Differential Diagnosis

Common Diagnoses

Occasional Diagnoses

Rare Diagnoses

Ready Reckoner

Key distinguishing features of the most common diagnoses

OMOE Boils TraumaThroat Problems
Pain on Pulling Pinna and Pressing TragusNoYesYesPossibleNo
Red, Bulging EardrumYesNoNoNoNo
Pain on SwallowingNoNoNoNoYes

Possible Investigations


Possible:Ear swab.

Small Print:X-rays of TMJ, teeth and mastoid bone, FBC, Paul–Bunnell test.

  • Swab of ear canal useful if discharge present, after failure of empirical first-line treatment.
  • X-ray of mastoid bone excludes mastoiditis if mastoid clear – usually arranged by specialist. X-rays of TMJ and teeth are the remit of the dentist or oral surgeon.
  • FBC and Paul–Bunnell test useful if glandular fever suspected. The diagnosis provides a label and guides further advice, though no specific treatment exists.
  • Further specialist investigations may include CT/MRI as the only way adequately (noninvasively) to investigate the inner ear and temporal bone anatomy

Top Tips

  • Persistent debris in the ear canal will prevent resolution of OE and mask possible underlying causes. Aural toilet is essential.
  • If inserting the aural speculum causes pain, the diagnosis is likely to be otitis externa or a furuncle.
  • Don’t forget to ask about trauma – especially the use of a cotton bud. Excavating earwax with a bud tends to produce an inflamed canal and drum, mimicking infection.
  • Earache can be excruciating: Don’t underestimate the need for adequate analgesia while you establish and treat the cause.

Red Flags

  • Consider mastoiditis if foul-smelling discharge is present for more than 10 days. Look for swelling behind the ear and downward displacement of the pinna.
  • Consider necrotising (or malignant) otitis externa in elderly diabetics or the immunocompromised with otalgia apparently out of proportion to their otitis externa. They may have a high fever and a facial palsy too. Refer urgently.
  • Don’t be too ready to diagnose otitis media in children – URTIs and crying inevitably result in some redness of the drum. Indiscriminate prescribing may lead to iatrogenic problems or the masking of the true diagnosis.
  • Beware the elderly patient with intractable, unexplained earache – refer to exclude a nasopharyngeal carcinoma.
Report errors, or incorrect content by clicking here.