflammation of the outer ear canal, often due to bacterial or fungal/ yeast infection. Otitis externa may occur in isolation, or can be associated with AOM and perforation of the tympanic membrane.
Acute Otitis Media Acute inflammation of the middle ear characterised by otalgia, bulging tympanic membrane and erythema +/- perforation and otorrhoea
Otitis Media with effusion (Glue Ear): Also known as serous otitis media characterised by fluid in the middle with without symptoms or sign of acute inflammation of ear.
Remember AOE usually results from excessive exposure to heat and moisture and is usually very painful. Treatment involves cleaning, keeping area dry and topical antibiotics


Nerve Supply
Great auricular (C2, C3) Cranial surface of auricle and the lower part of the lateral surface of auricle
Auriculotemporal branch of the trigeminal nerve Upper part of the lateral surface and most of the meatal skin
Facial nerve Posterior–inferior portion of the external ear canal and adjacent tympanic membrane
Glossopharyngeal nerve tympanic branch Mucosal surface of tympanic membrane
Vagus – auricular branch ‘Arnold’s nerve’ Supplies small areas of skin on the cranial auricular surface, posterior wall and floor of the meatus and adjoining part of the tympanic membrane


Classification of otitis externa
Infective Bacterial Acute diffuse
Acute localised furunolosis
Fungal Otomycosis
Viral Herpes zoster oticus
Necrotising (Bacterial/fungal) Malignant
Non-infective Dermatitis Seborrhoeic

Risk Factors

  • Water exposure
  • Wax
  • Dermatological
  • Trauma
  • Anatomical
  • Localised ear disease
  • Systemic disease - Diabetes, immunocompromised
  • Radiotherapy
  • Assistive hearing devices

Signs and Symptoms

Clinical presentation

  • Otalgia/pain
  • Oedema
  • Erythema
  • Otorrhoea
  • Debris in the canal
  • Itchiness
  • Hearing loss


  1. Rapid onset <48 hours in the past 3 weeks
  2. Signs of ear canal infection
  3. Symptoms of ear canal infection

Differential Diagnosis

  • Acute otitis media
  • Chronic otitis externa
  • Chronic suppurative otitis media
  • Contact dermatitis
  • Eczema
  • Furunculosis
  • Ramsay hunt syndrome
Ramsay hunt Syndrome Herpetic ulcers in canal; may have facial numbness/paralysis, severe pain, loss of taste (caused by herpes zoster - shingles)



Pneumatic otoscopy


AOE is an inflammatory condition of the ear canal skin. The causes are infective or non-infective.


  • Viral otitis externa
  • Fungal otitis external (otomycosis)
  • Acute locatlised otitis externa (furnculosis)
  • Acute diffuse otitis externa

Non - Infective

  • Seborrhoeic dermatitis
  • Atopic dermatitis



  • Paracetamol
  • NSAIDs
  • Opioid
  • Swab for micobiology, culture and sensitivity
  • Ear toilet
  • Topical antibiotics + steroids


  • Earplugs while swimming
  • Hair dryers on the lowest settings
  • Head tilting to remove water from the ear canal
  • Avoidance of self-cleaning or scratching the ear canal.

Complications and Prognosis


  • Mastoid osteomyelitis (nectrotising otits externa)
  • Cranial nerve palsy - facial nerve


  • Most patients will experience considerable improvement in symptoms after one day of treatment.
  • If there is no improvement within 48 to 72 hours, physicians should reevaluate for treatment adherence, misdiagnosis