Differential Diagnosis for Pus Coming Out of Ear

• Single Most Likely Diagnosis
  • Otitis Externa: This is the most common cause of pus coming out of the ear, especially if it's accompanied by itching, redness, and swelling of the outer ear. The condition is often caused by a bacterial infection, typically Staphylococcus aureus or Pseudomonas aeruginosa, and can be triggered by trauma to the ear canal, excessive moisture, or the use of earbuds/headphones.
• Other Likely Diagnoses
  • Otitis Media with Perforation: When the eardrum is perforated due to a middle ear infection (otitis media), pus can drain out through the ear canal. This condition often presents with ear pain, fever, and hearing loss.
  • Mastoiditis: An infection of the mastoid bone, located behind the ear, can cause pus to drain from the ear if the infection spreads to the ear canal. Symptoms include fever, ear pain, and swelling behind the ear.
  • Eczema or Psoriasis of the Ear Canal: These skin conditions can cause an inflammatory response leading to a discharge that might be mistaken for pus. They are typically accompanied by itching and visible skin changes.
• Do Not Miss Diagnoses
  • Malignant Otitis Externa: A severe infection of the external ear and skull base, more common in diabetic or immunocompromised patients. It can lead to significant complications, including cranial nerve paralysis and death if not promptly treated.
  • Petrous Apicitis: A rare but serious infection of the petrous part of the temporal bone, which can lead to severe complications, including meningitis, brain abscess, and death.
• Rare Diagnoses
  • Cholesteatoma: An abnormal skin growth in the middle ear behind the eardrum, which can cause destruction of the surrounding bone and tissue. It may lead to a chronic discharge that can be mistaken for pus.
  • Relapsing Polychondritis: A rare autoimmune disorder that can cause inflammation and destruction of cartilaginous structures, including those in the ear, potentially leading to a purulent discharge.
  • Necrotizing Otitis Externa with Intracranial Complications: Although more commonly associated with malignant otitis externa, any severe infection of the ear can potentially spread to intracranial structures, leading to serious complications.